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href="#Use_in_unit_systems"> <div class="vector-toc-text"> 1.1 Use in unit systems </div> </a> <ul id="toc-Use_in_unit_systems-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Fundamental_role_in_physics" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Fundamental_role_in_physics"> <div class="vector-toc-text"> 2 Fundamental role in physics </div> </a> <button aria-controls="toc-Fundamental_role_in_physics-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Fundamental role in physics subsection </button> <ul id="toc-Fundamental_role_in_physics-sublist" class="vector-toc-list"> <li id="toc-Upper_limit_on_speeds" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Upper_limit_on_speeds"> <div class="vector-toc-text"> 2.1 Upper limit on speeds </div> </a> <ul id="toc-Upper_limit_on_speeds-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Faster-than-light_observations_and_experiments" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Faster-than-light_observations_and_experiments"> <div class="vector-toc-text"> 3 Faster-than-light observations and experiments </div> </a> <ul id="toc-Faster-than-light_observations_and_experiments-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Propagation_of_light" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Propagation_of_light"> <div class="vector-toc-text"> 4 Propagation of light </div> </a> <button aria-controls="toc-Propagation_of_light-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Propagation of light subsection </button> <ul id="toc-Propagation_of_light-sublist" class="vector-toc-list"> <li id="toc-In_a_medium" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#In_a_medium"> <div class="vector-toc-text"> 4.1 In a medium </div> </a> <ul id="toc-In_a_medium-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Practical_effects_of_finiteness" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Practical_effects_of_finiteness"> <div class="vector-toc-text"> 5 Practical effects of finiteness </div> </a> <button aria-controls="toc-Practical_effects_of_finiteness-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Practical effects of finiteness subsection </button> <ul id="toc-Practical_effects_of_finiteness-sublist" class="vector-toc-list"> <li id="toc-Small_scales" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Small_scales"> <div class="vector-toc-text"> 5.1 Small scales </div> </a> <ul id="toc-Small_scales-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Large_distances_on_Earth" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Large_distances_on_Earth"> <div class="vector-toc-text"> 5.2 Large distances on Earth </div> </a> <ul id="toc-Large_distances_on_Earth-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Spaceflight_and_astronomy" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Spaceflight_and_astronomy"> <div class="vector-toc-text"> 5.3 Spaceflight and astronomy </div> </a> <ul id="toc-Spaceflight_and_astronomy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Distance_measurement" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Distance_measurement"> <div class="vector-toc-text"> 5.4 Distance measurement </div> </a> <ul id="toc-Distance_measurement-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Measurement" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Measurement"> <div class="vector-toc-text"> 6 Measurement </div> </a> <button aria-controls="toc-Measurement-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Measurement subsection </button> <ul id="toc-Measurement-sublist" class="vector-toc-list"> <li id="toc-Astronomical_measurements" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Astronomical_measurements"> <div class="vector-toc-text"> 6.1 Astronomical measurements </div> </a> <ul id="toc-Astronomical_measurements-sublist" class="vector-toc-list"> <li id="toc-Astronomical_unit" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Astronomical_unit"> <div class="vector-toc-text"> 6.1.1 Astronomical unit </div> </a> <ul id="toc-Astronomical_unit-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Time_of_flight_techniques" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Time_of_flight_techniques"> <div class="vector-toc-text"> 6.2 Time of flight techniques </div> </a> <ul id="toc-Time_of_flight_techniques-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Electromagnetic_constants" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Electromagnetic_constants"> <div class="vector-toc-text"> 6.3 Electromagnetic constants </div> </a> <ul id="toc-Electromagnetic_constants-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Cavity_resonance" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Cavity_resonance"> <div class="vector-toc-text"> 6.4 Cavity resonance </div> </a> <ul id="toc-Cavity_resonance-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Interferometry" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Interferometry"> <div class="vector-toc-text"> 6.5 Interferometry </div> </a> <ul id="toc-Interferometry-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> 7 History </div> </a> <button aria-controls="toc-History-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle History subsection </button> <ul id="toc-History-sublist" class="vector-toc-list"> <li id="toc-Early_history" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Early_history"> <div class="vector-toc-text"> 7.1 Early history </div> </a> <ul id="toc-Early_history-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-First_measurement_attempts" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#First_measurement_attempts"> <div class="vector-toc-text"> 7.2 First measurement attempts </div> </a> <ul id="toc-First_measurement_attempts-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Connections_with_electromagnetism" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Connections_with_electromagnetism"> <div class="vector-toc-text"> 7.3 Connections with electromagnetism </div> </a> <ul id="toc-Connections_with_electromagnetism-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-"Luminiferous_aether"" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#"Luminiferous_aether""> <div class="vector-toc-text"> 7.4 "Luminiferous aether" </div> </a> <ul id="toc-"Luminiferous_aether"-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Special_relativity" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Special_relativity"> <div class="vector-toc-text"> 7.5 Special relativity </div> </a> <ul id="toc-Special_relativity-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Increased_accuracy_of_c_and_redefinition_of_the_metre_and_second" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Increased_accuracy_of_c_and_redefinition_of_the_metre_and_second"> <div class="vector-toc-text"> 7.6 Increased accuracy of c and redefinition of the metre and second </div> </a> <ul id="toc-Increased_accuracy_of_c_and_redefinition_of_the_metre_and_second-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Defined_as_an_explicit_constant" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Defined_as_an_explicit_constant"> <div class="vector-toc-text"> 7.7 Defined as an explicit constant </div> </a> <ul id="toc-Defined_as_an_explicit_constant-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> 8 See also </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> 9 Notes </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> 10 References </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> 11 Further reading </div> </a> <button aria-controls="toc-Further_reading-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Further reading subsection </button> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> <li id="toc-Historical_references" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Historical_references"> <div class="vector-toc-text"> 11.1 Historical references </div> </a> <ul id="toc-Historical_references-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Modern_references" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Modern_references"> <div class="vector-toc-text"> 11.2 Modern references </div> </a> <ul id="toc-Modern_references-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> 12 External links </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Toggle the table of contents </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">Speed of light</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 131 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-131" aria-hidden="true" > 131 languages </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Ligsnelheid" title="Ligsnelheid – Afrikaans" lang="af" hreflang="af" data-title="Ligsnelheid" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target">Afrikaans</a></li><li class="interlanguage-link interwiki-als mw-list-item"><a href="https://als.wikipedia.org/wiki/Lichtgeschwindigkeit" title="Lichtgeschwindigkeit – Alemannic" lang="gsw" hreflang="gsw" data-title="Lichtgeschwindigkeit" data-language-autonym="Alemannisch" data-language-local-name="Alemannic" class="interlanguage-link-target">Alemannisch</a></li><li class="interlanguage-link interwiki-am mw-list-item"><a href="https://am.wikipedia.org/wiki/%E1%8B%A8%E1%89%A5%E1%88%AD%E1%88%83%E1%8A%95_%E1%8D%8D%E1%8C%A5%E1%8A%90%E1%89%B5" title="የብርሃን ፍጥነት – Amharic" lang="am" hreflang="am" data-title="የብርሃን ፍጥነት" data-language-autonym="አማርኛ" data-language-local-name="Amharic" class="interlanguage-link-target">አማርኛ</a></li><li class="interlanguage-link interwiki-smn mw-list-item"><a href="https://smn.wikipedia.org/wiki/%C4%8Cuov%C3%A2li%C3%A4htu" title="Čuovâliähtu – Inari Sami" lang="smn" hreflang="smn" data-title="Čuovâliähtu" data-language-autonym="Anarâškielâ" data-language-local-name="Inari Sami" class="interlanguage-link-target">Anarâškielâ</a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B3%D8%B1%D8%B9%D8%A9_%D8%A7%D9%84%D8%B6%D9%88%D8%A1" title="سرعة الضوء – Arabic" lang="ar" hreflang="ar" data-title="سرعة الضوء" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target">العربية</a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Velocidat_d%27a_luz" title="Velocidat d'a luz – Aragonese" lang="an" hreflang="an" data-title="Velocidat d'a luz" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target">Aragonés</a></li><li class="interlanguage-link interwiki-as mw-list-item"><a href="https://as.wikipedia.org/wiki/%E0%A6%AA%E0%A7%8B%E0%A6%B9%E0%A7%B0%E0%A7%B0_%E0%A6%AC%E0%A7%87%E0%A6%97" title="পোহৰৰ বেগ – Assamese" lang="as" hreflang="as" data-title="পোহৰৰ বেগ" data-language-autonym="অসমীয়া" data-language-local-name="Assamese" class="interlanguage-link-target">অসমীয়া</a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Velocid%C3%A1_de_la_lluz" title="Velocidá de la lluz – Asturian" lang="ast" hreflang="ast" data-title="Velocidá de la lluz" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target">Asturianu</a></li><li class="interlanguage-link interwiki-gn mw-list-item"><a href="https://gn.wikipedia.org/wiki/Tesape_pya%27ekue" title="Tesape pya'ekue – Guarani" lang="gn" hreflang="gn" data-title="Tesape pya'ekue" data-language-autonym="Avañe'ẽ" data-language-local-name="Guarani" class="interlanguage-link-target">Avañe'ẽ</a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/%C4%B0%C5%9F%C4%B1q_s%C3%BCr%C9%99ti" title="İşıq sürəti – Azerbaijani" lang="az" hreflang="az" data-title="İşıq sürəti" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target">Azərbaycanca</a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%86%E0%A6%B2%E0%A7%8B%E0%A6%B0_%E0%A6%A6%E0%A7%8D%E0%A6%B0%E0%A7%81%E0%A6%A4%E0%A6%BF" title="আলোর দ্রুতি – Bangla" lang="bn" hreflang="bn" data-title="আলোর দ্রুতি" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target">বাংলা</a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/Kng-sok" title="Kng-sok – Minnan" lang="nan" hreflang="nan" data-title="Kng-sok" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="Minnan" class="interlanguage-link-target">閩南語 / Bân-lâm-gú</a></li><li class="interlanguage-link interwiki-ba mw-list-item"><a href="https://ba.wikipedia.org/wiki/%D0%AF%D2%A1%D1%82%D1%8B%D0%BB%D1%8B%D2%A1_%D1%82%D0%B8%D2%99%D0%BB%D0%B5%D0%B3%D0%B5" title="Яҡтылыҡ тиҙлеге – Bashkir" lang="ba" hreflang="ba" data-title="Яҡтылыҡ тиҙлеге" data-language-autonym="Башҡортса" data-language-local-name="Bashkir" class="interlanguage-link-target">Башҡортса</a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%A1%D0%BA%D0%BE%D1%80%D0%B0%D1%81%D1%86%D1%8C_%D1%81%D0%B2%D1%8F%D1%82%D0%BB%D0%B0" title="Скорасць святла – Belarusian" lang="be" hreflang="be" data-title="Скорасць святла" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target">Беларуская</a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%A5%D1%83%D1%82%D0%BA%D0%B0%D1%81%D1%8C%D1%86%D1%8C_%D1%81%D1%8C%D0%B2%D1%8F%D1%82%D0%BB%D0%B0" title="Хуткасьць сьвятла – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Хуткасьць сьвятла" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target">Беларуская (тарашкевіца)</a></li><li class="interlanguage-link interwiki-bh mw-list-item"><a href="https://bh.wikipedia.org/wiki/%E0%A4%85%E0%A4%81%E0%A4%9C%E0%A5%8B%E0%A4%B0%E0%A4%BF%E0%A4%AF%E0%A4%BE_%E0%A4%95%E0%A5%87_%E0%A4%97%E0%A4%A4%E0%A4%BF%E0%A4%B5%E0%A5%87%E0%A4%97" title="अँजोरिया के गतिवेग – Bhojpuri" lang="bh" hreflang="bh" data-title="अँजोरिया के गतिवेग" data-language-autonym="भोजपुरी" data-language-local-name="Bhojpuri" class="interlanguage-link-target">भोजपुरी</a></li><li class="interlanguage-link interwiki-bcl mw-list-item"><a href="https://bcl.wikipedia.org/wiki/Rikas_nin_liwanag" title="Rikas nin liwanag – Central Bikol" lang="bcl" hreflang="bcl" data-title="Rikas nin liwanag" data-language-autonym="Bikol Central" data-language-local-name="Central Bikol" class="interlanguage-link-target">Bikol Central</a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A1%D0%BA%D0%BE%D1%80%D0%BE%D1%81%D1%82_%D0%BD%D0%B0_%D1%81%D0%B2%D0%B5%D1%82%D0%BB%D0%B8%D0%BD%D0%B0%D1%82%D0%B0" title="Скорост на светлината – Bulgarian" lang="bg" hreflang="bg" data-title="Скорост на светлината" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target">Български</a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Brzina_svjetlosti" title="Brzina svjetlosti – Bosnian" lang="bs" hreflang="bs" data-title="Brzina svjetlosti" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target">Bosanski</a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Tizh_ar_goulo%C3%B9" title="Tizh ar gouloù – Breton" lang="br" hreflang="br" data-title="Tizh ar gouloù" data-language-autonym="Brezhoneg" data-language-local-name="Breton" class="interlanguage-link-target">Brezhoneg</a></li><li class="interlanguage-link interwiki-bxr mw-list-item"><a href="https://bxr.wikipedia.org/wiki/%D0%93%D1%8D%D1%80%D1%8D%D0%BB%D1%8D%D0%B9_%D1%85%D1%83%D1%80%D0%B4%D0%B0%D0%BD" title="Гэрэлэй хурдан – Russia Buriat" lang="bxr" hreflang="bxr" data-title="Гэрэлэй хурдан" data-language-autonym="Буряад" data-language-local-name="Russia Buriat" class="interlanguage-link-target">Буряад</a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Velocitat_de_la_llum" title="Velocitat de la llum – Catalan" lang="ca" hreflang="ca" data-title="Velocitat de la llum" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target">Català</a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%C3%87%D1%83%D1%82%C4%83_%D1%85%C4%83%D0%B2%C4%83%D1%80%D1%82%D0%BB%C4%83%D1%85%C4%95" title="Çутă хăвăртлăхĕ – Chuvash" lang="cv" hreflang="cv" data-title="Çутă хăвăртлăхĕ" data-language-autonym="Чӑвашла" data-language-local-name="Chuvash" class="interlanguage-link-target">Чӑвашла</a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Rychlost_sv%C4%9Btla" title="Rychlost světla – Czech" lang="cs" hreflang="cs" data-title="Rychlost světla" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target">Čeština</a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/Cyflymder_golau" title="Cyflymder golau – Welsh" lang="cy" hreflang="cy" data-title="Cyflymder golau" data-language-autonym="Cymraeg" data-language-local-name="Welsh" class="interlanguage-link-target">Cymraeg</a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Lysets_hastighed" title="Lysets hastighed – Danish" lang="da" hreflang="da" data-title="Lysets hastighed" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target">Dansk</a></li><li class="interlanguage-link interwiki-de badge-Q17437796 badge-featuredarticle mw-list-item" title="featured article badge"><a href="https://de.wikipedia.org/wiki/Lichtgeschwindigkeit" title="Lichtgeschwindigkeit – German" lang="de" hreflang="de" data-title="Lichtgeschwindigkeit" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target">Deutsch</a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Valguse_kiirus" title="Valguse kiirus – Estonian" lang="et" hreflang="et" data-title="Valguse kiirus" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target">Eesti</a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A4%CE%B1%CF%87%CF%8D%CF%84%CE%B7%CF%84%CE%B1_%CF%84%CE%BF%CF%85_%CF%86%CF%89%CF%84%CF%8C%CF%82" title="Ταχύτητα του φωτός – Greek" lang="el" hreflang="el" data-title="Ταχύτητα του φωτός" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target">Ελληνικά</a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Velocidad_de_la_luz" title="Velocidad de la luz – Spanish" lang="es" hreflang="es" data-title="Velocidad de la luz" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target">Español</a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Lumrapido" title="Lumrapido – Esperanto" lang="eo" hreflang="eo" data-title="Lumrapido" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target">Esperanto</a></li><li class="interlanguage-link interwiki-ext mw-list-item"><a href="https://ext.wikipedia.org/wiki/Veloci%C3%A1_de_la_lus" title="Velociá de la lus – Extremaduran" lang="ext" hreflang="ext" data-title="Velociá de la lus" data-language-autonym="Estremeñu" data-language-local-name="Extremaduran" class="interlanguage-link-target">Estremeñu</a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Argiaren_abiadura" title="Argiaren abiadura – Basque" lang="eu" hreflang="eu" data-title="Argiaren abiadura" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target">Euskara</a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B3%D8%B1%D8%B9%D8%AA_%D9%86%D9%88%D8%B1" title="سرعت نور – Persian" lang="fa" hreflang="fa" data-title="سرعت نور" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target">فارسی</a></li><li class="interlanguage-link interwiki-hif mw-list-item"><a href="https://hif.wikipedia.org/wiki/Parkaas_ke_raftaar" title="Parkaas ke raftaar – Fiji Hindi" lang="hif" hreflang="hif" data-title="Parkaas ke raftaar" data-language-autonym="Fiji Hindi" data-language-local-name="Fiji Hindi" class="interlanguage-link-target">Fiji Hindi</a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Vitesse_de_la_lumi%C3%A8re" title="Vitesse de la lumière – French" lang="fr" hreflang="fr" data-title="Vitesse de la lumière" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target">Français</a></li><li class="interlanguage-link interwiki-fy mw-list-item"><a href="https://fy.wikipedia.org/wiki/Ljochtfaasje" title="Ljochtfaasje – Western Frisian" lang="fy" hreflang="fy" data-title="Ljochtfaasje" data-language-autonym="Frysk" data-language-local-name="Western Frisian" class="interlanguage-link-target">Frysk</a></li><li class="interlanguage-link interwiki-fur mw-list-item"><a href="https://fur.wikipedia.org/wiki/Velocit%C3%A2t_de_l%C3%BBs" title="Velocitât de lûs – Friulian" lang="fur" hreflang="fur" data-title="Velocitât de lûs" data-language-autonym="Furlan" data-language-local-name="Friulian" class="interlanguage-link-target">Furlan</a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Luas_an_tsolais" title="Luas an tsolais – Irish" lang="ga" hreflang="ga" data-title="Luas an tsolais" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target">Gaeilge</a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Velocidade_da_luz" title="Velocidade da luz – Galician" lang="gl" hreflang="gl" data-title="Velocidade da luz" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target">Galego</a></li><li class="interlanguage-link interwiki-gu mw-list-item"><a href="https://gu.wikipedia.org/wiki/%E0%AA%AA%E0%AB%8D%E0%AA%B0%E0%AA%95%E0%AA%BE%E0%AA%B6%E0%AA%A8%E0%AB%8B_%E0%AA%B5%E0%AB%87%E0%AA%97" title="પ્રકાશનો વેગ – Gujarati" lang="gu" hreflang="gu" data-title="પ્રકાશનો વેગ" data-language-autonym="ગુજરાતી" data-language-local-name="Gujarati" class="interlanguage-link-target">ગુજરાતી</a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%B9%9B%EC%9D%98_%EC%86%8D%EB%A0%A5" title="빛의 속력 – Korean" lang="ko" hreflang="ko" data-title="빛의 속력" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target">한국어</a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D4%BC%D5%B8%D6%82%D5%B5%D5%BD%D5%AB_%D5%A1%D6%80%D5%A1%D5%A3%D5%B8%D6%82%D5%A9%D5%B5%D5%B8%D6%82%D5%B6" title="Լույսի արագություն – Armenian" lang="hy" hreflang="hy" data-title="Լույսի արագություն" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target">Հայերեն</a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%95%E0%A4%BE%E0%A4%B6_%E0%A4%95%E0%A4%BE_%E0%A4%B5%E0%A5%87%E0%A4%97" title="प्रकाश का वेग – Hindi" lang="hi" hreflang="hi" data-title="प्रकाश का वेग" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target">हिन्दी</a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Brzina_svjetlosti" title="Brzina svjetlosti – Croatian" lang="hr" hreflang="hr" data-title="Brzina svjetlosti" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target">Hrvatski</a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Laju_cahaya" title="Laju cahaya – Indonesian" lang="id" hreflang="id" data-title="Laju cahaya" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target">Bahasa Indonesia</a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Velocitate_de_lumine" title="Velocitate de lumine – Interlingua" lang="ia" hreflang="ia" data-title="Velocitate de lumine" data-language-autonym="Interlingua" data-language-local-name="Interlingua" class="interlanguage-link-target">Interlingua</a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Lj%C3%B3shra%C3%B0i" title="Ljóshraði – Icelandic" lang="is" hreflang="is" data-title="Ljóshraði" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target">Íslenska</a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Velocit%C3%A0_della_luce" title="Velocità della luce – Italian" lang="it" hreflang="it" data-title="Velocità della luce" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target">Italiano</a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%9E%D7%94%D7%99%D7%A8%D7%95%D7%AA_%D7%94%D7%90%D7%95%D7%A8" title="מהירות האור – Hebrew" lang="he" hreflang="he" data-title="מהירות האור" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target">עברית</a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%A1%E1%83%98%E1%83%9C%E1%83%90%E1%83%97%E1%83%9A%E1%83%98%E1%83%A1_%E1%83%A1%E1%83%98%E1%83%A9%E1%83%A5%E1%83%90%E1%83%A0%E1%83%94" title="სინათლის სიჩქარე – Georgian" lang="ka" hreflang="ka" data-title="სინათლის სიჩქარე" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target">ქართული</a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%96%D0%B0%D1%80%D1%8B%D2%9B_%D0%B6%D1%8B%D0%BB%D0%B4%D0%B0%D0%BC%D0%B4%D1%8B%D2%93%D1%8B" title="Жарық жылдамдығы – Kazakh" lang="kk" hreflang="kk" data-title="Жарық жылдамдығы" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target">Қазақша</a></li><li class="interlanguage-link interwiki-kw mw-list-item"><a href="https://kw.wikipedia.org/wiki/Tooth_golow" title="Tooth golow – Cornish" lang="kw" hreflang="kw" data-title="Tooth golow" data-language-autonym="Kernowek" data-language-local-name="Cornish" class="interlanguage-link-target">Kernowek</a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Kasi_ya_nuru" title="Kasi ya nuru – Swahili" lang="sw" hreflang="sw" data-title="Kasi ya nuru" data-language-autonym="Kiswahili" data-language-local-name="Swahili" class="interlanguage-link-target">Kiswahili</a></li><li class="interlanguage-link interwiki-ht mw-list-item"><a href="https://ht.wikipedia.org/wiki/Vit%C3%A8s_limy%C3%A8" title="Vitès limyè – Haitian Creole" lang="ht" hreflang="ht" data-title="Vitès limyè" data-language-autonym="Kreyòl ayisyen" data-language-local-name="Haitian Creole" class="interlanguage-link-target">Kreyòl ayisyen</a></li><li class="interlanguage-link interwiki-gcr mw-list-item"><a href="https://gcr.wikipedia.org/wiki/Vit%C3%A8s_di_limy%C3%A8" title="Vitès di limyè – Guianan Creole" lang="gcr" hreflang="gcr" data-title="Vitès di limyè" data-language-autonym="Kriyòl gwiyannen" data-language-local-name="Guianan Creole" class="interlanguage-link-target">Kriyòl gwiyannen</a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%96%D0%B0%D1%80%D1%8B%D0%BA_%D1%8B%D0%BB%D0%B4%D0%B0%D0%BC%D0%B4%D1%8B%D0%B3%D1%8B" title="Жарык ылдамдыгы – Kyrgyz" lang="ky" hreflang="ky" data-title="Жарык ылдамдыгы" data-language-autonym="Кыргызча" data-language-local-name="Kyrgyz" class="interlanguage-link-target">Кыргызча</a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Celeritas_lucis" title="Celeritas lucis – Latin" lang="la" hreflang="la" data-title="Celeritas lucis" data-language-autonym="Latina" data-language-local-name="Latin" class="interlanguage-link-target">Latina</a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Gaismas_%C4%81trums" title="Gaismas ātrums – Latvian" lang="lv" hreflang="lv" data-title="Gaismas ātrums" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target">Latviešu</a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/Liichtvitess" title="Liichtvitess – Luxembourgish" lang="lb" hreflang="lb" data-title="Liichtvitess" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target">Lëtzebuergesch</a></li><li class="interlanguage-link interwiki-lez mw-list-item"><a href="https://lez.wikipedia.org/wiki/%D0%AD%D0%BA%D1%83%D1%8C%D0%BD%D0%B8%D0%BD_%D0%B7%D0%B0%D1%80%D0%B1%D0%B2%D0%B0%D0%BB" title="Экуьнин зарбвал – Lezghian" lang="lez" hreflang="lez" data-title="Экуьнин зарбвал" data-language-autonym="Лезги" data-language-local-name="Lezghian" class="interlanguage-link-target">Лезги</a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/%C5%A0viesos_greitis" title="Šviesos greitis – Lithuanian" lang="lt" hreflang="lt" data-title="Šviesos greitis" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target">Lietuvių</a></li><li class="interlanguage-link interwiki-lfn mw-list-item"><a href="https://lfn.wikipedia.org/wiki/Rapidia_de_lus" title="Rapidia de lus – Lingua Franca Nova" lang="lfn" hreflang="lfn" data-title="Rapidia de lus" data-language-autonym="Lingua Franca Nova" data-language-local-name="Lingua Franca Nova" class="interlanguage-link-target">Lingua Franca Nova</a></li><li class="interlanguage-link interwiki-jbo mw-list-item"><a href="https://jbo.wikipedia.org/wiki/nilsutra_lo_gusni" title="nilsutra lo gusni – Lojban" lang="jbo" hreflang="jbo" data-title="nilsutra lo gusni" data-language-autonym="La .lojban." data-language-local-name="Lojban" class="interlanguage-link-target">La .lojban.</a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Velocit%C3%A0_de_la_lus" title="Velocità de la lus – Lombard" lang="lmo" hreflang="lmo" data-title="Velocità de la lus" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target">Lombard</a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/F%C3%A9nysebess%C3%A9g" title="Fénysebesség – Hungarian" lang="hu" hreflang="hu" data-title="Fénysebesség" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target">Magyar</a></li><li class="interlanguage-link interwiki-mk badge-Q17437798 badge-goodarticle mw-list-item" title="good article badge"><a href="https://mk.wikipedia.org/wiki/%D0%91%D1%80%D0%B7%D0%B8%D0%BD%D0%B0_%D0%BD%D0%B0_%D1%81%D0%B2%D0%B5%D1%82%D0%BB%D0%B8%D0%BD%D0%B0%D1%82%D0%B0" title="Брзина на светлината – Macedonian" lang="mk" hreflang="mk" data-title="Брзина на светлината" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target">Македонски</a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B4%95%E0%B4%BE%E0%B4%B6%E0%B4%B5%E0%B5%87%E0%B4%97%E0%B4%82" title="പ്രകാശവേഗം – Malayalam" lang="ml" hreflang="ml" data-title="പ്രകാശവേഗം" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target">മലയാളം</a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%95%E0%A4%BE%E0%A4%B6%E0%A4%BE%E0%A4%9A%E0%A4%BE_%E0%A4%B5%E0%A5%87%E0%A4%97" title="प्रकाशाचा वेग – Marathi" lang="mr" hreflang="mr" data-title="प्रकाशाचा वेग" data-language-autonym="मराठी" data-language-local-name="Marathi" class="interlanguage-link-target">मराठी</a></li><li class="interlanguage-link interwiki-arz mw-list-item"><a href="https://arz.wikipedia.org/wiki/%D8%B3%D8%B1%D8%B9%D8%A9_%D8%A7%D9%84%D9%86%D9%88%D8%B1" title="سرعة النور – Egyptian Arabic" lang="arz" hreflang="arz" data-title="سرعة النور" data-language-autonym="مصرى" data-language-local-name="Egyptian Arabic" class="interlanguage-link-target">مصرى</a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Kelajuan_cahaya" title="Kelajuan cahaya – Malay" lang="ms" hreflang="ms" data-title="Kelajuan cahaya" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target">Bahasa Melayu</a></li><li class="interlanguage-link interwiki-min mw-list-item"><a href="https://min.wikipedia.org/wiki/Laju_cahayo" title="Laju cahayo – Minangkabau" lang="min" hreflang="min" data-title="Laju cahayo" data-language-autonym="Minangkabau" data-language-local-name="Minangkabau" class="interlanguage-link-target">Minangkabau</a></li><li class="interlanguage-link interwiki-cdo mw-list-item"><a href="https://cdo.wikipedia.org/wiki/Gu%C5%8Fng-s%C3%B3k" title="Guŏng-sók – Mindong" lang="cdo" hreflang="cdo" data-title="Guŏng-sók" data-language-autonym="閩東語 / Mìng-dĕ̤ng-ngṳ̄" data-language-local-name="Mindong" class="interlanguage-link-target">閩東語 / Mìng-dĕ̤ng-ngṳ̄</a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%93%D1%8D%D1%80%D0%BB%D0%B8%D0%B9%D0%BD_%D1%85%D1%83%D1%80%D0%B4" title="Гэрлийн хурд – Mongolian" lang="mn" hreflang="mn" data-title="Гэрлийн хурд" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target">Монгол</a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%A1%E1%80%9C%E1%80%84%E1%80%BA%E1%80%B8%E1%80%A1%E1%80%9C%E1%80%BB%E1%80%84%E1%80%BA" title="အလင်းအလျင် – Burmese" lang="my" hreflang="my" data-title="အလင်းအလျင်" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target">မြန်မာဘာသာ</a></li><li class="interlanguage-link interwiki-fj mw-list-item"><a href="https://fj.wikipedia.org/wiki/Totolo_ni_rarama" title="Totolo ni rarama – Fijian" lang="fj" hreflang="fj" data-title="Totolo ni rarama" data-language-autonym="Na Vosa Vakaviti" data-language-local-name="Fijian" class="interlanguage-link-target">Na Vosa Vakaviti</a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Lichtsnelheid" title="Lichtsnelheid – Dutch" lang="nl" hreflang="nl" data-title="Lichtsnelheid" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target">Nederlands</a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E5%85%89%E9%80%9F" title="光速 – Japanese" lang="ja" hreflang="ja" data-title="光速" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target">日本語</a></li><li class="interlanguage-link interwiki-frr mw-list-item"><a href="https://frr.wikipedia.org/wiki/Faard_faan%27t_laacht" title="Faard faan't laacht – Northern Frisian" lang="frr" hreflang="frr" data-title="Faard faan't laacht" data-language-autonym="Nordfriisk" data-language-local-name="Northern Frisian" class="interlanguage-link-target">Nordfriisk</a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Lysets_hastighet" title="Lysets hastighet – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Lysets hastighet" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target">Norsk bokmål</a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Ljosfarten" title="Ljosfarten – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Ljosfarten" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target">Norsk nynorsk</a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Velocitat_de_la_lutz" title="Velocitat de la lutz – Occitan" lang="oc" hreflang="oc" data-title="Velocitat de la lutz" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target">Occitan</a></li><li class="interlanguage-link interwiki-om mw-list-item"><a href="https://om.wikipedia.org/wiki/Saffisa_ifaa" title="Saffisa ifaa – Oromo" lang="om" hreflang="om" data-title="Saffisa ifaa" data-language-autonym="Oromoo" data-language-local-name="Oromo" class="interlanguage-link-target">Oromoo</a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Yorug%CA%BBlik_tezligi" title="Yorugʻlik tezligi – Uzbek" lang="uz" hreflang="uz" data-title="Yorugʻlik tezligi" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target">Oʻzbekcha / ўзбекча</a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%B0%E0%A9%8C%E0%A8%B8%E0%A8%BC%E0%A8%A8%E0%A9%80_%E0%A8%A6%E0%A9%80_%E0%A8%97%E0%A8%A4%E0%A9%80" title="ਰੌਸ਼ਨੀ ਦੀ ਗਤੀ – Punjabi" lang="pa" hreflang="pa" data-title="ਰੌਸ਼ਨੀ ਦੀ ਗਤੀ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target">ਪੰਜਾਬੀ</a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D8%B1%D9%88%D8%B4%D9%86%DB%8C_%D8%AF%DB%8C_%D8%B1%D9%81%D8%AA%D8%A7%D8%B1" title="روشنی دی رفتار – Western Punjabi" lang="pnb" hreflang="pnb" data-title="روشنی دی رفتار" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target">پنجابی</a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%D8%AF_%D9%84%D9%85%D8%B1_%D8%B3%D8%B1%D8%B9%D8%AA" title="د لمر سرعت – Pashto" lang="ps" hreflang="ps" data-title="د لمر سرعت" data-language-autonym="پښتو" data-language-local-name="Pashto" class="interlanguage-link-target">پښتو</a></li><li class="interlanguage-link interwiki-jam mw-list-item"><a href="https://jam.wikipedia.org/wiki/Spiid_a_lait" title="Spiid a lait – Jamaican Creole English" lang="jam" hreflang="jam" data-title="Spiid a lait" data-language-autonym="Patois" data-language-local-name="Jamaican Creole English" class="interlanguage-link-target">Patois</a></li><li class="interlanguage-link interwiki-km mw-list-item"><a href="https://km.wikipedia.org/wiki/%E1%9E%9B%E1%9F%92%E1%9E%94%E1%9E%BF%E1%9E%93%E1%9E%96%E1%9E%93%E1%9F%92%E1%9E%9B%E1%9E%BA" title="ល្បឿនពន្លឺ – Khmer" lang="km" hreflang="km" data-title="ល្បឿនពន្លឺ" data-language-autonym="ភាសាខ្មែរ" data-language-local-name="Khmer" class="interlanguage-link-target">ភាសាខ្មែរ</a></li><li class="interlanguage-link interwiki-nds mw-list-item"><a href="https://nds.wikipedia.org/wiki/Lichtsnellheid" title="Lichtsnellheid – Low German" lang="nds" hreflang="nds" data-title="Lichtsnellheid" data-language-autonym="Plattdüütsch" data-language-local-name="Low German" class="interlanguage-link-target">Plattdüütsch</a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Pr%C4%99dko%C5%9B%C4%87_%C5%9Bwiat%C5%82a" title="Prędkość światła – Polish" lang="pl" hreflang="pl" data-title="Prędkość światła" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target">Polski</a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Velocidade_da_luz" title="Velocidade da luz – Portuguese" lang="pt" hreflang="pt" data-title="Velocidade da luz" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target">Português</a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Viteza_luminii" title="Viteza luminii – Romanian" lang="ro" hreflang="ro" data-title="Viteza luminii" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target">Română</a></li><li class="interlanguage-link interwiki-rue mw-list-item"><a href="https://rue.wikipedia.org/wiki/%D0%A8%D0%B2%D1%8B%D0%B4%D0%BA%D0%BE%D1%81%D1%82%D1%8C_%D1%81%D0%B2%D1%96%D1%82%D0%BB%D0%B0" title="Швыдкость світла – Rusyn" lang="rue" hreflang="rue" data-title="Швыдкость світла" data-language-autonym="Русиньскый" data-language-local-name="Rusyn" class="interlanguage-link-target">Русиньскый</a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A1%D0%BA%D0%BE%D1%80%D0%BE%D1%81%D1%82%D1%8C_%D1%81%D0%B2%D0%B5%D1%82%D0%B0" title="Скорость света – Russian" lang="ru" hreflang="ru" data-title="Скорость света" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target">Русский</a></li><li class="interlanguage-link interwiki-sco mw-list-item"><a href="https://sco.wikipedia.org/wiki/Speed_o_licht" title="Speed o licht – Scots" lang="sco" hreflang="sco" data-title="Speed o licht" data-language-autonym="Scots" data-language-local-name="Scots" class="interlanguage-link-target">Scots</a></li><li class="interlanguage-link interwiki-stq mw-list-item"><a href="https://stq.wikipedia.org/wiki/Luchtgauegaid" title="Luchtgauegaid – Saterland Frisian" lang="stq" hreflang="stq" data-title="Luchtgauegaid" data-language-autonym="Seeltersk" data-language-local-name="Saterland Frisian" class="interlanguage-link-target">Seeltersk</a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Shpejt%C3%ABsia_e_drit%C3%ABs" title="Shpejtësia e dritës – Albanian" lang="sq" hreflang="sq" data-title="Shpejtësia e dritës" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target">Shqip</a></li><li class="interlanguage-link interwiki-scn mw-list-item"><a href="https://scn.wikipedia.org/wiki/Vilucitati_d%C3%A2_luci" title="Vilucitati dâ luci – Sicilian" lang="scn" hreflang="scn" data-title="Vilucitati dâ luci" data-language-autonym="Sicilianu" data-language-local-name="Sicilian" class="interlanguage-link-target">Sicilianu</a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B6%86%E0%B6%BD%E0%B7%9D%E0%B6%9A%E0%B6%BA%E0%B7%9A_%E0%B7%80%E0%B7%9A%E0%B6%9C%E0%B6%BA" title="ආලෝකයේ වේගය – Sinhala" lang="si" hreflang="si" data-title="ආලෝකයේ වේගය" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target">සිංහල</a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Speed_of_light" title="Speed of light – Simple English" lang="en-simple" hreflang="en-simple" data-title="Speed of light" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target">Simple English</a></li><li class="interlanguage-link interwiki-sk badge-Q17437796 badge-featuredarticle mw-list-item" title="featured article badge"><a href="https://sk.wikipedia.org/wiki/R%C3%BDchlos%C5%A5_svetla_vo_v%C3%A1kuu" title="Rýchlosť svetla vo vákuu – Slovak" lang="sk" hreflang="sk" data-title="Rýchlosť svetla vo vákuu" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target">Slovenčina</a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Hitrost_svetlobe" title="Hitrost svetlobe – Slovenian" lang="sl" hreflang="sl" data-title="Hitrost svetlobe" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target">Slovenščina</a></li><li class="interlanguage-link interwiki-so mw-list-item"><a href="https://so.wikipedia.org/wiki/Xawaaraha_Ileyska" title="Xawaaraha Ileyska – Somali" lang="so" hreflang="so" data-title="Xawaaraha Ileyska" data-language-autonym="Soomaaliga" data-language-local-name="Somali" class="interlanguage-link-target">Soomaaliga</a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D8%AE%DB%8E%D8%B1%D8%A7%DB%8C%DB%8C%DB%8C_%DA%95%D9%88%D9%88%D9%86%D8%A7%DA%A9%DB%8C" title="خێراییی ڕووناکی – Central Kurdish" lang="ckb" hreflang="ckb" data-title="خێراییی ڕووناکی" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target">کوردی</a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%91%D1%80%D0%B7%D0%B8%D0%BD%D0%B0_%D1%81%D0%B2%D0%B5%D1%82%D0%BB%D0%BE%D1%81%D1%82%D0%B8" title="Брзина светлости – Serbian" lang="sr" hreflang="sr" data-title="Брзина светлости" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target">Српски / srpski</a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Brzina_svjetlosti" title="Brzina svjetlosti – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Brzina svjetlosti" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target">Srpskohrvatski / српскохрватски</a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/Laju_cahaya" title="Laju cahaya – Sundanese" lang="su" hreflang="su" data-title="Laju cahaya" data-language-autonym="Sunda" data-language-local-name="Sundanese" class="interlanguage-link-target">Sunda</a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Valonnopeus" title="Valonnopeus – Finnish" lang="fi" hreflang="fi" data-title="Valonnopeus" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target">Suomi</a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Ljusets_hastighet" title="Ljusets hastighet – Swedish" lang="sv" hreflang="sv" data-title="Ljusets hastighet" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target">Svenska</a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Bilis_ng_liwanag" title="Bilis ng liwanag – Tagalog" lang="tl" hreflang="tl" data-title="Bilis ng liwanag" data-language-autonym="Tagalog" data-language-local-name="Tagalog" class="interlanguage-link-target">Tagalog</a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%92%E0%AE%B3%E0%AE%BF%E0%AE%AF%E0%AE%BF%E0%AE%A9%E0%AF%8D_%E0%AE%B5%E0%AF%87%E0%AE%95%E0%AE%AE%E0%AF%8D" title="ஒளியின் வேகம் – Tamil" lang="ta" hreflang="ta" data-title="ஒளியின் வேகம்" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target">தமிழ்</a></li><li class="interlanguage-link interwiki-tt mw-list-item"><a href="https://tt.wikipedia.org/wiki/%D0%AF%D0%BA%D1%82%D1%8B%D0%BB%D1%8B%D0%BA_%D1%82%D0%B8%D0%B7%D0%BB%D0%B5%D0%B3%D0%B5" title="Яктылык тизлеге – Tatar" lang="tt" hreflang="tt" data-title="Яктылык тизлеге" data-language-autonym="Татарча / tatarça" data-language-local-name="Tatar" class="interlanguage-link-target">Татарча / tatarça</a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%95%E0%B0%BE%E0%B0%82%E0%B0%A4%E0%B0%BF_%E0%B0%B5%E0%B1%87%E0%B0%97%E0%B0%82" title="కాంతి వేగం – Telugu" lang="te" hreflang="te" data-title="కాంతి వేగం" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target">తెలుగు</a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%AD%E0%B8%B1%E0%B8%95%E0%B8%A3%E0%B8%B2%E0%B9%80%E0%B8%A3%E0%B9%87%E0%B8%A7%E0%B8%82%E0%B8%AD%E0%B8%87%E0%B9%81%E0%B8%AA%E0%B8%87" title="อัตราเร็วของแสง – Thai" lang="th" hreflang="th" data-title="อัตราเร็วของแสง" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target">ไทย</a></li><li class="interlanguage-link interwiki-tg mw-list-item"><a href="https://tg.wikipedia.org/wiki/%D0%A1%D1%83%D1%80%D1%8A%D0%B0%D1%82%D0%B8_%D1%80%D3%AF%D1%88%D0%BD%D0%BE%D3%A3" title="Суръати рӯшноӣ – Tajik" lang="tg" hreflang="tg" data-title="Суръати рӯшноӣ" data-language-autonym="Тоҷикӣ" data-language-local-name="Tajik" class="interlanguage-link-target">Тоҷикӣ</a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/I%C5%9F%C4%B1k_h%C4%B1z%C4%B1" title="Işık hızı – Turkish" lang="tr" hreflang="tr" data-title="Işık hızı" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target">Türkçe</a></li><li class="interlanguage-link interwiki-kcg mw-list-item"><a href="https://kcg.wikipedia.org/wiki/Cung_sai" title="Cung sai – Tyap" lang="kcg" hreflang="kcg" data-title="Cung sai" data-language-autonym="Tyap" data-language-local-name="Tyap" class="interlanguage-link-target">Tyap</a></li><li class="interlanguage-link interwiki-udm mw-list-item"><a href="https://udm.wikipedia.org/wiki/%D0%AE%D0%B3%D1%8B%D1%82%D0%BB%D1%8D%D0%BD_%D3%9D%D0%BE%D0%B3%D0%BB%D1%8B%D0%BA%D0%B5%D0%B7" title="Югытлэн ӝоглыкез – Udmurt" lang="udm" hreflang="udm" data-title="Югытлэн ӝоглыкез" data-language-autonym="Удмурт" data-language-local-name="Udmurt" class="interlanguage-link-target">Удмурт</a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A8%D0%B2%D0%B8%D0%B4%D0%BA%D1%96%D1%81%D1%82%D1%8C_%D1%81%D0%B2%D1%96%D1%82%D0%BB%D0%B0" title="Швидкість світла – Ukrainian" lang="uk" hreflang="uk" data-title="Швидкість світла" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target">Українська</a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D8%B1%D9%88%D8%B4%D9%86%DB%8C_%DA%A9%DB%8C_%D8%B1%D9%81%D8%AA%D8%A7%D8%B1" title="روشنی کی رفتار – Urdu" lang="ur" hreflang="ur" data-title="روشنی کی رفتار" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target">اردو</a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/Ve%C5%82osit%C3%A0_de_%C5%82a_%C5%82uze" title="Vełosità de ła łuze – Venetian" lang="vec" hreflang="vec" data-title="Vełosità de ła łuze" data-language-autonym="Vèneto" data-language-local-name="Venetian" class="interlanguage-link-target">Vèneto</a></li><li class="interlanguage-link interwiki-vep mw-list-item"><a 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For other uses, see <a href="/wiki/Speed_of_light_(disambiguation)" class="mw-disambig" title="Speed of light (disambiguation)">Speed of light (disambiguation)</a> and <a href="/wiki/Lightspeed_(disambiguation)" class="mw-disambig" title="Lightspeed (disambiguation)">Lightspeed (disambiguation)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox"><caption class="infobox-title">Speed of light</caption><tbody><tr><td colspan="2" class="infobox-image"><a href="/wiki/File:Earth_to_Sun_-_en.png" class="mw-file-description"><img alt="The distance from the Sun to Earth is shown as 150 million kilometres, an approximate average. Sizes to scale." src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Earth_to_Sun_-_en.png/330px-Earth_to_Sun_-_en.png" decoding="async" width="330" height="187" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Earth_to_Sun_-_en.png/495px-Earth_to_Sun_-_en.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Earth_to_Sun_-_en.png/660px-Earth_to_Sun_-_en.png 2x" data-file-width="841" data-file-height="476" /></a><div class="infobox-caption">On average, <a href="/wiki/Sunlight" title="Sunlight">sunlight</a> takes 8 minutes and 17 seconds to travel from the <a href="/wiki/Sun" title="Sun">Sun</a> to <a href="/wiki/Earth" title="Earth">Earth</a>.</div></td></tr><tr><th colspan="2" class="infobox-header">Exact value</th></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal"><a href="/wiki/Metre_per_second" title="Metre per second">metres per second</a></th><td class="infobox-data">299792458</td></tr><tr><th colspan="2" class="infobox-header">Approximate values (to three significant digits)</th></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal"><a href="/wiki/Kilometres_per_hour" title="Kilometres per hour">kilometres per hour</a></th><td class="infobox-data">1080000000</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal"><a href="/wiki/Miles_per_hour" title="Miles per hour">miles per second</a></th><td class="infobox-data">186000</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal"><a href="/wiki/Miles_per_hour" title="Miles per hour">miles per hour</a><a href="#cite_note-1">[1]</a></th><td class="infobox-data">671000000</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal"><a href="/wiki/Astronomical_unit" title="Astronomical unit">astronomical units</a> per day</th><td class="infobox-data">173<a href="#cite_note-2">[Note 1]</a></td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal"><a href="/wiki/Parsec" title="Parsec">parsecs</a> per year</th><td class="infobox-data">0.307<a href="#cite_note-3">[Note 2]</a></td></tr><tr><th colspan="2" class="infobox-header">Approximate light signal travel times</th></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">Distance</th><td class="infobox-data">Time</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">one <a href="/wiki/Foot_(unit)" title="Foot (unit)">foot</a></th><td class="infobox-data">1.0 <a href="/wiki/Nanosecond" title="Nanosecond">ns</a></td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">one <a href="/wiki/Metre" title="Metre">metre</a></th><td class="infobox-data">3.3 ns</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">from <a href="/wiki/Geostationary_orbit" title="Geostationary orbit">geostationary orbit</a> to Earth</th><td class="infobox-data">119 <a href="/wiki/Millisecond" title="Millisecond">ms</a></td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">the length of Earth's <a href="/wiki/Equator" title="Equator">equator</a></th><td class="infobox-data">134 ms</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">from <a href="/wiki/Moon" title="Moon">Moon</a> to Earth</th><td class="infobox-data">1.3 <a href="/wiki/Second" title="Second">s</a></td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">from <a href="/wiki/Sun" title="Sun">Sun</a> to Earth (1 <a href="/wiki/Astronomical_unit" title="Astronomical unit">AU</a>)</th><td class="infobox-data">8.3 <a href="/wiki/Minute" title="Minute">min</a></td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">one <a href="/wiki/Light-year" title="Light-year">light-year</a></th><td class="infobox-data">1.0 <a href="/wiki/Year" title="Year">year</a></td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">one parsec</th><td class="infobox-data">3.26 years</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">from the <a href="/wiki/Proxima_Centauri" title="Proxima Centauri">nearest star</a> to Sun (1.3 <abbr title="parsec">pc</abbr>)</th><td class="infobox-data">4.2 years</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">from the <a href="/wiki/Sagittarius_Dwarf_Spheroidal_Galaxy" title="Sagittarius Dwarf Spheroidal Galaxy">nearest galaxy</a> to Earth</th><td class="infobox-data">70000 years</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">across the <a href="/wiki/Milky_Way" title="Milky Way">Milky Way</a></th><td class="infobox-data">87400 years</td></tr><tr><th scope="row" class="infobox-label" style="font-weight:normal">from the <a href="/wiki/Andromeda_Galaxy" title="Andromeda Galaxy">Andromeda Galaxy</a> to Earth</th><td class="infobox-data">2.5 million 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.sidebar{width:100%!important;clear:both;float:none!important;margin-left:0!important;margin-right:0!important}}body.skin--responsive .mw-parser-output .sidebar a>img{max-width:none!important}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media print{body.ns-0 .mw-parser-output .sidebar{display:none!important}}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><table class="sidebar sidebar-collapse nomobile nowraplinks plainlist"><tbody><tr><th class="sidebar-title"><a href="/wiki/Special_relativity" title="Special relativity">Special relativity</a></th></tr><tr><td class="sidebar-image"><a href="/wiki/File:World_line.svg" class="mw-file-description" title="The world line: a diagrammatic representation of spacetime"><img alt="The world line: a diagrammatic representation of spacetime" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/16/World_line.svg/200px-World_line.svg.png" decoding="async" width="200" height="204" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/16/World_line.svg/300px-World_line.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/16/World_line.svg/400px-World_line.svg.png 2x" data-file-width="481" data-file-height="491" /></a></td></tr><tr><td class="sidebar-content" style="padding-bottom:0.6em;"> <ul><li><a href="/wiki/Principle_of_relativity" title="Principle of relativity">Principle of relativity</a></li> <li><a href="/wiki/Theory_of_relativity" title="Theory of relativity">Theory of relativity</a></li> <li><a href="/wiki/Formulations_of_special_relativity" title="Formulations of special relativity">Formulations</a></li></ul></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;;color: var(--color-base)"><div class="sidebar-list-title-c">Foundations</div></div><div class="sidebar-list-content mw-collapsible-content" style="padding-top:0;"> <ul><li><a href="/wiki/Postulates_of_special_relativity" title="Postulates of special relativity">Einstein's postulates</a></li> <li><a href="/wiki/Inertial_frame_of_reference" title="Inertial frame of reference">Inertial frame of reference</a></li> <li><a class="mw-selflink selflink">Speed of light</a></li> <li><a href="/wiki/Maxwell%27s_equations" title="Maxwell's equations">Maxwell's equations</a></li> <li><a href="/wiki/Lorentz_transformation" title="Lorentz transformation">Lorentz transformation</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;;color: var(--color-base)"><div class="sidebar-list-title-c">Consequences</div></div><div class="sidebar-list-content mw-collapsible-content" style="padding-top:0;"> <ul><li><a href="/wiki/Time_dilation" title="Time dilation">Time dilation</a></li> <li><a href="/wiki/Length_contraction" title="Length contraction">Length contraction</a></li> <li><a href="/wiki/Mass_in_special_relativity" title="Mass in special relativity">Relativistic mass</a></li> <li><a href="/wiki/Mass%E2%80%93energy_equivalence" title="Mass–energy equivalence">Mass–energy equivalence</a></li> <li><a href="/wiki/Relativity_of_simultaneity" title="Relativity of simultaneity">Relativity of simultaneity</a></li> <li><a href="/wiki/Relativistic_Doppler_effect" title="Relativistic Doppler effect">Relativistic Doppler effect</a></li> <li><a href="/wiki/Thomas_precession" title="Thomas precession">Thomas precession</a></li> <li><a href="/wiki/Relativistic_disk" title="Relativistic disk">Relativistic disk</a></li> <li><a href="/wiki/Bell%27s_spaceship_paradox" title="Bell's spaceship paradox">Bell's spaceship paradox</a></li> <li><a href="/wiki/Ehrenfest_paradox" title="Ehrenfest paradox">Ehrenfest paradox</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;;color: var(--color-base)"><div class="sidebar-list-title-c"><a href="/wiki/Spacetime" title="Spacetime">Spacetime</a></div></div><div class="sidebar-list-content mw-collapsible-content" style="padding-top:0;"> <ul><li><a href="/wiki/Minkowski_space" title="Minkowski space">Minkowski spacetime</a></li> <li><a href="/wiki/Minkowski_diagram" class="mw-redirect" title="Minkowski diagram">Spacetime diagram</a></li> <li><a href="/wiki/World_line" title="World line">World line</a></li> <li><a href="/wiki/Light_cone" title="Light cone">Light cone</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;;color: var(--color-base)"><div class="sidebar-list-title-c"><a href="/wiki/Dynamics_(mechanics)" class="mw-redirect" title="Dynamics (mechanics)">Dynamics</a></div></div><div class="sidebar-list-content mw-collapsible-content" style="padding-top:0;"> <ul><li><a href="/wiki/Proper_time" title="Proper time">Proper time</a></li> <li><a href="/wiki/Invariant_mass" title="Invariant mass">Proper mass</a></li> <li><a href="/wiki/Four-momentum" title="Four-momentum">Four-momentum</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;;color: var(--color-base)"><div class="sidebar-list-title-c"><div class="hlist" style="font-size:110%;"><ul><li><a href="/wiki/History_of_special_relativity" title="History of special relativity">History</a></li><li>Precursors</li></ul></div></div></div><div class="sidebar-list-content mw-collapsible-content" style="padding-top:0;"> <ul><li><a href="/wiki/Galilean_invariance" title="Galilean invariance">Galilean relativity</a></li> <li><a href="/wiki/Galilean_transformation" title="Galilean transformation">Galilean transformation</a></li> <li><a href="/wiki/Aether_theories" title="Aether theories">Aether theories</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;;color: var(--color-base)"><div class="sidebar-list-title-c">People</div></div><div class="sidebar-list-content mw-collapsible-content" style="padding-top:0;"><div class="hlist"> <ul><li><a href="/wiki/Albert_Einstein" title="Albert Einstein">Einstein</a></li> <li><a href="/wiki/Arnold_Sommerfeld" title="Arnold Sommerfeld">Sommerfeld</a></li> <li><a href="/wiki/Albert_A._Michelson" title="Albert A. Michelson">Michelson</a></li> <li><a href="/wiki/Edward_W._Morley" title="Edward W. Morley">Morley</a></li> <li><a href="/wiki/George_Francis_FitzGerald" title="George Francis FitzGerald">FitzGerald</a></li> <li><a href="/wiki/Gustav_Herglotz" title="Gustav Herglotz">Herglotz</a></li> <li><a href="/wiki/Hendrik_Lorentz" title="Hendrik Lorentz">Lorentz</a></li> <li><a href="/wiki/Henri_Poincar%C3%A9" title="Henri Poincaré">Poincaré</a></li> <li><a href="/wiki/Hermann_Minkowski" title="Hermann Minkowski">Minkowski</a></li> <li><a href="/wiki/Hippolyte_Fizeau" title="Hippolyte Fizeau">Fizeau</a></li> <li><a href="/wiki/Max_Abraham" title="Max Abraham">Abraham</a></li> <li><a href="/wiki/Max_Born" title="Max Born">Born</a></li> <li><a href="/wiki/Max_Planck" title="Max Planck">Planck</a></li> <li><a href="/wiki/Max_von_Laue" title="Max von Laue">von Laue</a></li> <li><a href="/wiki/Paul_Ehrenfest" title="Paul Ehrenfest">Ehrenfest</a></li> <li><a href="/wiki/Richard_C._Tolman" title="Richard C. Tolman">Tolman</a></li> <li><a href="/wiki/Paul_Dirac" title="Paul Dirac">Dirac</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-below hlist" style="background-color: transparent; border-color: #A2B8BF"> <ul><li><a href="/wiki/File:Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/14px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png" decoding="async" width="14" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/21px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/28px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 2x" data-file-width="530" data-file-height="600" /></a> <a href="/wiki/Portal:Physics" title="Portal:Physics">Physics portal</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <a href="/wiki/Category:Special_relativity" title="Category:Special relativity">Category</a></li></ul></td></tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Special_relativity_sidebar" title="Template:Special relativity sidebar"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Special_relativity_sidebar" title="Template talk:Special relativity sidebar"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Special_relativity_sidebar" title="Special:EditPage/Template:Special relativity sidebar"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> The speed of light in <a href="/wiki/Vacuum" title="Vacuum">vacuum</a>, commonly denoted c, is a universal <a href="/wiki/Physical_constant" title="Physical constant">physical constant</a> that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour).<a href="#cite_note-6">[Note 3]</a> According to the <a href="/wiki/Special_relativity" title="Special relativity">special theory of relativity</a>, c is the upper limit for the speed at which conventional <a href="/wiki/Matter" title="Matter">matter</a> or <a href="/wiki/Energy" title="Energy">energy</a> (and thus any <a href="/wiki/Signal" title="Signal">signal</a> carrying <a href="/wiki/Information" title="Information">information</a>) can travel through <a href="/wiki/Space#Relativity" title="Space">space</a>.<a href="#cite_note-7">[4]</a><a href="#cite_note-8">[5]</a><a href="#cite_note-9">[6]</a> All forms of <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">electromagnetic radiation</a>, including <a href="/wiki/Visible_light" class="mw-redirect" title="Visible light">visible light</a>, travel at the speed of light. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their finite speed has noticeable effects. Much <a href="/wiki/Starlight" title="Starlight">starlight</a> viewed on <a href="/wiki/Earth" title="Earth">Earth</a> is from the distant past, allowing humans to study the history of the universe by viewing distant objects. When <a href="/wiki/Data_communication" title="Data communication">communicating</a> with distant <a href="/wiki/Space_probe" class="mw-redirect" title="Space probe">space probes</a>, it can take minutes to hours for signals to travel. In <a href="/wiki/Computing" title="Computing">computing</a>, the speed of light fixes the ultimate minimum <a href="/wiki/Latency_(engineering)" title="Latency (engineering)">communication delay</a>. The speed of light can be used in <a href="/wiki/Time_of_flight" title="Time of flight">time of flight</a> measurements to measure large distances to extremely high precision. <a href="/wiki/Ole_R%C3%B8mer" title="Ole Rømer">Ole Rømer</a> first <a href="/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light" title="Rømer's determination of the speed of light">demonstrated in 1676</a> that light does not travel instantaneously by studying the apparent motion of <a href="/wiki/Jupiter" title="Jupiter">Jupiter</a>'s moon <a href="/wiki/Io_(moon)" title="Io (moon)">Io</a>. Progressively more accurate measurements of its speed came over the following centuries. In a <a href="/wiki/A_Dynamical_Theory_of_the_Electromagnetic_Field" title="A Dynamical Theory of the Electromagnetic Field">paper</a> published in 1865, <a href="/wiki/James_Clerk_Maxwell" title="James Clerk Maxwell">James Clerk Maxwell</a> proposed that light was an <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">electromagnetic wave</a> and, therefore, travelled at speed c.<a href="#cite_note-10">[7]</a> In 1905, <a href="/wiki/Albert_Einstein" title="Albert Einstein">Albert Einstein</a> postulated that the speed of light c with respect to any <a href="/wiki/Inertial_frame_of_reference" title="Inertial frame of reference">inertial frame of reference</a> is a constant and is independent of the motion of the light source.<a href="#cite_note-stachel-11">[8]</a> He explored the consequences of that postulate by deriving the <a href="/wiki/Theory_of_relativity" title="Theory of relativity">theory of relativity</a> and, in doing so, showed that the parameter c had relevance outside of the context of light and electromagnetism. <a href="/wiki/Massless_particle" title="Massless particle">Massless particles</a> and <a href="/wiki/Field_(physics)" title="Field (physics)">field</a> perturbations, such as <a href="/wiki/Gravitational_wave" title="Gravitational wave">gravitational waves</a>, also travel at speed c in vacuum. Such particles and waves travel at c regardless of the motion of the source or the inertial reference frame of the <a href="/wiki/Observer_(special_relativity)" title="Observer (special relativity)">observer</a>. Particles with nonzero <a href="/wiki/Rest_mass" class="mw-redirect" title="Rest mass">rest mass</a> can be accelerated to approach c but can never reach it, regardless of the frame of reference in which their speed is measured. In the <a href="/wiki/Theory_of_relativity" title="Theory of relativity">theory of relativity</a>, c interrelates <a href="/wiki/Spacetime" title="Spacetime">space and time</a> and appears in the famous <a href="/wiki/Mass%E2%80%93energy_equivalence" title="Mass–energy equivalence">mass–energy equivalence</a>, E = mc2.<a href="#cite_note-12">[9]</a> In some cases, objects or waves may appear to travel <a href="#Faster-than-light_observations_and_experiments">faster than light</a> (e.g., <a href="/wiki/Phase_velocities" class="mw-redirect" title="Phase velocities">phase velocities</a> of waves, <a href="/wiki/Superluminal_motion" title="Superluminal motion">the appearance of certain high-speed astronomical objects</a>, and particular <a href="/wiki/Quantum_effects" class="mw-redirect" title="Quantum effects">quantum effects</a>). The <a href="/wiki/Expansion_of_the_universe" title="Expansion of the universe">expansion of the universe</a> is understood to exceed the speed of light beyond <a href="/wiki/Hubble_volume" title="Hubble volume">a certain boundary</a>. The speed at which light propagates through <a href="/wiki/Transparency_and_translucency" title="Transparency and translucency">transparent materials</a>, such as glass or air, is less than c; similarly, the speed of <a href="/wiki/Electromagnetic_waves" class="mw-redirect" title="Electromagnetic waves">electromagnetic waves</a> in wire cables is slower than c. The ratio between c and the speed v at which light travels in a material is called the <a href="/wiki/Refractive_index" title="Refractive index">refractive index</a> n of the material (n = <style data-mw-deduplicate="TemplateStyles:r1214402035">.mw-parser-output .sfrac{white-space:nowrap}.mw-parser-output .sfrac.tion,.mw-parser-output .sfrac .tion{display:inline-block;vertical-align:-0.5em;font-size:85%;text-align:center}.mw-parser-output .sfrac .num{display:block;line-height:1em;margin:0.0em 0.1em;border-bottom:1px solid}.mw-parser-output .sfrac .den{display:block;line-height:1em;margin:0.1em 0.1em}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style>⁠c/v⁠). For example, for visible light, the refractive index of glass is typically around 1.5, meaning that light in glass travels at <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035">⁠c/1.5⁠ ≈ 200000 km/s (124000 mi/s); the <a href="/wiki/Refractive_index_of_air" class="mw-redirect" title="Refractive index of air">refractive index of air</a> for visible light is about 1.0003, so the speed of light in air is about 90 km/s (56 mi/s) slower than c. <style data-mw-deduplicate="TemplateStyles:r886046785">.mw-parser-output .toclimit-2 .toclevel-1 ul,.mw-parser-output .toclimit-3 .toclevel-2 ul,.mw-parser-output .toclimit-4 .toclevel-3 ul,.mw-parser-output .toclimit-5 .toclevel-4 ul,.mw-parser-output .toclimit-6 .toclevel-5 ul,.mw-parser-output .toclimit-7 .toclevel-6 ul{display:none}</style><div class="toclimit-3"><meta property="mw:PageProp/toc" /></div> <div class="mw-heading mw-heading2"><h2 id="Numerical_value,_notation,_and_units">Numerical value, notation, and units</h2></div> The speed of light in vacuum is usually denoted by a lowercase c, for "constant" or the Latin <a href="https://en.wiktionary.org/wiki/celeritas" class="extiw" title="wikt:celeritas">celeritas</a> (meaning 'swiftness, celerity'). In 1856, <a href="/wiki/Wilhelm_Eduard_Weber" title="Wilhelm Eduard Weber">Wilhelm Eduard Weber</a> and <a href="/wiki/Rudolf_Kohlrausch" title="Rudolf Kohlrausch">Rudolf Kohlrausch</a> had used c for a different constant that was later shown to equal √2 times the speed of light in vacuum. Historically, the symbol V was used as an alternative symbol for the speed of light, introduced by <a href="/wiki/James_Clerk_Maxwell" title="James Clerk Maxwell">James Clerk Maxwell</a> in 1865. In 1894, <a href="/wiki/Paul_Drude" title="Paul Drude">Paul Drude</a> redefined c with its modern meaning. <a href="/wiki/Albert_Einstein" title="Albert Einstein">Einstein</a> used V in his <a href="/wiki/Annus_Mirabilis_papers" class="mw-redirect" title="Annus Mirabilis papers">original German-language papers</a> on special relativity in 1905, but in 1907 he switched to c, which by then had become the standard symbol for the speed of light.<a href="#cite_note-Yc-13">[10]</a><a href="#cite_note-14">[11]</a> Sometimes c is used for the speed of waves in any material medium, and c0 for the speed of light in vacuum.<a href="#cite_note-handbook-15">[12]</a> This subscripted notation, which is endorsed in official SI literature,<a href="#cite_note-BIPM_SI_units-16">[13]</a> has the same form as related electromagnetic constants: namely, μ0 for the <a href="/wiki/Vacuum_permeability" title="Vacuum permeability">vacuum permeability</a> or magnetic constant, ε0 for the <a href="/wiki/Vacuum_permittivity" title="Vacuum permittivity">vacuum permittivity</a> or electric constant, and Z0 for the <a href="/wiki/Impedance_of_free_space" title="Impedance of free space">impedance of free space</a>. This article uses c exclusively for the speed of light in vacuum. <div class="mw-heading mw-heading3"><h3 id="Use_in_unit_systems">Use in unit systems</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Metre#Speed_of_light_definition" title="Metre">Metre § Speed of light definition</a></div> Since 1983, the constant c has been defined in the <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a> (SI) as exactly 299792458 m/s; this relationship is used to define the metre as exactly the distance that light travels in vacuum in <style data-mw-deduplicate="TemplateStyles:r1154941027">.mw-parser-output .frac{white-space:nowrap}.mw-parser-output .frac .num,.mw-parser-output .frac .den{font-size:80%;line-height:0;vertical-align:super}.mw-parser-output .frac .den{vertical-align:sub}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style>1⁄299792458 of a second. By using the value of c, as well as an accurate measurement of the second, one can thus establish a standard for the metre.<a href="#cite_note-fixes-17">[14]</a> As a <a href="/wiki/Physical_constant#Dimensional_and_dimensionless_physical_constants" title="Physical constant">dimensional physical constant</a>, the numerical value of c is different for different unit systems. For example, in <a href="/wiki/Imperial_units" title="Imperial units">imperial units</a>, the speed of light is approximately 186282 miles per second,<a href="#cite_note-imperial-18">[Note 4]</a> or roughly 1 <a href="/wiki/Foot_(unit)" title="Foot (unit)">foot</a> per nanosecond.<a href="#cite_note-nanosecond-19">[Note 5]</a><a href="#cite_note-20">[15]</a><a href="#cite_note-21">[16]</a> In branches of physics in which c appears often, such as in relativity, it is common to use systems of <a href="/wiki/Natural_units" title="Natural units">natural units</a> of measurement or the <a href="/wiki/Geometrized_unit_system" title="Geometrized unit system">geometrized unit system</a> where c = 1.<a href="#cite_note-Lawrie-22">[17]</a><a href="#cite_note-Hsu1-23">[18]</a> Using these units, c does not appear explicitly because multiplication or division by 1 does not affect the result. Its unit of <a href="/wiki/Light-second" title="Light-second">light-second</a> per second is still relevant, even if omitted. <div class="mw-heading mw-heading2"><h2 id="Fundamental_role_in_physics">Fundamental role in physics</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Special_relativity" title="Special relativity">Special relativity</a> and <a href="/wiki/One-way_speed_of_light" title="One-way speed of light">One-way speed of light</a></div> The speed at which light waves propagate in vacuum is independent both of the motion of the wave source and of the <a href="/wiki/Inertial_frame_of_reference" title="Inertial frame of reference">inertial frame of reference</a> of the observer.<a href="#cite_note-24">[Note 6]</a> This invariance of the speed of light was postulated by Einstein in 1905,<a href="#cite_note-stachel-11">[8]</a> after being motivated by <a href="/wiki/Maxwell%27s_theory_of_electromagnetism" class="mw-redirect" title="Maxwell's theory of electromagnetism">Maxwell's theory of electromagnetism</a> and the lack of evidence for motion against the <a href="/wiki/Luminiferous_aether" title="Luminiferous aether">luminiferous aether</a>.<a href="#cite_note-25">[19]</a> It has since been consistently confirmed by many experiments.<a href="#cite_note-26">[Note 7]</a> It is only possible to verify experimentally that the two-way speed of light (for example, from a source to a mirror and back again) is frame-independent, because it is impossible to measure the <a href="/wiki/One-way_speed_of_light" title="One-way speed of light">one-way speed of light</a> (for example, from a source to a distant detector) without some convention as to how clocks at the source and at the detector should be synchronized.<a href="#cite_note-Hsu2-27">[20]</a><a href="#cite_note-Zhang-28">[21]</a> By adopting <a href="/wiki/Einstein_synchronization" class="mw-redirect" title="Einstein synchronization">Einstein synchronization</a> for the clocks, the one-way speed of light becomes equal to the two-way speed of light by definition.<a href="#cite_note-Hsu2-27">[20]</a><a href="#cite_note-Zhang-28">[21]</a> The <a href="/wiki/Special_theory_of_relativity" class="mw-redirect" title="Special theory of relativity">special theory of relativity</a> explores the consequences of this invariance of c with the assumption that the laws of physics are the same in all inertial frames of reference.<a href="#cite_note-29">[22]</a><a href="#cite_note-30">[23]</a> One consequence is that c is the speed at which all massless particles and waves, including light, must travel in vacuum.<a href="#cite_note-:0-31">[24]</a><a href="#cite_note-33">[Note 8]</a> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Lorentz_factor.svg" class="mw-file-description"><img alt="γ starts at 1 when v equals zero and stays nearly constant for small v's, then it sharply curves upwards and has a vertical asymptote, diverging to positive infinity as v approaches c." src="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Lorentz_factor.svg/170px-Lorentz_factor.svg.png" decoding="async" width="170" height="172" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Lorentz_factor.svg/255px-Lorentz_factor.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/00/Lorentz_factor.svg/340px-Lorentz_factor.svg.png 2x" data-file-width="1102" data-file-height="1118" /></a><figcaption>The <a href="/wiki/Lorentz_factor" title="Lorentz factor">Lorentz factor</a> γ as a function of velocity. It starts at 1 and approaches infinity as v approaches c.</figcaption></figure> Special relativity has many counterintuitive and experimentally verified implications.<a href="#cite_note-34">[26]</a> These include the <a href="/wiki/Mass%E2%80%93energy_equivalence" title="Mass–energy equivalence">equivalence of mass and energy</a> (E = mc2), <a href="/wiki/Length_contraction" title="Length contraction">length contraction</a> (moving objects shorten),<a href="#cite_note-37">[Note 9]</a> and <a href="/wiki/Time_dilation" title="Time dilation">time dilation</a> (moving clocks run more slowly). The factor γ by which lengths contract and times dilate is known as the <a href="/wiki/Lorentz_factor" title="Lorentz factor">Lorentz factor</a> and is given by γ = (1 − v2/c2)−1/2, where v is the speed of the object. The difference of γ from 1 is negligible for speeds much slower than c, such as most everyday speeds – in which case special relativity is closely approximated by <a href="/wiki/Galilean_relativity" class="mw-redirect" title="Galilean relativity">Galilean relativity</a> – but it increases at relativistic speeds and diverges to infinity as v approaches c. For example, a time dilation factor of γ = 2 occurs at a relative velocity of 86.6% of the speed of light (v = 0.866 c). Similarly, a time dilation factor of γ = 10 occurs at 99.5% the speed of light (v = 0.995 c). The results of special relativity can be summarized by treating space and time as a unified structure known as <a href="/wiki/Spacetime" title="Spacetime">spacetime</a> (with c relating the units of space and time), and requiring that physical theories satisfy a special <a href="/wiki/Symmetry_in_physics" class="mw-redirect" title="Symmetry in physics">symmetry</a> called <a href="/wiki/Lorentz_invariance" class="mw-redirect" title="Lorentz invariance">Lorentz invariance</a>, whose mathematical formulation contains the parameter c.<a href="#cite_note-38">[29]</a> Lorentz invariance is an almost universal assumption for modern physical theories, such as <a href="/wiki/Quantum_electrodynamics" title="Quantum electrodynamics">quantum electrodynamics</a>, <a href="/wiki/Quantum_chromodynamics" title="Quantum chromodynamics">quantum chromodynamics</a>, the <a href="/wiki/Standard_Model" title="Standard Model">Standard Model</a> of <a href="/wiki/Particle_physics" title="Particle physics">particle physics</a>, and <a href="/wiki/General_relativity" title="General relativity">general relativity</a>. As such, the parameter c is ubiquitous in modern physics, appearing in many contexts that are unrelated to light. For example, general relativity predicts that c is also the <a href="/wiki/Speed_of_gravity" title="Speed of gravity">speed of gravity</a> and of <a href="/wiki/Gravitational_waves" class="mw-redirect" title="Gravitational waves">gravitational waves</a>,<a href="#cite_note-Hartle-39">[30]</a> and observations of gravitational waves have been consistent with this prediction.<a href="#cite_note-40">[31]</a> In <a href="/wiki/Non-inertial_frame" class="mw-redirect" title="Non-inertial frame">non-inertial frames</a> of reference (gravitationally curved spacetime or <a href="/wiki/Accelerated_reference_frame" class="mw-redirect" title="Accelerated reference frame">accelerated reference frames</a>), the local speed of light is constant and equal to c, but the speed of light can differ from c when measured from a remote frame of reference, depending on how measurements are extrapolated to the region.<a href="#cite_note-Gibbs1997-41">[32]</a> It is generally assumed that fundamental constants such as c have the same value throughout spacetime, meaning that they do not depend on location and do not vary with time. However, it has been suggested in various theories that the <a href="/wiki/Variable_speed_of_light" title="Variable speed of light">speed of light may have changed over time</a>.<a href="#cite_note-Ellis_Uzan-42">[33]</a><a href="#cite_note-Mota-43">[34]</a> No conclusive evidence for such changes has been found, but they remain the subject of ongoing research.<a href="#cite_note-Uzan-44">[35]</a><a href="#cite_note-Camelia-45">[36]</a> It is generally assumed that the two-way speed of light is <a href="/wiki/Isotropy" title="Isotropy">isotropic</a>, meaning that it has the same value regardless of the direction in which it is measured. Observations of the emissions from nuclear <a href="/wiki/Energy_level" title="Energy level">energy levels</a> as a function of the orientation of the emitting <a href="/wiki/Atomic_nucleus" title="Atomic nucleus">nuclei</a> in a magnetic field (see <a href="/wiki/Hughes%E2%80%93Drever_experiment" title="Hughes–Drever experiment">Hughes–Drever experiment</a>), and of rotating <a href="/wiki/Optical_resonator" class="mw-redirect" title="Optical resonator">optical resonators</a> (see <a href="/wiki/Michelson%E2%80%93Morley_experiment#Recent_experiments" title="Michelson–Morley experiment">Resonator experiments</a>) have put stringent limits on the possible two-way <a href="/wiki/Anisotropy" title="Anisotropy">anisotropy</a>.<a href="#cite_note-Herrmann-46">[37]</a><a href="#cite_note-Lang-47">[38]</a> <div class="mw-heading mw-heading3"><h3 id="Upper_limit_on_speeds">Upper limit on speeds</h3></div> According to special relativity, the energy of an object with <a href="/wiki/Rest_mass" class="mw-redirect" title="Rest mass">rest mass</a> m and speed v is given by γmc2, where γ is the Lorentz factor defined above. When v is zero, γ is equal to one, giving rise to the famous E = mc2 formula for mass–energy equivalence. The γ factor approaches infinity as v approaches c, and it would take an infinite amount of energy to accelerate an object with mass to the speed of light. The speed of light is the upper limit for the speeds of objects with positive rest mass, and individual photons cannot travel faster than the speed of light.<a href="#cite_note-48">[39]</a> This is experimentally established in many <a href="/wiki/Tests_of_relativistic_energy_and_momentum" title="Tests of relativistic energy and momentum">tests of relativistic energy and momentum</a>.<a href="#cite_note-49">[40]</a> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Relativity_of_Simultaneity.svg" class="mw-file-description"><img alt="Three pairs of coordinate axes are depicted with the same origin A; in the green frame, the x axis is horizontal and the ct axis is vertical; in the red frame, the x′ axis is slightly skewed upwards, and the ct′ axis slightly skewed rightwards, relative to the green axes; in the blue frame, the x′′ axis is somewhat skewed downwards, and the ct′′ axis somewhat skewed leftwards, relative to the green axes. A point B on the green x axis, to the left of A, has zero ct, positive ct′, and negative ct′′." src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Relativity_of_Simultaneity.svg/220px-Relativity_of_Simultaneity.svg.png" decoding="async" width="220" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Relativity_of_Simultaneity.svg/330px-Relativity_of_Simultaneity.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Relativity_of_Simultaneity.svg/440px-Relativity_of_Simultaneity.svg.png 2x" data-file-width="563" data-file-height="563" /></a><figcaption>Event A precedes B in the red frame, is simultaneous with B in the green frame, and follows B in the blue frame.</figcaption></figure> More generally, it is impossible for signals or energy to travel faster than c. One argument for this follows from the counter-intuitive implication of special relativity known as the <a href="/wiki/Relativity_of_simultaneity" title="Relativity of simultaneity">relativity of simultaneity</a>. If the spatial distance between two events A and B is greater than the time interval between them multiplied by c then there are frames of reference in which A precedes B, others in which B precedes A, and others in which they are simultaneous. As a result, if something were travelling faster than c relative to an inertial frame of reference, it would be travelling backwards in time relative to another frame, and <a href="/wiki/Causality_(physics)" title="Causality (physics)">causality</a> would be violated.<a href="#cite_note-52">[Note 10]</a><a href="#cite_note-Taylor_p74-53">[43]</a> In such a frame of reference, an "effect" could be observed before its "cause". Such a violation of causality has never been recorded,<a href="#cite_note-Zhang-28">[21]</a> and would lead to <a href="/wiki/Paradox" title="Paradox">paradoxes</a> such as the <a href="/wiki/Tachyonic_antitelephone" title="Tachyonic antitelephone">tachyonic antitelephone</a>.<a href="#cite_note-54">[44]</a> <div class="mw-heading mw-heading2"><h2 id="Faster-than-light_observations_and_experiments">Faster-than-light observations and experiments</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Faster-than-light" title="Faster-than-light">Faster-than-light</a> and <a href="/wiki/Superluminal_motion" title="Superluminal motion">Superluminal motion</a></div> There are situations in which it may seem that matter, energy, or information-carrying signal travels at speeds greater than c, but they do not. For example, as is discussed in the <a href="#In_a_medium">propagation of light in a medium</a> section below, many wave velocities can exceed c. The <a href="/wiki/Phase_velocity" title="Phase velocity">phase velocity</a> of <a href="/wiki/X-ray" title="X-ray">X-rays</a> through most glasses can routinely exceed c,<a href="#cite_note-55">[45]</a> but phase velocity does not determine the velocity at which waves convey information.<a href="#cite_note-56">[46]</a> If a laser beam is swept quickly across a distant object, the spot of light can move faster than c, although the initial movement of the spot is delayed because of the time it takes light to get to the distant object at the speed c. However, the only physical entities that are moving are the laser and its emitted light, which travels at the speed c from the laser to the various positions of the spot. Similarly, a shadow projected onto a distant object can be made to move faster than c, after a delay in time.<a href="#cite_note-57">[47]</a> In neither case does any matter, energy, or information travel faster than light.<a href="#cite_note-Gibbs-58">[48]</a> The rate of change in the distance between two objects in a frame of reference with respect to which both are moving (their <a href="/wiki/Faster-than-light#Closing_speeds" title="Faster-than-light">closing speed</a>) may have a value in excess of c. However, this does not represent the speed of any single object as measured in a single inertial frame.<a href="#cite_note-Gibbs-58">[48]</a> Certain quantum effects appear to be transmitted instantaneously and therefore faster than c, as in the <a href="/wiki/EPR_paradox" class="mw-redirect" title="EPR paradox">EPR paradox</a>. An example involves the <a href="/wiki/Quantum_state" title="Quantum state">quantum states</a> of two particles that can be <a href="/wiki/Quantum_entanglement" title="Quantum entanglement">entangled</a>. Until either of the particles is observed, they exist in a <a href="/wiki/Quantum_superposition" title="Quantum superposition">superposition</a> of two quantum states. If the particles are separated and one particle's quantum state is observed, the other particle's quantum state is determined instantaneously. However, it is impossible to control which quantum state the first particle will take on when it is observed, so information cannot be transmitted in this manner.<a href="#cite_note-Gibbs-58">[48]</a><a href="#cite_note-59">[49]</a> Another quantum effect that predicts the occurrence of faster-than-light speeds is called the <a href="/wiki/Hartman_effect" title="Hartman effect">Hartman effect</a>: under certain conditions the time needed for a <a href="/wiki/Virtual_particle" title="Virtual particle">virtual particle</a> to <a href="/wiki/Quantum_tunnelling" title="Quantum tunnelling">tunnel</a> through a barrier is constant, regardless of the thickness of the barrier.<a href="#cite_note-Muga-60">[50]</a><a href="#cite_note-Recami-61">[51]</a> This could result in a virtual particle crossing a large gap faster than light. However, no information can be sent using this effect.<a href="#cite_note-Wynne-62">[52]</a> So-called <a href="/wiki/Superluminal_motion" title="Superluminal motion">superluminal motion</a> is seen in certain astronomical objects,<a href="#cite_note-63">[53]</a> such as the <a href="/wiki/Relativistic_jet" class="mw-redirect" title="Relativistic jet">relativistic jets</a> of <a href="/wiki/Radio_galaxy" title="Radio galaxy">radio galaxies</a> and <a href="/wiki/Quasar" title="Quasar">quasars</a>. However, these jets are not moving at speeds in excess of the speed of light: the apparent superluminal motion is a <a href="/wiki/Graphical_projection" class="mw-redirect" title="Graphical projection">projection</a> effect caused by objects moving near the speed of light and approaching Earth at a small angle to the line of sight: since the light which was emitted when the jet was farther away took longer to reach the Earth, the time between two successive observations corresponds to a longer time between the instants at which the light rays were emitted.<a href="#cite_note-64">[54]</a> A 2011 experiment where <a href="/wiki/Faster-than-light_neutrino_anomaly" class="mw-redirect" title="Faster-than-light neutrino anomaly">neutrinos were observed to travel faster than light</a> turned out to be due to experimental error.<a href="#cite_note-nature1204-65">[55]</a><a href="#cite_note-66">[56]</a> In models of the <a href="/wiki/Expansion_of_the_universe" title="Expansion of the universe">expanding universe</a>, the farther galaxies are from each other, the faster they drift apart. For example, galaxies far away from Earth are inferred to be moving away from the Earth with speeds proportional to their distances. Beyond a boundary called the <a href="/wiki/Hubble_sphere" class="mw-redirect" title="Hubble sphere">Hubble sphere</a>, the rate at which their distance from Earth increases becomes greater than the speed of light.<a href="#cite_note-Harrison-67">[57]</a> These recession rates, defined as the increase in <a href="/wiki/Comoving_and_proper_distances" title="Comoving and proper distances">proper distance</a> per <a href="/wiki/Cosmological_time" class="mw-redirect" title="Cosmological time">cosmological time</a>, are not velocities in a relativistic sense. Faster-than-light cosmological recession speeds are only a <a href="/wiki/Coordinate_conditions" title="Coordinate conditions">coordinate</a> artifact. <div class="mw-heading mw-heading2"><h2 id="Propagation_of_light">Propagation of light</h2></div> In <a href="/wiki/Classical_physics" title="Classical physics">classical physics</a>, light is described as a type of <a href="/wiki/Electromagnetic_wave" class="mw-redirect" title="Electromagnetic wave">electromagnetic wave</a>. The classical behaviour of the <a href="/wiki/Electromagnetic_field" title="Electromagnetic field">electromagnetic field</a> is described by <a href="/wiki/Maxwell%27s_equations" title="Maxwell's equations">Maxwell's equations</a>, which predict that the speed c with which electromagnetic waves (such as light) propagate in vacuum is related to the distributed capacitance and inductance of vacuum, otherwise respectively known as the <a href="/wiki/Electric_constant" class="mw-redirect" title="Electric constant">electric constant</a> ε0 and the <a href="/wiki/Magnetic_constant" class="mw-redirect" title="Magnetic constant">magnetic constant</a> μ0, by the equation<a href="#cite_note-68">[58]</a> <dl><dd><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c={\frac {1}{\sqrt {\varepsilon _{0}\mu _{0}}}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>c</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <msqrt> <msub> <mi>ε</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msub> <msub> <mi>μ</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msub> </msqrt> </mfrac> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c={\frac {1}{\sqrt {\varepsilon _{0}\mu _{0}}}}.}</annotation> </semantics> </math><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b468f8919e0ee4549d40346eeda5bef3761f0bfc" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.838ex; width:12.118ex; height:6.176ex;" alt="{\displaystyle c={\frac {1}{\sqrt {\varepsilon _{0}\mu _{0}}}}.}"></dd></dl> In modern <a href="/wiki/Quantum_physics" class="mw-redirect" title="Quantum physics">quantum physics</a>, the electromagnetic field is described by the theory of <a href="/wiki/Quantum_electrodynamics" title="Quantum electrodynamics">quantum electrodynamics</a> (QED). In this theory, light is described by the fundamental excitations (or quanta) of the electromagnetic field, called <a href="/wiki/Photon" title="Photon">photons</a>. In QED, photons are <a href="/wiki/Massless_particle" title="Massless particle">massless particles</a> and thus, according to special relativity, they travel at the speed of light in vacuum.<a href="#cite_note-:0-31">[24]</a> Extensions of QED in which the photon has a mass have been considered. In such a theory, its speed would depend on its frequency, and the invariant speed c of special relativity would then be the upper limit of the speed of light in vacuum.<a href="#cite_note-Gibbs1997-41">[32]</a> No variation of the speed of light with frequency has been observed in rigorous testing, putting stringent limits on the mass of the photon.<a href="#cite_note-69">[59]</a> The limit obtained depends on the model used: if the massive photon is described by <a href="/wiki/Proca_action" title="Proca action">Proca theory</a>,<a href="#cite_note-adelberger-70">[60]</a> the experimental upper bound for its mass is about 10−57 <a href="/wiki/Gram" title="Gram">grams</a>;<a href="#cite_note-Sidharth-71">[61]</a> if photon mass is generated by a <a href="/wiki/Higgs_mechanism" title="Higgs mechanism">Higgs mechanism</a>, the experimental upper limit is less sharp, m ≤ 10−14 <a href="/wiki/Electronvolt#Mass" title="Electronvolt">eV/c2</a>  (roughly 2 × 10−47 g).<a href="#cite_note-adelberger-70">[60]</a> Another reason for the speed of light to vary with its frequency would be the failure of special relativity to apply to arbitrarily small scales, as predicted by some proposed theories of <a href="/wiki/Quantum_gravity" title="Quantum gravity">quantum gravity</a>. In 2009, the observation of <a href="/wiki/Gamma-ray_burst" title="Gamma-ray burst">gamma-ray burst</a> <a href="/w/index.php?title=GRB_090510&action=edit&redlink=1" class="new" title="GRB 090510 (page does not exist)">GRB 090510</a> found no evidence for a dependence of photon speed on energy, supporting tight constraints in specific models of spacetime quantization on how this speed is affected by photon energy for energies approaching the <a href="/wiki/Planck_scale" class="mw-redirect" title="Planck scale">Planck scale</a>.<a href="#cite_note-72">[62]</a> <div class="mw-heading mw-heading3"><h3 id="In_a_medium">In a medium</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Refractive_index" title="Refractive index">Refractive index</a></div> In a medium, light usually does not propagate at a speed equal to c; further, different types of light wave will travel at different speeds. The speed at which the individual crests and troughs of a <a href="/wiki/Plane_wave" title="Plane wave">plane wave</a> (a wave filling the whole space, with only one <a href="/wiki/Frequency" title="Frequency">frequency</a>) propagate is called the <a href="/wiki/Phase_velocity" title="Phase velocity">phase velocity</a> vp. A physical signal with a finite extent (a pulse of light) travels at a different speed. The overall <a href="/wiki/Envelope_(waves)" title="Envelope (waves)">envelope</a> of the pulse travels at the <a href="/wiki/Group_velocity" title="Group velocity">group velocity</a> vg, and its earliest part travels at the <a href="/wiki/Front_velocity" title="Front velocity">front velocity</a> vf.<a href="#cite_note-Milonni-73">[63]</a> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Frontgroupphase.gif" class="mw-file-description"><img alt="A modulated wave moves from left to right. There are three points marked with a dot: A blue dot at a node of the carrier wave, a green dot at the maximum of the envelope, and a red dot at the front of the envelope." src="//upload.wikimedia.org/wikipedia/commons/thumb/2/27/Frontgroupphase.gif/220px-Frontgroupphase.gif" decoding="async" width="220" height="136" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/27/Frontgroupphase.gif/330px-Frontgroupphase.gif 1.5x, //upload.wikimedia.org/wikipedia/commons/2/27/Frontgroupphase.gif 2x" data-file-width="440" data-file-height="272" /></a><figcaption>The blue dot moves at the speed of the ripples, the phase velocity; the green dot moves with the speed of the envelope, the group velocity; and the red dot moves with the speed of the foremost part of the pulse, the front velocity.</figcaption></figure> The phase velocity is important in determining how a light wave travels through a material or from one material to another. It is often represented in terms of a refractive index. The refractive index of a material is defined as the ratio of c to the phase velocity vp in the material: larger indices of refraction indicate lower speeds. The refractive index of a material may depend on the light's frequency, intensity, <a href="/wiki/Polarization_(waves)" title="Polarization (waves)">polarization</a>, or direction of propagation; in many cases, though, it can be treated as a material-dependent constant. The <a href="/wiki/Refractive_index_of_air" class="mw-redirect" title="Refractive index of air">refractive index of air</a> is approximately 1.0003.<a href="#cite_note-Podesta-74">[64]</a> Denser media, such as <a href="/wiki/Optical_properties_of_water_and_ice" title="Optical properties of water and ice">water</a>,<a href="#cite_note-75">[65]</a> <a href="/wiki/Glass" title="Glass">glass</a>,<a href="#cite_note-76">[66]</a> and <a href="/wiki/Material_properties_of_diamond#Optical_properties" title="Material properties of diamond">diamond</a>,<a href="#cite_note-77">[67]</a> have refractive indexes of around 1.3, 1.5 and 2.4, respectively, for visible light. In exotic materials like <a href="/wiki/Bose%E2%80%93Einstein_condensate" title="Bose–Einstein condensate">Bose–Einstein condensates</a> near <a href="/wiki/Absolute_zero" title="Absolute zero">absolute zero</a>, the effective speed of light may be only a few metres per second. However, this represents absorption and re-radiation delay between atoms, as do all slower-than-c speeds in material substances. As an extreme example of light "slowing" in matter, two independent teams of physicists claimed to bring light to a "complete standstill" by passing it through a Bose–Einstein condensate of the element <a href="/wiki/Rubidium" title="Rubidium">rubidium</a>. The popular description of light being "stopped" in these experiments refers only to light being stored in the excited states of atoms, then re-emitted at an arbitrarily later time, as stimulated by a second laser pulse. During the time it had "stopped", it had ceased to be light. This type of behaviour is generally microscopically true of all transparent media which "slow" the speed of light.<a href="#cite_note-78">[68]</a> In transparent materials, the refractive index generally is greater than 1, meaning that the phase velocity is less than c. In other materials, it is possible for the refractive index to become smaller than 1 for some frequencies; in some exotic materials it is even possible for the index of refraction to become negative.<a href="#cite_note-79">[69]</a> The requirement that causality is not violated implies that the <a href="/wiki/Real_and_imaginary_parts" class="mw-redirect" title="Real and imaginary parts">real and imaginary parts</a> of the <a href="/wiki/Dielectric_constant" class="mw-redirect" title="Dielectric constant">dielectric constant</a> of any material, corresponding respectively to the index of refraction and to the <a href="/wiki/Attenuation_coefficient" title="Attenuation coefficient">attenuation coefficient</a>, are linked by the <a href="/wiki/Kramers%E2%80%93Kronig_relation" class="mw-redirect" title="Kramers–Kronig relation">Kramers–Kronig relations</a>.<a href="#cite_note-80">[70]</a><a href="#cite_note-81">[71]</a> In practical terms, this means that in a material with refractive index less than 1, the wave will be absorbed quickly.<a href="#cite_note-82">[72]</a> A pulse with different group and phase velocities (which occurs if the phase velocity is not the same for all the frequencies of the pulse) smears out over time, a process known as <a href="/wiki/Dispersion_(optics)" title="Dispersion (optics)">dispersion</a>. Certain materials have an exceptionally low (or even zero) group velocity for light waves, a phenomenon called <a href="/wiki/Slow_light" title="Slow light">slow light</a>.<a href="#cite_note-83">[73]</a> The opposite, group velocities exceeding c, was proposed theoretically in 1993 and achieved experimentally in 2000.<a href="#cite_note-84">[74]</a> It should even be possible for the group velocity to become infinite or negative, with pulses travelling instantaneously or backwards in time.<a href="#cite_note-Milonni-73">[63]</a> None of these options allow information to be transmitted faster than c. It is impossible to transmit information with a light pulse any faster than the speed of the earliest part of the pulse (the front velocity). It can be shown that this is (under certain assumptions) always equal to c.<a href="#cite_note-Milonni-73">[63]</a> <div style="clear:both;" class=""></div> It is possible for a particle to travel through a medium faster than the phase velocity of light in that medium (but still slower than c). When a <a href="/wiki/Charged_particle" title="Charged particle">charged particle</a> does that in a <a href="/wiki/Dielectric" title="Dielectric">dielectric</a> material, the electromagnetic equivalent of a <a href="/wiki/Shock_wave" title="Shock wave">shock wave</a>, known as <a href="/wiki/Cherenkov_radiation" title="Cherenkov radiation">Cherenkov radiation</a>, is emitted.<a href="#cite_note-85">[75]</a> <div class="mw-heading mw-heading2"><h2 id="Practical_effects_of_finiteness">Practical effects of finiteness</h2></div> The speed of light is of relevance to <a href="/wiki/Telecommunications" title="Telecommunications">telecommunications</a>: the one-way and <a href="/wiki/Round-trip_delay_time" class="mw-redirect" title="Round-trip delay time">round-trip delay time</a> are greater than zero. This applies from small to astronomical scales. On the other hand, some techniques depend on the finite speed of light, for example in distance measurements. <div class="mw-heading mw-heading3"><h3 id="Small_scales">Small scales</h3></div> In <a href="/wiki/Computer" title="Computer">computers</a>, the speed of light imposes a limit on how quickly data can be sent between <a href="/wiki/Central_processing_unit" title="Central processing unit">processors</a>. If a processor operates at 1 <a href="/wiki/Gigahertz" class="mw-redirect" title="Gigahertz">gigahertz</a>, a signal can travel only a maximum of about 30 centimetres (1 ft) in a single clock cycle – in practice, this distance is even shorter since the <a href="/wiki/Printed_circuit_board" title="Printed circuit board">printed circuit board</a> refracts and slows down signals. Processors must therefore be placed close to each other, as well as <a href="/wiki/Computer_memory" title="Computer memory">memory</a> chips, to minimize communication latencies, and care must be exercised when routing wires between them to ensure <a href="/wiki/Signal_integrity" title="Signal integrity">signal integrity</a>. If clock frequencies continue to increase, the speed of light may eventually become a limiting factor for the internal design of single <a href="/wiki/Integrated_circuit" title="Integrated circuit">chips</a>.<a href="#cite_note-processorlimit-86">[76]</a><a href="#cite_note-processorlimit2-87">[77]</a> <div class="mw-heading mw-heading3"><h3 id="Large_distances_on_Earth">Large distances on Earth</h3></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><audio id="mwe_player_0" controls="" preload="none" data-mw-tmh="" class="mw-file-element" width="220" style="width:220px;" data-durationhint="4" data-mwtitle="Light_world_trip.ogg" data-mwprovider="wikimediacommons" resource="/wiki/File:Light_world_trip.ogg"><source src="//upload.wikimedia.org/wikipedia/commons/a/a1/Light_world_trip.ogg" type="audio/ogg; codecs="vorbis"" data-width="0" data-height="0" /><source src="//upload.wikimedia.org/wikipedia/commons/transcoded/a/a1/Light_world_trip.ogg/Light_world_trip.ogg.mp3" type="audio/mpeg" data-transcodekey="mp3" data-width="0" data-height="0" /></audio><figcaption>Acoustic representation of the speed of light, at every beep the light makes a full circle around the equator</figcaption></figure> Given that the equatorial circumference of the Earth is about 40075 km and that c is about 300000 km/s, the theoretical shortest time for a piece of information to travel half the globe along the surface is about 67 milliseconds. When light is traveling in <a href="/wiki/Optical_fibre" class="mw-redirect" title="Optical fibre">optical fibre</a> (a <a href="/wiki/Transparency_and_translucency" title="Transparency and translucency">transparent material</a>) the actual transit time is longer, in part because the speed of light is slower by about 35% in optical fibre, depending on its refractive index n.<a href="#cite_note-89">[Note 11]</a> Straight lines are rare in global communications and the travel time increases when signals pass through electronic switches or signal regenerators.<a href="#cite_note-90">[79]</a> Although this distance is largely irrelevant for most applications, latency becomes important in fields such as <a href="/wiki/High-frequency_trading" title="High-frequency trading">high-frequency trading</a>, where traders seek to gain minute advantages by delivering their trades to exchanges fractions of a second ahead of other traders. For example, traders have been switching to <a href="/wiki/Microwave" title="Microwave">microwave</a> communications between trading hubs, because of the advantage which radio waves travelling at near to the speed of light through air have over comparatively slower <a href="/wiki/Fibre_optic" class="mw-redirect" title="Fibre optic">fibre optic</a> signals.<a href="#cite_note-91">[80]</a><a href="#cite_note-92">[81]</a> <div class="mw-heading mw-heading3"><h3 id="Spaceflight_and_astronomy">Spaceflight and astronomy</h3></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Earth_and_Moon_speed_of_light_by_James_O%27Donoghue.gif" class="mw-file-description"><img alt="The diameter of the moon is about one quarter of that of Earth, and their distance is about thirty times the diameter of Earth. A beam of light starts from the Earth and reaches the Moon in about a second and a quarter." src="//upload.wikimedia.org/wikipedia/commons/9/9d/Earth_and_Moon_speed_of_light_by_James_O%27Donoghue.gif" decoding="async" width="646" height="122" class="mw-file-element" data-file-width="646" data-file-height="122" /></a><figcaption>A beam of light is depicted travelling between the Earth and the Moon in the time it takes a light pulse to move between them: 1.255 seconds at their mean orbital (surface-to-surface) distance. The relative sizes and separation of the Earth–Moon system are shown to scale.</figcaption></figure> Similarly, communications between the Earth and spacecraft are not instantaneous. There is a brief delay from the source to the receiver, which becomes more noticeable as distances increase. This delay was significant for communications between <a href="/wiki/Mission_Control_Center" class="mw-redirect" title="Mission Control Center">ground control</a> and <a href="/wiki/Apollo_8" title="Apollo 8">Apollo 8</a> when it became the first crewed spacecraft to orbit the <a href="/wiki/Moon" title="Moon">Moon</a>: for every question, the ground control station had to wait at least three seconds for the answer to arrive.<a href="#cite_note-93">[82]</a> The communications delay between Earth and <a href="/wiki/Mars" title="Mars">Mars</a> can vary between five and twenty minutes depending upon the relative positions of the two planets. As a consequence of this, if a robot on the surface of Mars were to encounter a problem, its human controllers would not be aware of it until approximately 4–24 minutes later. It would then take a further 4–24 minutes for commands to travel from Earth to Mars.<a href="#cite_note-94">[83]</a><a href="#cite_note-95">[84]</a> Receiving light and other signals from distant astronomical sources takes much longer. For example, it takes 13 billion (13×109) years for light to travel to Earth from the faraway galaxies viewed in the <a href="/wiki/Hubble_Ultra-Deep_Field" title="Hubble Ultra-Deep Field">Hubble Ultra-Deep Field</a> images.<a href="#cite_note-Hubble-96">[85]</a><a href="#cite_note-97">[86]</a> Those photographs, taken today, capture images of the galaxies as they appeared 13 billion years ago, when the universe was less than a billion years old.<a href="#cite_note-Hubble-96">[85]</a> The fact that more distant objects appear to be younger, due to the finite speed of light, allows astronomers to infer the <a href="/wiki/Evolution_of_stars" class="mw-redirect" title="Evolution of stars">evolution of stars</a>, <a href="/wiki/Galaxy_formation_and_evolution" title="Galaxy formation and evolution">of galaxies</a>, and <a href="/wiki/History_of_the_universe" class="mw-redirect" title="History of the universe">of the universe</a> itself.<a href="#cite_note-98">[87]</a> Astronomical distances are sometimes expressed in <a href="/wiki/Light-year" title="Light-year">light-years</a>, especially in <a href="/wiki/Popular_science" title="Popular science">popular science</a> publications and media.<a href="#cite_note-99">[88]</a> A light-year is the distance light travels in one <a href="/wiki/Julian_year_(astronomy)" title="Julian year (astronomy)">Julian year</a>, around 9461 billion kilometres, 5879 billion miles, or 0.3066 <a href="/wiki/Parsec" title="Parsec">parsecs</a>. In round figures, a light year is nearly 10 trillion kilometres or nearly 6 trillion miles. <a href="/wiki/Proxima_Centauri" title="Proxima Centauri">Proxima Centauri</a>, the closest star to Earth after the Sun, is around 4.2 light-years away.<a href="#cite_note-starchild-100">[89]</a> <div class="mw-heading mw-heading3"><h3 id="Distance_measurement">Distance measurement</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Distance_measurement" class="mw-redirect" title="Distance measurement">Distance measurement</a></div> <a href="/wiki/Radar" title="Radar">Radar</a> systems measure the distance to a target by the time it takes a radio-wave pulse to return to the radar antenna after being reflected by the target: the distance to the target is half the round-trip <a href="/wiki/Radar#Transit_time" title="Radar">transit time</a> multiplied by the speed of light. A <a href="/wiki/Global_Positioning_System" title="Global Positioning System">Global Positioning System</a> (GPS) receiver measures its distance to <a href="/wiki/GPS_satellites" class="mw-redirect" title="GPS satellites">GPS satellites</a> based on how long it takes for a radio signal to arrive from each satellite, and from these distances calculates the receiver's position. Because light travels about 300000 kilometres (186000 miles) in one second, these measurements of small fractions of a second must be very precise. The <a href="/wiki/Lunar_Laser_Ranging_experiment" class="mw-redirect" title="Lunar Laser Ranging experiment">Lunar Laser Ranging experiment</a>, <a href="/wiki/Radar_astronomy" title="Radar astronomy">radar astronomy</a> and the <a href="/wiki/Deep_Space_Network" class="mw-redirect" title="Deep Space Network">Deep Space Network</a> determine distances to the Moon,<a href="#cite_note-science265_5171_482-101">[90]</a> planets<a href="#cite_note-cm26_181-102">[91]</a> and spacecraft,<a href="#cite_note-pieee95_11_2202-103">[92]</a> respectively, by measuring round-trip transit times. <div class="mw-heading mw-heading2"><h2 id="Measurement">Measurement</h2></div> There are different ways to determine the value of c. One way is to measure the actual speed at which light waves propagate, which can be done in various astronomical and Earth-based setups. It is also possible to determine c from other physical laws where it appears, for example, by determining the values of the electromagnetic constants <a href="/wiki/Relative_permittivity" title="Relative permittivity">ε0</a> and <a href="/wiki/Permeability_(electromagnetism)" title="Permeability (electromagnetism)">μ0</a> and using their relation to c. Historically, the most accurate results have been obtained by separately determining the frequency and wavelength of a light beam, with their product equalling c. This is described in more detail in the <a href="#Interferometry">"Interferometry" section</a> below. In 1983 the metre was defined as "the length of the path travelled by light in vacuum during a time interval of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027">1⁄299792458 of a second",<a href="#cite_note-Resolution_1-104">[93]</a> fixing the value of the speed of light at 299792458 m/s by definition, as <a href="#Increased_accuracy_of_c_and_redefinition_of_the_metre_and_second">described below</a>. Consequently, accurate measurements of the speed of light yield an accurate realization of the metre rather than an accurate value of c. <div class="mw-heading mw-heading3"><h3 id="Astronomical_measurements">Astronomical measurements</h3></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Io_eclipse_speed_of_light_measurement.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Io_eclipse_speed_of_light_measurement.svg/440px-Io_eclipse_speed_of_light_measurement.svg.png" decoding="async" width="440" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Io_eclipse_speed_of_light_measurement.svg/660px-Io_eclipse_speed_of_light_measurement.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/70/Io_eclipse_speed_of_light_measurement.svg/880px-Io_eclipse_speed_of_light_measurement.svg.png 2x" data-file-width="512" data-file-height="256" /></a><figcaption>Measurement of the speed of light from the time it takes Io to orbit Jupiter, using eclipses of Io by Jupiter's shadow to precisely measure its orbit.</figcaption></figure> <a href="/wiki/Outer_space" title="Outer space">Outer space</a> is a convenient setting for measuring the speed of light because of its large scale and nearly perfect <a href="/wiki/Vacuum" title="Vacuum">vacuum</a>. Typically, one measures the time needed for light to traverse some reference distance in the <a href="/wiki/Solar_System" title="Solar System">Solar System</a>, such as the <a href="/wiki/Radius" title="Radius">radius</a> of the Earth's orbit. Historically, such measurements could be made fairly accurately, compared to how accurately the length of the reference distance is known in Earth-based units. <a href="/wiki/Ole_R%C3%B8mer" title="Ole Rømer">Ole Rømer</a> used an astronomical measurement to make <a href="/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light" title="Rømer's determination of the speed of light">the first quantitative estimate of the speed of light</a> in the year 1676.<a href="#cite_note-cohen-105">[94]</a><a href="#cite_note-roemer-106">[95]</a> When measured from Earth, the periods of moons orbiting a distant planet are shorter when the Earth is approaching the planet than when the Earth is receding from it. The difference is small, but the cumulative time becomes significant when measured over months. The distance travelled by light from the planet (or its moon) to Earth is shorter when the Earth is at the point in its orbit that is closest to its planet than when the Earth is at the farthest point in its orbit, the difference in distance being the <a href="/wiki/Diameter" title="Diameter">diameter</a> of the Earth's orbit around the Sun. The observed change in the moon's orbital period is caused by the difference in the time it takes light to traverse the shorter or longer distance. Rømer observed this effect for <a href="/wiki/Jupiter" title="Jupiter">Jupiter</a>'s innermost major moon Io and deduced that light takes 22 minutes to cross the diameter of the Earth's orbit.<a href="#cite_note-cohen-105">[94]</a> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:SoL_Aberration.svg" class="mw-file-description"><img alt="A star emits a light ray that hits the objective of a telescope. While the light travels down the telescope to its eyepiece, the telescope moves to the right. For the light to stay inside the telescope, the telescope must be tilted to the right, causing the distant source to appear at a different location to the right." src="//upload.wikimedia.org/wikipedia/commons/thumb/8/82/SoL_Aberration.svg/170px-SoL_Aberration.svg.png" decoding="async" width="170" height="199" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/82/SoL_Aberration.svg/255px-SoL_Aberration.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/82/SoL_Aberration.svg/340px-SoL_Aberration.svg.png 2x" data-file-width="420" data-file-height="492" /></a><figcaption>Aberration of light: light from a distant source appears to be from a different location for a moving telescope due to the finite speed of light.</figcaption></figure> Another method is to use the <a href="/wiki/Aberration_of_light" class="mw-redirect" title="Aberration of light">aberration of light</a>, discovered and explained by <a href="/wiki/James_Bradley" title="James Bradley">James Bradley</a> in the 18th century.<a href="#cite_note-Bradley1729-107">[96]</a> This effect results from the <a href="/wiki/Vector_addition" class="mw-redirect" title="Vector addition">vector addition</a> of the velocity of light arriving from a distant source (such as a star) and the velocity of its observer (see diagram on the right). A moving observer thus sees the light coming from a slightly different direction and consequently sees the source at a position shifted from its original position. Since the direction of the Earth's velocity changes continuously as the Earth orbits the Sun, this effect causes the apparent position of stars to move around. From the angular difference in the position of stars (maximally 20.5 <a href="/wiki/Arcsecond" class="mw-redirect" title="Arcsecond">arcseconds</a>)<a href="#cite_note-108">[97]</a> it is possible to express the speed of light in terms of the Earth's velocity around the Sun, which with the known length of a year can be converted to the time needed to travel from the Sun to the Earth. In 1729, Bradley used this method to derive that light travelled 10210 times faster than the Earth in its orbit (the modern figure is 10066 times faster) or, equivalently, that it would take light 8 minutes 12 seconds to travel from the Sun to the Earth.<a href="#cite_note-Bradley1729-107">[96]</a> <div class="mw-heading mw-heading4"><h4 id="Astronomical_unit">Astronomical unit</h4></div> An astronomical unit (AU) is approximately the average distance between the Earth and Sun. It was redefined in 2012 as exactly 149597870700 m.<a href="#cite_note-AU_redef-109">[98]</a><a href="#cite_note-110">[99]</a> Previously the AU was not based on the <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a> but in terms of the gravitational force exerted by the Sun in the framework of classical mechanics.<a href="#cite_note-112">[Note 12]</a> The current definition uses the recommended value in metres for the previous definition of the astronomical unit, which was determined by measurement.<a href="#cite_note-AU_redef-109">[98]</a> This redefinition is analogous to that of the metre and likewise has the effect of fixing the speed of light to an exact value in astronomical units per second (via the exact speed of light in metres per second).<a href="#cite_note-113">[101]</a> Previously, the inverse of c expressed in seconds per astronomical unit was measured by comparing the time for radio signals to reach different spacecraft in the Solar System, with their position calculated from the gravitational effects of the Sun and various planets. By combining many such measurements, a <a href="/wiki/Best_fit" class="mw-redirect" title="Best fit">best fit</a> value for the light time per unit distance could be obtained. For example, in 2009, the best estimate, as approved by the <a href="/wiki/International_Astronomical_Union" title="International Astronomical Union">International Astronomical Union</a> (IAU), was:<a href="#cite_note-114">[102]</a><a href="#cite_note-IAU-115">[103]</a> <dl><dd>light time for unit distance: tau = 499.004783836(10) s,</dd> <dd>c = 0.00200398880410(4) AU/s = 173.144632674(3) AU/d.</dd></dl> The relative uncertainty in these measurements is 0.02 parts per billion (2×10−11), equivalent to the uncertainty in Earth-based measurements of length by interferometry.<a href="#cite_note-116">[104]</a> Since the metre is defined to be the length travelled by light in a certain time interval, the measurement of the light time in terms of the previous definition of the astronomical unit can also be interpreted as measuring the length of an AU (old definition) in metres.<a href="#cite_note-117">[Note 13]</a> <div class="mw-heading mw-heading3"><h3 id="Time_of_flight_techniques">Time of flight techniques</h3></div> <figure class="mw-halign-center" typeof="mw:File/Thumb"><a href="/wiki/File:Michelson_speed_of_light_measurement_1930.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Michelson_speed_of_light_measurement_1930.jpg/600px-Michelson_speed_of_light_measurement_1930.jpg" decoding="async" width="600" height="241" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Michelson_speed_of_light_measurement_1930.jpg/900px-Michelson_speed_of_light_measurement_1930.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/e/e8/Michelson_speed_of_light_measurement_1930.jpg 2x" data-file-width="1168" data-file-height="470" /></a><figcaption>One of the last and most accurate time of flight measurements, Michelson, Pease and Pearson's 1930–1935 experiment used a rotating mirror and a one-mile (1.6 km) long vacuum chamber which the light beam traversed 10 times. It achieved accuracy of ±11 km/s.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Fizeau-int.svg" class="mw-file-description"><img alt="A light ray passes horizontally through a half-mirror and a rotating cog wheel, is reflected back by a mirror, passes through the cog wheel, and is reflected by the half-mirror into a monocular." src="//upload.wikimedia.org/wikipedia/commons/thumb/6/68/Fizeau-int.svg/220px-Fizeau-int.svg.png" decoding="async" width="220" height="183" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/68/Fizeau-int.svg/330px-Fizeau-int.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/68/Fizeau-int.svg/440px-Fizeau-int.svg.png 2x" data-file-width="661" data-file-height="550" /></a><figcaption>Diagram of the <a href="/wiki/Fizeau%27s_measurement_of_the_speed_of_light_in_air" title="Fizeau's measurement of the speed of light in air">Fizeau apparatus</a>:<style data-mw-deduplicate="TemplateStyles:r1256394559">.mw-parser-output figure[typeof="mw:File/Thumb"] .image-key>ol{margin-left:1.3em;margin-top:0}.mw-parser-output figure[typeof="mw:File/Thumb"] .image-key>ul{margin-top:0}.mw-parser-output figure[typeof="mw:File/Thumb"] .image-key li{page-break-inside:avoid;break-inside:avoid-column}@media(min-width:300px){.mw-parser-output figure[typeof="mw:File/Thumb"] .image-key,.mw-parser-output figure[typeof="mw:File/Thumb"] .image-key-wide{column-count:2}.mw-parser-output figure[typeof="mw:File/Thumb"] .image-key-narrow{column-count:1}}@media(min-width:450px){.mw-parser-output figure[typeof="mw:File/Thumb"] .image-key-wide{column-count:3}}</style><div class="image-key"><ol><li>Light source</li><li>Beam-splitting semi-transparent mirror</li><li>Toothed wheel-breaker of the light beam</li><li>Remote mirror</li><li>Telescopic tube</li></ol></div></figcaption></figure> A method of measuring the speed of light is to measure the time needed for light to travel to a mirror at a known distance and back. This is the working principle behind experiments by <a href="/wiki/Hippolyte_Fizeau" title="Hippolyte Fizeau">Hippolyte Fizeau</a> and <a href="/wiki/L%C3%A9on_Foucault" title="Léon Foucault">Léon Foucault</a>. The <a href="/wiki/Fizeau%27s_measurement_of_the_speed_of_light_in_air" title="Fizeau's measurement of the speed of light in air">setup as used by Fizeau</a> consists of a beam of light directed at a mirror 8 kilometres (5 mi) away. On the way from the source to the mirror, the beam passes through a rotating cogwheel. At a certain rate of rotation, the beam passes through one gap on the way out and another on the way back, but at slightly higher or lower rates, the beam strikes a tooth and does not pass through the wheel. Knowing the distance between the wheel and the mirror, the number of teeth on the wheel, and the rate of rotation, the speed of light can be calculated.<a href="#cite_note-How-118">[105]</a> The <a href="/wiki/Foucault%27s_measurements_of_the_speed_of_light" title="Foucault's measurements of the speed of light">method of Foucault</a> replaces the cogwheel with a rotating mirror. Because the mirror keeps rotating while the light travels to the distant mirror and back, the light is reflected from the rotating mirror at a different angle on its way out than it is on its way back. From this difference in angle, the known speed of rotation and the distance to the distant mirror the speed of light may be calculated.<a href="#cite_note-119">[106]</a> Foucault used this apparatus to measure the speed of light in air versus water, based on a suggestion by <a href="/wiki/Fran%C3%A7ois_Arago" title="François Arago">François Arago</a>.<a href="#cite_note-Hughes2012-120">[107]</a> Today, using <a href="/wiki/Oscilloscopes" class="mw-redirect" title="Oscilloscopes">oscilloscopes</a> with time resolutions of less than one nanosecond, the speed of light can be directly measured by timing the delay of a light pulse from a laser or an LED reflected from a mirror. This method is less precise (with errors of the order of 1%) than other modern techniques, but it is sometimes used as a laboratory experiment in college physics classes.<a href="#cite_note-121">[108]</a> <div class="mw-heading mw-heading3"><h3 id="Electromagnetic_constants">Electromagnetic constants</h3></div> An option for deriving c that does not directly depend on a measurement of the propagation of electromagnetic waves is to use the relation between c and the <a href="/wiki/Vacuum_permittivity" title="Vacuum permittivity">vacuum permittivity</a> ε0 and <a href="/wiki/Vacuum_permeability" title="Vacuum permeability">vacuum permeability</a> μ0 established by Maxwell's theory: c2 = 1/(ε0μ0). The vacuum permittivity may be determined by measuring the <a href="/wiki/Capacitance" title="Capacitance">capacitance</a> and dimensions of a <a href="/wiki/Capacitor" title="Capacitor">capacitor</a>, whereas the value of the vacuum permeability was historically fixed at exactly 4π×10−7 H⋅m−1 through the definition of the <a href="/wiki/Ampere_(unit)" class="mw-redirect" title="Ampere (unit)">ampere</a>. <a href="/wiki/Edward_Bennett_Rosa" title="Edward Bennett Rosa">Rosa</a> and <a href="/wiki/Noah_Ernest_Dorsey" title="Noah Ernest Dorsey">Dorsey</a> used this method in 1907 to find a value of 299710±22 km/s. Their method depended upon having a standard unit of electrical resistance, the "international <a href="/wiki/Ohm" title="Ohm">ohm</a>", and so its accuracy was limited by how this standard was defined.<a href="#cite_note-Essen1948-122">[109]</a><a href="#cite_note-RosaDorsey-123">[110]</a> <div class="mw-heading mw-heading3"><h3 id="Cavity_resonance">Cavity resonance</h3></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Waves_in_Box.svg" class="mw-file-description"><img alt="A box with three waves in it; there are one and a half wavelength of the top wave, one of the middle one, and a half of the bottom one." src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Waves_in_Box.svg/220px-Waves_in_Box.svg.png" decoding="async" width="220" height="204" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Waves_in_Box.svg/330px-Waves_in_Box.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Waves_in_Box.svg/440px-Waves_in_Box.svg.png 2x" data-file-width="350" data-file-height="324" /></a><figcaption>Electromagnetic <a href="/wiki/Standing_waves" class="mw-redirect" title="Standing waves">standing waves</a> in a cavity</figcaption></figure> Another way to measure the speed of light is to independently measure the frequency f and wavelength λ of an electromagnetic wave in vacuum. The value of c can then be found by using the relation c = fλ. One option is to measure the resonance frequency of a <a href="/wiki/Cavity_resonator" class="mw-redirect" title="Cavity resonator">cavity resonator</a>. If the dimensions of the resonance cavity are also known, these can be used to determine the wavelength of the wave. In 1946, <a href="/wiki/Louis_Essen" title="Louis Essen">Louis Essen</a> and A.C. Gordon-Smith established the frequency for a variety of <a href="/wiki/Normal_mode" title="Normal mode">normal modes</a> of microwaves of a <a href="/wiki/Microwave_cavity" title="Microwave cavity">microwave cavity</a> of precisely known dimensions. The dimensions were established to an accuracy of about ±0.8 μm using gauges calibrated by interferometry.<a href="#cite_note-Essen1948-122">[109]</a> As the wavelength of the modes was known from the geometry of the cavity and from <a href="/wiki/Electromagnetic_theory" class="mw-redirect" title="Electromagnetic theory">electromagnetic theory</a>, knowledge of the associated frequencies enabled a calculation of the speed of light.<a href="#cite_note-Essen1948-122">[109]</a><a href="#cite_note-124">[111]</a> The Essen–Gordon-Smith result, 299792±9 km/s, was substantially more precise than those found by optical techniques.<a href="#cite_note-Essen1948-122">[109]</a> By 1950, repeated measurements by Essen established a result of 299792.5±3.0 km/s.<a href="#cite_note-Essen1950-125">[112]</a> A household demonstration of this technique is possible, using a <a href="/wiki/Microwave_oven" title="Microwave oven">microwave oven</a> and food such as marshmallows or margarine: if the turntable is removed so that the food does not move, it will cook the fastest at the <a href="/wiki/Antinode" class="mw-redirect" title="Antinode">antinodes</a> (the points at which the wave amplitude is the greatest), where it will begin to melt. The distance between two such spots is half the wavelength of the microwaves; by measuring this distance and multiplying the wavelength by the microwave frequency (usually displayed on the back of the oven, typically 2450 MHz), the value of c can be calculated, "often with less than 5% error".<a href="#cite_note-126">[113]</a><a href="#cite_note-127">[114]</a> <div class="mw-heading mw-heading3"><h3 id="Interferometry">Interferometry</h3></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Interferometer_sol.svg" class="mw-file-description"><img alt="Schematic of the working of a Michelson interferometer." src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Interferometer_sol.svg/220px-Interferometer_sol.svg.png" decoding="async" width="220" height="121" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Interferometer_sol.svg/330px-Interferometer_sol.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Interferometer_sol.svg/440px-Interferometer_sol.svg.png 2x" data-file-width="345" data-file-height="190" /></a><figcaption>An interferometric determination of length. Left: <a href="/wiki/Constructive_interference" class="mw-redirect" title="Constructive interference">constructive interference</a>; Right: <a href="/wiki/Destructive_interference" class="mw-redirect" title="Destructive interference">destructive interference</a>.</figcaption></figure> <a href="/wiki/Interferometry" title="Interferometry">Interferometry</a> is another method to find the wavelength of electromagnetic radiation for determining the speed of light.<a href="#cite_note-129">[Note 14]</a> A <a href="/wiki/Coherence_(physics)" title="Coherence (physics)">coherent</a> beam of light (e.g. from a <a href="/wiki/Laser" title="Laser">laser</a>), with a known frequency (f), is split to follow two paths and then recombined. By adjusting the path length while observing the <a href="/wiki/Interference_(wave_propagation)" class="mw-redirect" title="Interference (wave propagation)">interference pattern</a> and carefully measuring the change in path length, the wavelength of the light (λ) can be determined. The speed of light is then calculated using the equation c = λf. Before the advent of laser technology, coherent <a href="/wiki/Radiowave" class="mw-redirect" title="Radiowave">radio</a> sources were used for interferometry measurements of the speed of light.<a href="#cite_note-Froome1858-130">[116]</a> Interferometric determination of wavelength becomes less precise with wavelength and the experiments were thus limited in precision by the long wavelength (~4 mm (0.16 in)) of the radiowaves. The precision can be improved by using light with a shorter wavelength, but then it becomes difficult to directly measure the frequency of the light.<a href="#cite_note-NIST_pub-131">[117]</a> One way around this problem is to start with a low frequency signal of which the frequency can be precisely measured, and from this signal progressively synthesize higher frequency signals whose frequency can then be linked to the original signal. A laser can then be locked to the frequency, and its wavelength can be determined using interferometry.<a href="#cite_note-NIST_pub-131">[117]</a> This technique was due to a group at the National Bureau of Standards (which later became the <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">National Institute of Standards and Technology</a>). They used it in 1972 to measure the speed of light in vacuum with a <a href="/wiki/Measurement_uncertainty" title="Measurement uncertainty">fractional uncertainty</a> of 3.5×10−9.<a href="#cite_note-NIST_pub-131">[117]</a><a href="#cite_note-NIST_heterodyne-132">[118]</a> <div class="mw-heading mw-heading2"><h2 id="History">History</h2></div> Until the <a href="/wiki/Early_modern_period" title="Early modern period">early modern period</a>, it was not known whether light travelled instantaneously or at a very fast finite speed. The first extant recorded examination of this subject was in <a href="/wiki/Ancient_Greece" title="Ancient Greece">ancient Greece</a>. The ancient Greeks, Arabic scholars, and classical European scientists long debated this until Rømer provided the first calculation of the speed of light. Einstein's theory of special relativity postulates that the speed of light is constant regardless of one's frame of reference. Since then, scientists have provided increasingly accurate measurements. <table class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"> <caption>History of measurements of c (in m/s) </caption> <tbody><tr> <td><1638</td> <td><a href="/wiki/Galileo_Galilei" title="Galileo Galilei">Galileo</a>, covered lanterns</td> <td colspan="2">inconclusive<a href="#cite_note-2newsciences-133">[119]</a><a href="#cite_note-boyer-134">[120]</a><a href="#cite_note-foschi&leone-135">[121]</a>: 1252 <a href="#cite_note-136">[Note 15]</a> </td></tr> <tr> <td><1667</td> <td><a href="/wiki/Accademia_del_Cimento" title="Accademia del Cimento">Accademia del Cimento</a>, covered lanterns</td> <td colspan="2">inconclusive<a href="#cite_note-foschi&leone-135">[121]</a>: 1253 <a href="#cite_note-magalotti-137">[122]</a> </td></tr> <tr> <td>1675</td> <td><a href="/wiki/Ole_R%C3%B8mer" title="Ole Rømer">Rømer</a> and <a href="/wiki/Christiaan_Huygens" title="Christiaan Huygens">Huygens</a>, moons of Jupiter</td> <td>220000000<a href="#cite_note-roemer-106">[95]</a><a href="#cite_note-Huygens_1690_8–9-138">[123]</a></td> <td>−27% </td></tr> <tr> <td>1729</td> <td><a href="/wiki/James_Bradley" title="James Bradley">James Bradley</a>, aberration of light</td> <td>301000000<a href="#cite_note-How-118">[105]</a></td> <td>+0.40% </td></tr> <tr> <td>1849</td> <td><a href="/wiki/Hippolyte_Fizeau" title="Hippolyte Fizeau">Hippolyte Fizeau</a>, toothed wheel</td> <td>315000000<a href="#cite_note-How-118">[105]</a></td> <td>+5.1% </td></tr> <tr> <td>1862</td> <td><a href="/wiki/L%C3%A9on_Foucault" title="Léon Foucault">Léon Foucault</a>, rotating mirror</td> <td>298000000±500000<a href="#cite_note-How-118">[105]</a></td> <td>−0.60% </td></tr> <tr> <td>1875</td> <td>Werner Siemens</td> <td>260 000 000<a href="#cite_note-139">[124]</a></td> <td> </td></tr> <tr> <td>1893</td> <td><a href="/wiki/Heinrich_Hertz" title="Heinrich Hertz">Heinrich Hertz</a></td> <td>200 000 000<a href="#cite_note-140">[125]</a></td> <td> </td></tr> <tr> <td>1907</td> <td>Rosa and Dorsey, <abbr title="electromagnetic">EM</abbr> constants</td> <td>299710000±30000<a href="#cite_note-Essen1948-122">[109]</a><a href="#cite_note-RosaDorsey-123">[110]</a></td> <td>−280 <a href="/wiki/Parts-per_notation" title="Parts-per notation">ppm</a> </td></tr> <tr> <td>1926</td> <td><a href="/wiki/Albert_A._Michelson" title="Albert A. Michelson">Albert A. Michelson</a>, rotating mirror</td> <td>299796000±4000<a href="#cite_note-141">[126]</a></td> <td>+12 ppm </td></tr> <tr> <td>1950</td> <td>Essen and Gordon-Smith, cavity resonator</td> <td>299792500±3000<a href="#cite_note-Essen1950-125">[112]</a></td> <td>+0.14 ppm </td></tr> <tr> <td>1958</td> <td>K. D. Froome, radio interferometry</td> <td>299792500±100<a href="#cite_note-Froome1858-130">[116]</a></td> <td>+0.14 ppm </td></tr> <tr> <td>1972</td> <td>Evenson et al., laser interferometry</td> <td>299792456.2±1.1<a href="#cite_note-NIST_heterodyne-132">[118]</a></td> <td>−0.006 ppm </td></tr> <tr> <td>1983</td> <td>17th CGPM, definition of the metre</td> <td colspan="2">299792458 (exact)<a href="#cite_note-Resolution_1-104">[93]</a> </td></tr></tbody></table> <div class="mw-heading mw-heading3"><h3 id="Early_history">Early history</h3></div> <a href="/wiki/Empedocles" title="Empedocles">Empedocles</a> (c. 490–430 BCE) was the first to propose a theory of light<a href="#cite_note-142">[127]</a> and claimed that light has a finite speed.<a href="#cite_note-143">[128]</a> He maintained that light was something in motion, and therefore must take some time to travel. <a href="/wiki/Aristotle" title="Aristotle">Aristotle</a> argued, to the contrary, that "light is due to the presence of something, but it is not a movement".<a href="#cite_note-Statistics-144">[129]</a> <a href="/wiki/Euclid" title="Euclid">Euclid</a> and <a href="/wiki/Ptolemy" title="Ptolemy">Ptolemy</a> advanced Empedocles' <a href="/wiki/Emission_theory_(vision)" title="Emission theory (vision)">emission theory</a> of vision, where light is emitted from the eye, thus enabling sight. Based on that theory, <a href="/wiki/Heron_of_Alexandria" class="mw-redirect" title="Heron of Alexandria">Heron of Alexandria</a> argued that the speed of light must be <a href="/wiki/Infinity" title="Infinity">infinite</a> because distant objects such as stars appear immediately upon opening the eyes.<a href="#cite_note-145">[130]</a> <a href="/wiki/Early_Islamic_philosophy" title="Early Islamic philosophy">Early Islamic philosophers</a> initially agreed with the <a href="/wiki/Aristotelian_physics" title="Aristotelian physics">Aristotelian view</a> that light had no speed of travel. In 1021, <a href="/wiki/Alhazen" class="mw-redirect" title="Alhazen">Alhazen</a> (Ibn al-Haytham) published the <a href="/wiki/Book_of_Optics" title="Book of Optics">Book of Optics</a>, in which he presented a series of arguments dismissing the emission theory of <a href="/wiki/Visual_perception" title="Visual perception">vision</a> in favour of the now accepted intromission theory, in which light moves from an object into the eye.<a href="#cite_note-146">[131]</a> This led Alhazen to propose that light must have a finite speed,<a href="#cite_note-Statistics-144">[129]</a><a href="#cite_note-Hamarneh-147">[132]</a><a href="#cite_note-Lester-148">[133]</a> and that the speed of light is variable, decreasing in denser bodies.<a href="#cite_note-Lester-148">[133]</a><a href="#cite_note-149">[134]</a> He argued that light is substantial matter, the propagation of which requires time, even if this is hidden from the senses.<a href="#cite_note-150">[135]</a> Also in the 11th century, <a href="/wiki/Al-Biruni" title="Al-Biruni">Abū Rayhān al-Bīrūnī</a> agreed that light has a finite speed, and observed that the speed of light is much faster than the speed of sound.<a href="#cite_note-151">[136]</a> In the 13th century, <a href="/wiki/Roger_Bacon" title="Roger Bacon">Roger Bacon</a> argued that the speed of light in air was not infinite, using philosophical arguments backed by the writing of Alhazen and Aristotle.<a href="#cite_note-Lindberg-152">[137]</a><a href="#cite_note-153">[138]</a> In the 1270s, <a href="/wiki/Witelo" class="mw-redirect" title="Witelo">Witelo</a> considered the possibility of light travelling at infinite speed in vacuum, but slowing down in denser bodies.<a href="#cite_note-Marshall-154">[139]</a> In the early 17th century, <a href="/wiki/Johannes_Kepler" title="Johannes Kepler">Johannes Kepler</a> believed that the speed of light was infinite since empty space presents no obstacle to it. <a href="/wiki/Ren%C3%A9_Descartes" title="René Descartes">René Descartes</a> argued that if the speed of light were to be finite, the Sun, Earth, and Moon would be noticeably out of alignment during a <a href="/wiki/Lunar_eclipse" title="Lunar eclipse">lunar eclipse</a>. Although this argument fails when aberration of light is taken into account, the latter was not recognized until the following century.<a href="#cite_note-155">[140]</a> Since such misalignment had not been observed, Descartes concluded the speed of light was infinite. Descartes speculated that if the speed of light were found to be finite, his whole system of philosophy might be demolished.<a href="#cite_note-Statistics-144">[129]</a> Despite this, in his derivation of <a href="/wiki/Snell%27s_law" title="Snell's law">Snell's law</a>, Descartes assumed that some kind of motion associated with light was faster in denser media.<a href="#cite_note-156">[141]</a><a href="#cite_note-157">[142]</a> <a href="/wiki/Pierre_de_Fermat" title="Pierre de Fermat">Pierre de Fermat</a> derived Snell's law using the opposing assumption, the denser the medium the slower light travelled. Fermat also argued in support of a finite speed of light.<a href="#cite_note-158">[143]</a> <div class="mw-heading mw-heading3"><h3 id="First_measurement_attempts">First measurement attempts</h3></div> In 1629, <a href="/wiki/Isaac_Beeckman" title="Isaac Beeckman">Isaac Beeckman</a> proposed an experiment in which a person observes the flash of a cannon reflecting off a mirror about one mile (1.6 km) away. In 1638, <a href="/wiki/Galileo_Galilei" title="Galileo Galilei">Galileo Galilei</a> proposed an experiment, with an apparent claim to having performed it some years earlier, to measure the speed of light by observing the delay between uncovering a lantern and its perception some distance away. He was unable to distinguish whether light travel was instantaneous or not, but concluded that if it were not, it must nevertheless be extraordinarily rapid.<a href="#cite_note-2newsciences-133">[119]</a><a href="#cite_note-boyer-134">[120]</a> In 1667, the <a href="/wiki/Accademia_del_Cimento" title="Accademia del Cimento">Accademia del Cimento</a> of Florence reported that it had performed Galileo's experiment, with the lanterns separated by about one mile, but no delay was observed.<a href="#cite_note-159">[144]</a> The actual delay in this experiment would have been about 11 <a href="/wiki/Microsecond" title="Microsecond">microseconds</a>. <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Illustration_from_1676_article_on_Ole_R%C3%B8mer%27s_measurement_of_the_speed_of_light.png" class="mw-file-description"><img alt="A diagram of a planet's orbit around the Sun and of a moon's orbit around another planet. The shadow of the latter planet is shaded." src="//upload.wikimedia.org/wikipedia/commons/thumb/7/79/Illustration_from_1676_article_on_Ole_R%C3%B8mer%27s_measurement_of_the_speed_of_light.png/180px-Illustration_from_1676_article_on_Ole_R%C3%B8mer%27s_measurement_of_the_speed_of_light.png" decoding="async" width="180" height="334" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/79/Illustration_from_1676_article_on_Ole_R%C3%B8mer%27s_measurement_of_the_speed_of_light.png/270px-Illustration_from_1676_article_on_Ole_R%C3%B8mer%27s_measurement_of_the_speed_of_light.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/79/Illustration_from_1676_article_on_Ole_R%C3%B8mer%27s_measurement_of_the_speed_of_light.png/360px-Illustration_from_1676_article_on_Ole_R%C3%B8mer%27s_measurement_of_the_speed_of_light.png 2x" data-file-width="395" data-file-height="733" /></a><figcaption>Rømer's observations of the occultations of Io from Earth</figcaption></figure> <a href="/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light" title="Rømer's determination of the speed of light">The first quantitative estimate of the speed of light</a> was made in 1676 by Ole Rømer.<a href="#cite_note-cohen-105">[94]</a><a href="#cite_note-roemer-106">[95]</a> From the observation that the periods of Jupiter's innermost moon <a href="/wiki/Io_(moon)" title="Io (moon)">Io</a> appeared to be shorter when the Earth was approaching Jupiter than when receding from it, he concluded that light travels at a finite speed, and estimated that it takes light 22 minutes to cross the diameter of Earth's orbit. <a href="/wiki/Christiaan_Huygens" title="Christiaan Huygens">Christiaan Huygens</a> combined this estimate with an estimate for the diameter of the Earth's orbit to obtain an estimate of speed of light of 220000 km/s, which is 27% lower than the actual value.<a href="#cite_note-Huygens_1690_8–9-138">[123]</a> In his 1704 book <a href="/wiki/Opticks" title="Opticks">Opticks</a>, <a href="/wiki/Isaac_Newton" title="Isaac Newton">Isaac Newton</a> reported Rømer's calculations of the finite speed of light and gave a value of "seven or eight minutes" for the time taken for light to travel from the Sun to the Earth (the modern value is 8 minutes 19 seconds).<a href="#cite_note-160">[145]</a> Newton queried whether Rømer's eclipse shadows were coloured. Hearing that they were not, he concluded the different colours travelled at the same speed. In 1729, <a href="/wiki/James_Bradley" title="James Bradley">James Bradley</a> discovered <a href="/wiki/Aberration_of_light" class="mw-redirect" title="Aberration of light">stellar aberration</a>.<a href="#cite_note-Bradley1729-107">[96]</a> From this effect he determined that light must travel 10,210 times faster than the Earth in its orbit (the modern figure is 10,066 times faster) or, equivalently, that it would take light 8 minutes 12 seconds to travel from the Sun to the Earth.<a href="#cite_note-Bradley1729-107">[96]</a> <div class="mw-heading mw-heading3"><h3 id="Connections_with_electromagnetism">Connections with electromagnetism</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/History_of_electromagnetic_theory" title="History of electromagnetic theory">History of electromagnetic theory</a> and <a href="/wiki/History_of_special_relativity" title="History of special relativity">History of special relativity</a></div> In the 19th century <a href="/wiki/Hippolyte_Fizeau" title="Hippolyte Fizeau">Hippolyte Fizeau</a> developed a method to determine the speed of light based on time-of-flight measurements on Earth and reported a value of 315000 km/s.<a href="#cite_note-guarnieri_7-1-161">[146]</a> His method was improved upon by <a href="/wiki/L%C3%A9on_Foucault" title="Léon Foucault">Léon Foucault</a> who obtained a value of 298000 km/s in 1862.<a href="#cite_note-How-118">[105]</a> In the year 1856, <a href="/wiki/Wilhelm_Eduard_Weber" title="Wilhelm Eduard Weber">Wilhelm Eduard Weber</a> and <a href="/wiki/Rudolf_Kohlrausch" title="Rudolf Kohlrausch">Rudolf Kohlrausch</a> measured the ratio of the electromagnetic and electrostatic units of charge, 1/√ε0μ0, by discharging a <a href="/wiki/Leyden_jar" title="Leyden jar">Leyden jar</a>, and found that its numerical value was very close to the speed of light as measured directly by Fizeau. The following year <a href="/wiki/Gustav_Kirchhoff" title="Gustav Kirchhoff">Gustav Kirchhoff</a> calculated that an electric signal in a <a href="/wiki/Electrical_resistance" class="mw-redirect" title="Electrical resistance">resistanceless</a> wire travels along the wire at this speed.<a href="#cite_note-162">[147]</a> In the early 1860s, Maxwell showed that, according to the theory of electromagnetism he was working on, electromagnetic waves propagate in empty space<a href="#cite_note-163">[148]</a> at a speed equal to the above Weber/Kohlrausch ratio, and drawing attention to the numerical proximity of this value to the speed of light as measured by Fizeau, he proposed that light is in fact an electromagnetic wave.<a href="#cite_note-maxwellbio-164">[149]</a> Maxwell backed up his claim with his own experiment published in the 1868 Philosophical Transactions which determined the ratio of the electrostatic and electromagnetic units of electricity.<a href="#cite_note-165">[150]</a> <div class="mw-heading mw-heading3"><h3 id=""Luminiferous_aether"">"Luminiferous aether"</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Luminiferous_aether" title="Luminiferous aether">Luminiferous aether</a></div> The wave properties of light were well known since <a href="/wiki/Thomas_Young_(scientist)" title="Thomas Young (scientist)">Thomas Young</a>. In the 19th century, physicists believed light was propagating in a medium called aether (or ether). But for electric force, it looks more like the gravitational force in Newton's law. A transmitting medium was not required. After Maxwell theory unified light and electric and magnetic waves, it was favored that both light and electric magnetic waves propagate in the same aether medium (or called the <a href="/wiki/Luminiferous_aether" title="Luminiferous aether">luminiferous aether</a>).<a href="#cite_note-166">[151]</a> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Einstein_en_Lorentz.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c6/Einstein_en_Lorentz.jpg/170px-Einstein_en_Lorentz.jpg" decoding="async" width="170" height="224" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c6/Einstein_en_Lorentz.jpg/255px-Einstein_en_Lorentz.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c6/Einstein_en_Lorentz.jpg/340px-Einstein_en_Lorentz.jpg 2x" data-file-width="1712" data-file-height="2256" /></a><figcaption>Hendrik Lorentz (right) with Albert Einstein (1921)</figcaption></figure> It was thought at the time that empty space was filled with a background medium called the luminiferous aether in which the electromagnetic field existed. Some physicists thought that this aether acted as a <a href="/wiki/Preferred_frame" title="Preferred frame">preferred frame</a> of reference for the propagation of light and therefore it should be possible to measure the motion of the Earth with respect to this medium, by measuring the <a href="/wiki/Isotropy" title="Isotropy">isotropy</a> of the speed of light. Beginning in the 1880s several experiments were performed to try to detect this motion, the most famous of which is <a href="/wiki/Michelson%E2%80%93Morley_experiment" title="Michelson–Morley experiment">the experiment</a> performed by <a href="/wiki/Albert_A._Michelson" title="Albert A. Michelson">Albert A. Michelson</a> and <a href="/wiki/Edward_W._Morley" title="Edward W. Morley">Edward W. Morley</a> in 1887.<a href="#cite_note-167">[152]</a><a href="#cite_note-168">[153]</a> The detected motion was found to always be nil (within observational error). Modern experiments indicate that the two-way speed of light is <a href="/wiki/Isotropic" class="mw-redirect" title="Isotropic">isotropic</a> (the same in every direction) to within 6 nanometres per second.<a href="#cite_note-169">[154]</a> Because of this experiment <a href="/wiki/Hendrik_Lorentz" title="Hendrik Lorentz">Hendrik Lorentz</a> proposed that the motion of the apparatus through the aether may cause the apparatus to <a href="/wiki/Lorentz_contraction" class="mw-redirect" title="Lorentz contraction">contract</a> along its length in the direction of motion, and he further assumed that the time variable for moving systems must also be changed accordingly ("local time"), which led to the formulation of the <a href="/wiki/Lorentz_transformation" title="Lorentz transformation">Lorentz transformation</a>. Based on <a href="/wiki/Lorentz_ether_theory" title="Lorentz ether theory">Lorentz's aether theory</a>, <a href="/wiki/Henri_Poincar%C3%A9" title="Henri Poincaré">Henri Poincaré</a> (1900) showed that this local time (to first order in v/c) is indicated by clocks moving in the aether, which are synchronized under the assumption of constant light speed. In 1904, he speculated that the speed of light could be a limiting velocity in dynamics, provided that the assumptions of Lorentz's theory are all confirmed. In 1905, Poincaré brought Lorentz's aether theory into full observational agreement with the <a href="/wiki/Principle_of_relativity" title="Principle of relativity">principle of relativity</a>.<a href="#cite_note-170">[155]</a><a href="#cite_note-171">[156]</a> <div class="mw-heading mw-heading3"><h3 id="Special_relativity">Special relativity</h3></div> In 1905 Einstein postulated from the outset that the speed of light in vacuum, measured by a non-accelerating observer, is independent of the motion of the source or observer. Using this and the principle of relativity as a basis he derived the <a href="/wiki/Special_theory_of_relativity" class="mw-redirect" title="Special theory of relativity">special theory of relativity</a>, in which the speed of light in vacuum c featured as a fundamental constant, also appearing in contexts unrelated to light. This made the concept of the stationary aether (to which Lorentz and Poincaré still adhered) useless and revolutionized the concepts of space and time.<a href="#cite_note-172">[157]</a><a href="#cite_note-173">[158]</a> <div class="mw-heading mw-heading3"><h3 id="Increased_accuracy_of_c_and_redefinition_of_the_metre_and_second">Increased accuracy of c and redefinition of the metre and second</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/History_of_the_metre" title="History of the metre">History of the metre</a></div> In the second half of the 20th century, much progress was made in increasing the accuracy of measurements of the speed of light, first by cavity resonance techniques and later by laser interferometer techniques. These were aided by new, more precise, definitions of the metre and second. In 1950, <a href="/wiki/Louis_Essen" title="Louis Essen">Louis Essen</a> determined the speed as 299792.5±3.0 km/s, using cavity resonance.<a href="#cite_note-Essen1950-125">[112]</a> This value was adopted by the 12th General Assembly of the Radio-Scientific Union in 1957. In 1960, the <a href="/wiki/History_of_the_metre#Krypton_standard" title="History of the metre">metre was redefined</a> in terms of the wavelength of a particular spectral line of <a href="/wiki/Krypton-86" class="mw-redirect" title="Krypton-86">krypton-86</a>, and, in 1967, the second was redefined in terms of the hyperfine transition frequency of the ground state of <a href="/wiki/Caesium-133" class="mw-redirect" title="Caesium-133">caesium-133</a>.<a href="#cite_note-13thCGPMr1-174">[159]</a> In 1972, using the laser interferometer method and the new definitions, a group at the US <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">National Bureau of Standards</a> in <a href="/wiki/Boulder,_Colorado" title="Boulder, Colorado">Boulder, Colorado</a> determined the speed of light in vacuum to be c = 299792456.2±1.1 m/s. This was 100 times less uncertain than the previously accepted value. The remaining uncertainty was mainly related to the definition of the metre.<a href="#cite_note-177">[Note 16]</a><a href="#cite_note-NIST_heterodyne-132">[118]</a> As similar experiments found comparable results for c, the 15th <a href="/wiki/General_Conference_on_Weights_and_Measures" title="General Conference on Weights and Measures">General Conference on Weights and Measures</a> in 1975 recommended using the value 299792458 m/s for the speed of light.<a href="#cite_note-15thCGPM-178">[162]</a> <div class="mw-heading mw-heading3"><h3 id="Defined_as_an_explicit_constant">Defined as an explicit constant</h3></div> In 1983 the 17th meeting of the General Conference on Weights and Measures (CGPM) found that wavelengths from frequency measurements and a given value for the speed of light are more <a href="/wiki/Reproducibility" title="Reproducibility">reproducible</a> than the previous standard. They kept the 1967 definition of second, so the <a href="/wiki/Caesium" title="Caesium">caesium</a> <a href="/wiki/Hyperfine_structure#Use_in_defining_the_SI_second_and_meter" title="Hyperfine structure">hyperfine frequency</a> would now determine both the second and the metre. To do this, they redefined the metre as "the length of the path traveled by light in vacuum during a time interval of 1/299792458 of a second".<a href="#cite_note-Resolution_1-104">[93]</a> As a result of this definition, the value of the speed of light in vacuum is exactly 299792458 m/s<a href="#cite_note-Wheeler-179">[163]</a><a href="#cite_note-timeline-180">[164]</a> and has become a defined constant in the SI system of units.<a href="#cite_note-fixes-17">[14]</a> Improved experimental techniques that, prior to 1983, would have measured the speed of light no longer affect the known value of the speed of light in SI units, but instead allow a more precise realization of the metre by more accurately measuring the wavelength of krypton-86 and other light sources.<a href="#cite_note-Adams-181">[165]</a><a href="#cite_note-W_Rindler-182">[166]</a> In 2011, the CGPM stated its intention to redefine all seven SI base units using what it calls "the explicit-constant formulation", where each "unit is defined indirectly by specifying explicitly an exact value for a well-recognized fundamental constant", as was done for the speed of light. It proposed a new, but completely equivalent, wording of the metre's definition: "The metre, symbol m, is the unit of length; its magnitude is set by fixing the numerical value of the speed of light in vacuum to be equal to exactly 299792458 when it is expressed in the SI unit m s−1."<a href="#cite_note-183">[167]</a> This was one of the changes that was incorporated in the <a href="/wiki/2019_revision_of_the_SI" title="2019 revision of the SI">2019 revision of the SI</a>, also termed the New SI.<a href="#cite_note-184">[168]</a> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div> <style data-mw-deduplicate="TemplateStyles:r1259569809">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output .portalborder{border:1px solid var(--border-color-base,#a2a9b1);padding:0.1em;background:var(--background-color-neutral-subtle,#f8f9fa)}.mw-parser-output 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ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 20em;"> <ul><li><a href="/wiki/Light-second" title="Light-second">Light-second</a></li> <li><a href="/wiki/Speed_of_electricity" title="Speed of electricity">Speed of electricity</a></li> <li><a href="/wiki/Speed_of_gravity" title="Speed of gravity">Speed of gravity</a></li> <li><a href="/wiki/Speed_of_sound" title="Speed of sound">Speed of sound</a></li> <li><a href="/wiki/Velocity_factor" title="Velocity factor">Velocity factor</a></li> <li><a href="/wiki/Warp_drive" title="Warp drive">Warp factor</a> (fictional)</li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-2"><a href="#cite_ref-2">^</a> Exact value: (299792458 × 86400 / 149597870700) AU/day. </li> <li id="cite_note-3"><a href="#cite_ref-3">^</a> Exact value: (999992651 π / 10246429500) pc/y. </li> <li id="cite_note-6"><a href="#cite_ref-6">^</a> It is exact because, by a 1983 international agreement, a <a href="/wiki/Metre#Speed_of_light_definition" title="Metre">metre</a> is defined as the length of the path travelled by <a href="/wiki/Light" title="Light">light</a> in vacuum during a time interval of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027">1⁄299792458 <a href="/wiki/Second" title="Second">second</a>. This particular value was chosen to provide a more accurate definition of the metre that still agreed as much as possible with the definition used before. See, for example, the <a href="/wiki/NIST" class="mw-redirect" title="NIST">NIST</a> website<a href="#cite_note-nist-definitions-4">[2]</a> or the explanation by <a href="/wiki/Roger_Penrose" title="Roger Penrose">Penrose</a>.<a href="#cite_note-penrose-5">[3]</a> The second is, in turn, defined to be the length of time occupied by 9192631770 cycles of the radiation emitted by a <a href="/wiki/Caesium" title="Caesium">caesium</a>-133 <a href="/wiki/Atom" title="Atom">atom</a> in a transition between two specified <a href="/wiki/Energy_level" title="Energy level">energy states</a>.<a href="#cite_note-nist-definitions-4">[2]</a> </li> <li id="cite_note-imperial-18"><a href="#cite_ref-imperial_18-0">^</a> The speed of light in imperial is exactly <dl><dd>186282 miles, 698 yd, 2 ft, and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035">⁠5+21/127⁠ inches per second.</dd></dl> </li> <li id="cite_note-nanosecond-19"><a href="#cite_ref-nanosecond_19-0">^</a> The exact value is <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035">⁠149896229/152400000⁠ <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035">⁠ft/ns⁠ ≈ 0.98 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1214402035">⁠ft/ns⁠. </li> <li id="cite_note-24"><a href="#cite_ref-24">^</a> However, the <a href="/wiki/Frequency" title="Frequency">frequency</a> of light can depend on the motion of the source relative to the observer, due to the <a href="/wiki/Doppler_effect" title="Doppler effect">Doppler effect</a>. </li> <li id="cite_note-26"><a href="#cite_ref-26">^</a> See <a href="/wiki/Michelson%E2%80%93Morley_experiment" title="Michelson–Morley experiment">Michelson–Morley experiment</a> and <a href="/wiki/Kennedy%E2%80%93Thorndike_experiment" title="Kennedy–Thorndike experiment">Kennedy–Thorndike experiment</a>, for example. </li> <li id="cite_note-33"><a href="#cite_ref-33">^</a> Because <a href="/wiki/Neutrino" title="Neutrino">neutrinos</a> have a small but non-zero mass, they travel through empty space <a href="/wiki/Measurements_of_neutrino_speed" title="Measurements of neutrino speed">very slightly more slowly than light</a>. However, because they pass through matter much more easily than light does, there are in theory occasions when the neutrino signal from an astronomical event might reach Earth before an optical signal can, like <a href="/wiki/Supernova" title="Supernova">supernovae</a>.<a href="#cite_note-32">[25]</a> </li> <li id="cite_note-37"><a href="#cite_ref-37">^</a> Whereas moving objects are measured to be shorter along the line of relative motion, they are also seen as being rotated. This effect, known as <a href="/wiki/Terrell_rotation" title="Terrell rotation">Terrell rotation</a>, is due to the different times that light from different parts of the object takes to reach the observer.<a href="#cite_note-35">[27]</a><a href="#cite_note-36">[28]</a> </li> <li id="cite_note-52"><a href="#cite_ref-52">^</a> It has been speculated that the <a href="/wiki/Scharnhorst_effect" title="Scharnhorst effect">Scharnhorst effect</a> does allow signals to travel slightly faster than c, but the validity of those calculations has been questioned,<a href="#cite_note-50">[41]</a> and it appears the special conditions in which this effect might occur would prevent one from using it to violate causality.<a href="#cite_note-51">[42]</a> </li> <li id="cite_note-89"><a href="#cite_ref-89">^</a> A typical value for the refractive index of optical fibre is between 1.518 and 1.538.<a href="#cite_note-Midwinter-88">[78]</a> </li> <li id="cite_note-112"><a href="#cite_ref-112">^</a> The astronomical unit was defined as the radius of an unperturbed circular Newtonian orbit about the Sun of a particle having infinitesimal mass, moving with an <a href="/wiki/Angular_frequency" title="Angular frequency">angular frequency</a> of 0.01720209895 <a href="/wiki/Radian" title="Radian">radians</a> (approximately <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027">1⁄365.256898 of a revolution) per day.<a href="#cite_note-111">[100]</a> </li> <li id="cite_note-117"><a href="#cite_ref-117">^</a> Nevertheless, at this degree of precision, the effects of <a href="/wiki/General_relativity" title="General relativity">general relativity</a> must be taken into consideration when interpreting the length. The metre is considered to be a unit of <a href="/wiki/Proper_length" title="Proper length">proper length</a>, whereas the AU is usually used as a unit of observed length in a given frame of reference. The values cited here follow the latter convention, and are <a href="/wiki/Barycentric_Dynamical_Time" title="Barycentric Dynamical Time">TDB</a>-compatible.<a href="#cite_note-IAU-115">[103]</a> </li> <li id="cite_note-129"><a href="#cite_ref-129">^</a> A detailed discussion of the interferometer and its use for determining the speed of light can be found in Vaughan (1989).<a href="#cite_note-Vaughan-128">[115]</a> </li> <li id="cite_note-136"><a href="#cite_ref-136">^</a> According to Galileo, the lanterns he used were "at a short distance, less than a mile". Assuming the distance was not too much shorter than a mile, and that "about a thirtieth of a second is the minimum time interval distinguishable by the unaided eye", Boyer notes that Galileo's experiment could at best be said to have established a lower limit of about 60 miles per second for the velocity of light.<a href="#cite_note-boyer-134">[120]</a> </li> <li id="cite_note-177"><a href="#cite_ref-177">^</a> Between 1960 and 1983 the metre was defined as "the length equal to 1650763.73 wavelengths in vacuum of the radiation corresponding to the transition between the levels 2p10 and 5d5 of the krypton-86 atom".<a href="#cite_note-11thCGPM-175">[160]</a> It was discovered in the 1970s that this spectral line was not symmetric, which put a limit on the precision with which the definition could be realized in interferometry experiments.<a href="#cite_note-176">[161]</a> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><a href="#cite_ref-1">^</a> <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFLarsonHostetler2007" class="citation book cs1">Larson, Ron; Hostetler, Robert P. (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=qe-YvKoeiasC&pg=PA179">Elementary and Intermediate Algebra: A Combined Course, Student Support Edition</a> (4th illustrated ed.). Cengage Learning. p. 197. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-618-75354-3" title="Special:BookSources/978-0-618-75354-3"><bdi>978-0-618-75354-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Elementary+and+Intermediate+Algebra%3A+A+Combined+Course%2C+Student+Support+Edition&rft.pages=197&rft.edition=4th+illustrated&rft.pub=Cengage+Learning&rft.date=2007&rft.isbn=978-0-618-75354-3&rft.aulast=Larson&rft.aufirst=Ron&rft.au=Hostetler%2C+Robert+P.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dqe-YvKoeiasC%26pg%3DPA179&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-nist-definitions-4">^ <a href="#cite_ref-nist-definitions_4-0">a</a> <a href="#cite_ref-nist-definitions_4-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://physics.nist.gov/cuu/Units/current.html">"Definitions of the SI base units"</a>. physics.nist.gov. 29 May 2019. Retrieved 8 February 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=physics.nist.gov&rft.atitle=Definitions+of+the+SI+base+units&rft.date=2019-05-29&rft_id=https%3A%2F%2Fphysics.nist.gov%2Fcuu%2FUnits%2Fcurrent.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-penrose-5"><a href="#cite_ref-penrose_5-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPenrose2004" class="citation book cs1"><a href="/wiki/Roger_Penrose" title="Roger Penrose">Penrose, R</a> (2004). <a href="/wiki/The_Road_to_Reality:_A_Complete_Guide_to_the_Laws_of_the_Universe" class="mw-redirect" title="The Road to Reality: A Complete Guide to the Laws of the Universe">The Road to Reality: A Complete Guide to the Laws of the Universe</a>. Vintage Books. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/roadtoreality00penr_319/page/n438">410</a>–411. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-679-77631-4" title="Special:BookSources/978-0-679-77631-4"><bdi>978-0-679-77631-4</bdi></a>. <q>... the most accurate standard for the metre is conveniently defined so that there are exactly 299792458 of them to the distance travelled by light in a standard second, giving a value for the metre that very accurately matches the now inadequately precise <a href="/wiki/History_of_the_metre#International_prototype_metre" title="History of the metre">standard metre rule</a> in Paris.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Road+to+Reality%3A+A+Complete+Guide+to+the+Laws+of+the+Universe&rft.pages=410-411&rft.pub=Vintage+Books&rft.date=2004&rft.isbn=978-0-679-77631-4&rft.aulast=Penrose&rft.aufirst=R&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-7"><a href="#cite_ref-7">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMoses_Fayngold2008" class="citation book cs1">Moses Fayngold (2008). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Q3egk8Ds6ogC">Special Relativity and How it Works</a> (illustrated ed.). John Wiley & Sons. p. 497. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-527-40607-4" title="Special:BookSources/978-3-527-40607-4"><bdi>978-3-527-40607-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Special+Relativity+and+How+it+Works&rft.pages=497&rft.edition=illustrated&rft.pub=John+Wiley+%26+Sons&rft.date=2008&rft.isbn=978-3-527-40607-4&rft.au=Moses+Fayngold&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DQ3egk8Ds6ogC&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Q3egk8Ds6ogC&pg=PA497">Extract of page 497</a>. </li> <li id="cite_note-8"><a href="#cite_ref-8">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAlbert_Shadowitz1988" class="citation book cs1">Albert Shadowitz (1988). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=1axfJqUT6R0C">Special Relativity</a> (revised ed.). Courier Corporation. p. 79. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-486-65743-1" title="Special:BookSources/978-0-486-65743-1"><bdi>978-0-486-65743-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Special+Relativity&rft.pages=79&rft.edition=revised&rft.pub=Courier+Corporation&rft.date=1988&rft.isbn=978-0-486-65743-1&rft.au=Albert+Shadowitz&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D1axfJqUT6R0C&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://books.google.com/books?id=1axfJqUT6R0C&pg=PA79">Extract of page 79</a>. </li> <li id="cite_note-9"><a href="#cite_ref-9">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPeresTerno2004" class="citation journal cs1"><a href="/wiki/Asher_Peres" title="Asher Peres">Peres, Asher</a>; Terno, Daniel R. (6 January 2004). <a rel="nofollow" class="external text" href="https://link.aps.org/doi/10.1103/RevModPhys.76.93">"Quantum information and relativity theory"</a>. Reviews of Modern Physics. 76 (1): 93–123. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/quant-ph/0212023">quant-ph/0212023</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004RvMP...76...93P">2004RvMP...76...93P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FRevModPhys.76.93">10.1103/RevModPhys.76.93</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0034-6861">0034-6861</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:7481797">7481797</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Reviews+of+Modern+Physics&rft.atitle=Quantum+information+and+relativity+theory&rft.volume=76&rft.issue=1&rft.pages=93-123&rft.date=2004-01-06&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A7481797%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2004RvMP...76...93P&rft_id=info%3Aarxiv%2Fquant-ph%2F0212023&rft.issn=0034-6861&rft_id=info%3Adoi%2F10.1103%2FRevModPhys.76.93&rft.aulast=Peres&rft.aufirst=Asher&rft.au=Terno%2C+Daniel+R.&rft_id=https%3A%2F%2Flink.aps.org%2Fdoi%2F10.1103%2FRevModPhys.76.93&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-10"><a href="#cite_ref-10">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGibbs1997" class="citation web cs1">Gibbs, Philip (1997). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20150821181850/http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/measure_c.html">"How is the speed of light measured?"</a>. The Physics and Relativity FAQ. Archived from <a rel="nofollow" class="external text" href="http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/measure_c.html">the original</a> on 21 August 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Physics+and+Relativity+FAQ&rft.atitle=How+is+the+speed+of+light+measured%3F&rft.date=1997&rft.aulast=Gibbs&rft.aufirst=Philip&rft_id=http%3A%2F%2Fmath.ucr.edu%2Fhome%2Fbaez%2Fphysics%2FRelativity%2FSpeedOfLight%2Fmeasure_c.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-stachel-11">^ <a href="#cite_ref-stachel_11-0">a</a> <a href="#cite_ref-stachel_11-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStachel2002" class="citation book cs1">Stachel, J. J. (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=OAsQ_hFjhrAC&pg=PA226">Einstein from "B" to "Z" – Volume 9 of Einstein studies</a>. Springer. p. 226. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8176-4143-6" title="Special:BookSources/978-0-8176-4143-6"><bdi>978-0-8176-4143-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Einstein+from+%22B%22+to+%22Z%22+%E2%80%93+Volume+9+of+Einstein+studies&rft.pages=226&rft.pub=Springer&rft.date=2002&rft.isbn=978-0-8176-4143-6&rft.aulast=Stachel&rft.aufirst=J.+J.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DOAsQ_hFjhrAC%26pg%3DPA226&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-12"><a href="#cite_ref-12">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFeigenbaumMermin1988" class="citation journal cs1"><a href="/wiki/Mitchell_Feigenbaum" title="Mitchell Feigenbaum">Feigenbaum, Mitchell J.</a>; <a href="/wiki/N._David_Mermin" title="N. David Mermin">Mermin, N. David</a> (January 1988). <a rel="nofollow" class="external text" href="http://aapt.scitation.org/doi/10.1119/1.15422">"E = mc2"</a>. <a href="/wiki/American_Journal_of_Physics" title="American Journal of Physics">American Journal of Physics</a>. 56 (1): 18–21. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1988AmJPh..56...18F">1988AmJPh..56...18F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.15422">10.1119/1.15422</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0002-9505">0002-9505</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Physics&rft.atitle=E+%3D+mc%3Csup%3E2%3C%2Fsup%3E&rft.volume=56&rft.issue=1&rft.pages=18-21&rft.date=1988-01&rft.issn=0002-9505&rft_id=info%3Adoi%2F10.1119%2F1.15422&rft_id=info%3Abibcode%2F1988AmJPh..56...18F&rft.aulast=Feigenbaum&rft.aufirst=Mitchell+J.&rft.au=Mermin%2C+N.+David&rft_id=http%3A%2F%2Faapt.scitation.org%2Fdoi%2F10.1119%2F1.15422&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUzanLeclercq2008" class="citation book cs1">Uzan, J-P; Leclercq, B (2008). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=dSAWX8TNpScC&pg=PA43">The Natural Laws of the Universe: Understanding Fundamental Constants</a>. Springer. pp. 43–44. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-387-73454-5" title="Special:BookSources/978-0-387-73454-5"><bdi>978-0-387-73454-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Natural+Laws+of+the+Universe%3A+Understanding+Fundamental+Constants&rft.pages=43-44&rft.pub=Springer&rft.date=2008&rft.isbn=978-0-387-73454-5&rft.aulast=Uzan&rft.aufirst=J-P&rft.au=Leclercq%2C+B&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DdSAWX8TNpScC%26pg%3DPA43&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-Yc-13"><a href="#cite_ref-Yc_13-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGibbs2004" class="citation web cs1">Gibbs, P. (2004) [1997]. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100325220247/http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/c.html">"Why is c the symbol for the speed of light?"</a>. Usenet Physics FAQ. <a href="/wiki/University_of_California,_Riverside" title="University of California, Riverside">University of California, Riverside</a>. Archived from <a rel="nofollow" class="external text" href="http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/c.html">the original</a> on 25 March 2010. Retrieved 16 November 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Usenet+Physics+FAQ&rft.atitle=Why+is+c+the+symbol+for+the+speed+of+light%3F&rft.date=2004&rft.aulast=Gibbs&rft.aufirst=P.&rft_id=http%3A%2F%2Fmath.ucr.edu%2Fhome%2Fbaez%2Fphysics%2FRelativity%2FSpeedOfLight%2Fc.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> "The origins of the letter c being used for the speed of light can be traced back to a paper of 1856 by Weber and Kohlrausch [...] Weber apparently meant c to stand for 'constant' in his force law, but there is evidence that physicists such as Lorentz and Einstein were accustomed to a common convention that c could be used as a variable for velocity. This usage can be traced back to the classic Latin texts in which c stood for 'celeritas', meaning 'speed'." </li> <li id="cite_note-14"><a href="#cite_ref-14">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMendelson2006" class="citation journal cs1">Mendelson, K. S. (2006). "The story of c". <a href="/wiki/American_Journal_of_Physics" title="American Journal of Physics">American Journal of Physics</a>. 74 (11): 995–997. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006AmJPh..74..995M">2006AmJPh..74..995M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.2238887">10.1119/1.2238887</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0002-9505">0002-9505</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Physics&rft.atitle=The+story+of+c&rft.volume=74&rft.issue=11&rft.pages=995-997&rft.date=2006&rft.issn=0002-9505&rft_id=info%3Adoi%2F10.1119%2F1.2238887&rft_id=info%3Abibcode%2F2006AmJPh..74..995M&rft.aulast=Mendelson&rft.aufirst=K.+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-handbook-15"><a href="#cite_ref-handbook_15-0">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLide2004" class="citation book cs1">Lide, D. R. (2004). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=WDll8hA006AC&q=speed+of+light+%22c0+OR+%22&pg=PT76">CRC Handbook of Chemistry and Physics</a>. <a href="/wiki/CRC_Press" title="CRC Press">CRC Press</a>. pp. 2–9. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8493-0485-9" title="Special:BookSources/978-0-8493-0485-9"><bdi>978-0-8493-0485-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=CRC+Handbook+of+Chemistry+and+Physics&rft.pages=2-9&rft.pub=CRC+Press&rft.date=2004&rft.isbn=978-0-8493-0485-9&rft.aulast=Lide&rft.aufirst=D.+R.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DWDll8hA006AC%26q%3Dspeed%2Bof%2Blight%2B%2522c0%2BOR%2B%2522%26pg%3DPT76&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHarris2002" class="citation book cs1">Harris, J. W.; et al. (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=c60mCxGRMR8C&q=speed+of+light+%22c0+OR+%22+date:2000-2009&pg=PA499">Handbook of Physics</a>. Springer. p. 499. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-387-95269-7" title="Special:BookSources/978-0-387-95269-7"><bdi>978-0-387-95269-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Handbook+of+Physics&rft.pages=499&rft.pub=Springer&rft.date=2002&rft.isbn=978-0-387-95269-7&rft.aulast=Harris&rft.aufirst=J.+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dc60mCxGRMR8C%26q%3Dspeed%2Bof%2Blight%2B%2522c0%2BOR%2B%2522%2Bdate%3A2000-2009%26pg%3DPA499&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWhitaker2005" class="citation book cs1">Whitaker, J. C. (2005). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=FdSQSAC3_EwC&q=speed+of+light+c0+handbook&pg=PA235">The Electronics Handbook</a>. CRC Press. p. 235. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8493-1889-4" title="Special:BookSources/978-0-8493-1889-4"><bdi>978-0-8493-1889-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Electronics+Handbook&rft.pages=235&rft.pub=CRC+Press&rft.date=2005&rft.isbn=978-0-8493-1889-4&rft.aulast=Whitaker&rft.aufirst=J.+C.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DFdSQSAC3_EwC%26q%3Dspeed%2Bof%2Blight%2Bc0%2Bhandbook%26pg%3DPA235&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCohen2007" class="citation book cs1">Cohen, E. R.; et al. (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=TElmhULQoeIC&q=speed+of+light+c0+handbook&pg=PA143">Quantities, Units and Symbols in Physical Chemistry</a> (3 ed.). <a href="/wiki/Royal_Society_of_Chemistry" title="Royal Society of Chemistry">Royal Society of Chemistry</a>. p. 184. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-85404-433-7" title="Special:BookSources/978-0-85404-433-7"><bdi>978-0-85404-433-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Quantities%2C+Units+and+Symbols+in+Physical+Chemistry&rft.pages=184&rft.edition=3&rft.pub=Royal+Society+of+Chemistry&rft.date=2007&rft.isbn=978-0-85404-433-7&rft.aulast=Cohen&rft.aufirst=E.+R.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DTElmhULQoeIC%26q%3Dspeed%2Bof%2Blight%2Bc0%2Bhandbook%26pg%3DPA143&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-BIPM_SI_units-16"><a href="#cite_ref-BIPM_SI_units_16-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFInternational_Bureau_of_Weights_and_Measures2006" class="citation cs2"><a href="/wiki/International_Bureau_of_Weights_and_Measures" title="International Bureau of Weights and Measures">International Bureau of Weights and Measures</a> (2006), <a rel="nofollow" class="external text" href="https://www.bipm.org/documents/20126/41483022/si_brochure_8.pdf">The International System of Units (SI)</a> (PDF) (8th ed.), p. 112, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/92-822-2213-6" title="Special:BookSources/92-822-2213-6"><bdi>92-822-2213-6</bdi></a>, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210604163219/https://www.bipm.org/documents/20126/41483022/si_brochure_8.pdf">archived</a> (PDF) from the original on 4 June 2021, retrieved 16 December 2021</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+International+System+of+Units+%28SI%29&rft.pages=112&rft.edition=8th&rft.date=2006&rft.isbn=92-822-2213-6&rft.au=International+Bureau+of+Weights+and+Measures&rft_id=https%3A%2F%2Fwww.bipm.org%2Fdocuments%2F20126%2F41483022%2Fsi_brochure_8.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-fixes-17">^ <a href="#cite_ref-fixes_17-0">a</a> <a href="#cite_ref-fixes_17-1">b</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSydenham2003" class="citation book cs1">Sydenham, P. H. (2003). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=sarHIbCVOUAC&pg=PA56">"Measurement of length"</a>. In Boyes, W (ed.). Instrumentation Reference Book (3 ed.). <a href="/wiki/Butterworth%E2%80%93Heinemann" class="mw-redirect" title="Butterworth–Heinemann">Butterworth–Heinemann</a>. p. 56. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7506-7123-1" title="Special:BookSources/978-0-7506-7123-1"><bdi>978-0-7506-7123-1</bdi></a>. <q>... if the speed of light is defined as a fixed number then, in principle, the time standard will serve as the length standard ...</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Measurement+of+length&rft.btitle=Instrumentation+Reference+Book&rft.pages=56&rft.edition=3&rft.pub=Butterworth%E2%80%93Heinemann&rft.date=2003&rft.isbn=978-0-7506-7123-1&rft.aulast=Sydenham&rft.aufirst=P.+H.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DsarHIbCVOUAC%26pg%3DPA56&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://physics.nist.gov/cgi-bin/cuu/Value?c">"CODATA value: Speed of Light in Vacuum"</a>. The NIST reference on Constants, Units, and Uncertainty. <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">NIST</a>. Retrieved 21 August 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+NIST+reference+on+Constants%2C+Units%2C+and+Uncertainty&rft.atitle=CODATA+value%3A+Speed+of+Light+in+Vacuum&rft_id=http%3A%2F%2Fphysics.nist.gov%2Fcgi-bin%2Fcuu%2FValue%3Fc&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJespersenFitz-RandolphRobb1999" class="citation book cs1">Jespersen, J.; Fitz-Randolph, J.; Robb, J. (1999). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Z7chuo4ebUAC&pg=PA280">From Sundials to Atomic Clocks: Understanding Time and Frequency</a> (Reprint of National Bureau of Standards 1977, 2nd ed.). <a href="/wiki/Courier_Dover" class="mw-redirect" title="Courier Dover">Courier Dover</a>. p. 280. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-486-40913-9" title="Special:BookSources/978-0-486-40913-9"><bdi>978-0-486-40913-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=From+Sundials+to+Atomic+Clocks%3A+Understanding+Time+and+Frequency&rft.pages=280&rft.edition=Reprint+of+National+Bureau+of+Standards+1977%2C+2nd&rft.pub=Courier+Dover&rft.date=1999&rft.isbn=978-0-486-40913-9&rft.aulast=Jespersen&rft.aufirst=J.&rft.au=Fitz-Randolph%2C+J.&rft.au=Robb%2C+J.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DZ7chuo4ebUAC%26pg%3DPA280&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-20"><a href="#cite_ref-20">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMermin2005" class="citation book cs1"><a href="/wiki/N._David_Mermin" title="N. David Mermin">Mermin, N. David</a> (2005). <a rel="nofollow" class="external text" href="https://www.worldcat.org/oclc/57283944">It's About Time: Understanding Einstein's Relativity</a>. Princeton: Princeton University Press. p. 22. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-691-12201-6" title="Special:BookSources/0-691-12201-6"><bdi>0-691-12201-6</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/57283944">57283944</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=It%27s+About+Time%3A+Understanding+Einstein%27s+Relativity&rft.place=Princeton&rft.pages=22&rft.pub=Princeton+University+Press&rft.date=2005&rft_id=info%3Aoclcnum%2F57283944&rft.isbn=0-691-12201-6&rft.aulast=Mermin&rft.aufirst=N.+David&rft_id=https%3A%2F%2Fwww.worldcat.org%2Foclc%2F57283944&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-21"><a href="#cite_ref-21">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://americanhistory.si.edu/collections/search/object/nmah_692464">"Nanoseconds Associated with Grace Hopper"</a>. <a href="/wiki/National_Museum_of_American_History" title="National Museum of American History">National Museum of American History</a>. Retrieved 1 March 2022. <q><a href="/wiki/Grace_Hopper" title="Grace Hopper">Grace Murray Hopper</a> (1906–1992), a mathematician who became a naval officer and computer scientist during World War II, started distributing these wire "nanoseconds" in the late 1960s in order to demonstrate how designing smaller components would produce faster computers.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=National+Museum+of+American+History&rft.atitle=Nanoseconds+Associated+with+Grace+Hopper&rft_id=https%3A%2F%2Famericanhistory.si.edu%2Fcollections%2Fsearch%2Fobject%2Fnmah_692464&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Lawrie-22"><a href="#cite_ref-Lawrie_22-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLawrie2002" class="citation book cs1">Lawrie, I. D. (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=9HZStxmfi3UC&pg=PA540">"Appendix C: Natural units"</a>. A Unified Grand Tour of Theoretical Physics (2 ed.). CRC Press. p. 540. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7503-0604-1" title="Special:BookSources/978-0-7503-0604-1"><bdi>978-0-7503-0604-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Appendix+C%3A+Natural+units&rft.btitle=A+Unified+Grand+Tour+of+Theoretical+Physics&rft.pages=540&rft.edition=2&rft.pub=CRC+Press&rft.date=2002&rft.isbn=978-0-7503-0604-1&rft.aulast=Lawrie&rft.aufirst=I.+D.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D9HZStxmfi3UC%26pg%3DPA540&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Hsu1-23"><a href="#cite_ref-Hsu1_23-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHsu2006" class="citation book cs1">Hsu, L. (2006). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=amLqckyrvUwC&pg=PA428">"Appendix A: Systems of units and the development of relativity theories"</a>. A Broader View of Relativity: General Implications of Lorentz and Poincaré Invariance (2 ed.). <a href="/wiki/World_Scientific" title="World Scientific">World Scientific</a>. pp. 427–428. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-981-256-651-5" title="Special:BookSources/978-981-256-651-5"><bdi>978-981-256-651-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Appendix+A%3A+Systems+of+units+and+the+development+of+relativity+theories&rft.btitle=A+Broader+View+of+Relativity%3A+General+Implications+of+Lorentz+and+Poincar%C3%A9+Invariance&rft.pages=427-428&rft.edition=2&rft.pub=World+Scientific&rft.date=2006&rft.isbn=978-981-256-651-5&rft.aulast=Hsu&rft.aufirst=L.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DamLqckyrvUwC%26pg%3DPA428&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-25"><a href="#cite_ref-25">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEinstein1905" class="citation journal cs1 cs1-prop-foreign-lang-source">Einstein, A. (1905). <a rel="nofollow" class="external text" href="http://sedici.unlp.edu.ar/handle/10915/2786">"Zur Elektrodynamik bewegter Körper"</a>. <a href="/wiki/Annalen_der_Physik" title="Annalen der Physik">Annalen der Physik</a> (Submitted manuscript) (in German). 17 (10): 890–921. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1905AnP...322..891E">1905AnP...322..891E</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fandp.19053221004">10.1002/andp.19053221004</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annalen+der+Physik&rft.atitle=Zur+Elektrodynamik+bewegter+K%C3%B6rper&rft.volume=17&rft.issue=10&rft.pages=890-921&rft.date=1905&rft_id=info%3Adoi%2F10.1002%2Fandp.19053221004&rft_id=info%3Abibcode%2F1905AnP...322..891E&rft.aulast=Einstein&rft.aufirst=A.&rft_id=http%3A%2F%2Fsedici.unlp.edu.ar%2Fhandle%2F10915%2F2786&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> English translation: <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPerrett" class="citation web cs1">Perrett, W. Walker, J (ed.). <a rel="nofollow" class="external text" href="http://www.fourmilab.ch/etexts/einstein/specrel/www/">"On the Electrodynamics of Moving Bodies"</a>. <a href="/wiki/Fourmilab" class="mw-redirect" title="Fourmilab">Fourmilab</a>. Translated by Jeffery, G. B. Retrieved 27 November 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Fourmilab&rft.atitle=On+the+Electrodynamics+of+Moving+Bodies&rft.aulast=Perrett&rft.aufirst=W.&rft_id=http%3A%2F%2Fwww.fourmilab.ch%2Fetexts%2Feinstein%2Fspecrel%2Fwww%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Hsu2-27">^ <a href="#cite_ref-Hsu2_27-0">a</a> <a href="#cite_ref-Hsu2_27-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHsuZhang2001" class="citation book cs1">Hsu, J.-P.; Zhang, Y. Z. (2001). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=jryk42J8oQIC&pg=RA1-PA541">Lorentz and Poincaré Invariance</a>. Advanced Series on Theoretical Physical Science. Vol. 8. <a href="/wiki/World_Scientific" title="World Scientific">World Scientific</a>. pp. 543ff. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-981-02-4721-8" title="Special:BookSources/978-981-02-4721-8"><bdi>978-981-02-4721-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Lorentz+and+Poincar%C3%A9+Invariance&rft.series=Advanced+Series+on+Theoretical+Physical+Science&rft.pages=543ff&rft.pub=World+Scientific&rft.date=2001&rft.isbn=978-981-02-4721-8&rft.aulast=Hsu&rft.aufirst=J.-P.&rft.au=Zhang%2C+Y.+Z.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Djryk42J8oQIC%26pg%3DRA1-PA541&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Zhang-28">^ <a href="#cite_ref-Zhang_28-0">a</a> <a href="#cite_ref-Zhang_28-1">b</a> <a href="#cite_ref-Zhang_28-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZhang1997" class="citation book cs1">Zhang, Y. Z. (1997). <a rel="nofollow" class="external text" href="https://archive.org/details/specialrelativit0000chan/page/172">Special Relativity and Its Experimental Foundations</a>. Advanced Series on Theoretical Physical Science. Vol. 4. <a href="/wiki/World_Scientific" title="World Scientific">World Scientific</a>. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/specialrelativit0000chan/page/172">172–173</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-981-02-2749-4" title="Special:BookSources/978-981-02-2749-4"><bdi>978-981-02-2749-4</bdi></a>. Retrieved 23 July 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Special+Relativity+and+Its+Experimental+Foundations&rft.series=Advanced+Series+on+Theoretical+Physical+Science&rft.pages=172-173&rft.pub=World+Scientific&rft.date=1997&rft.isbn=978-981-02-2749-4&rft.aulast=Zhang&rft.aufirst=Y.+Z.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fspecialrelativit0000chan%2Fpage%2F172&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-29"><a href="#cite_ref-29">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFd'Inverno1992" class="citation book cs1">d'Inverno, R. (1992). <a rel="nofollow" class="external text" href="https://archive.org/details/introducingeinst0000dinv/page/19">Introducing Einstein's Relativity</a>. Oxford University Press. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/introducingeinst0000dinv/page/19">19–20</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-859686-8" title="Special:BookSources/978-0-19-859686-8"><bdi>978-0-19-859686-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Introducing+Einstein%27s+Relativity&rft.pages=19-20&rft.pub=Oxford+University+Press&rft.date=1992&rft.isbn=978-0-19-859686-8&rft.aulast=d%27Inverno&rft.aufirst=R.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fintroducingeinst0000dinv%2Fpage%2F19&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-30"><a href="#cite_ref-30">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSriranjan2004" class="citation book cs1">Sriranjan, B. (2004). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=FsRfMvyudlAC&pg=PA20">"Postulates of the special theory of relativity and their consequences"</a>. The Special Theory to Relativity. PHI Learning Pvt. Ltd. pp. 20ff. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-81-203-1963-9" title="Special:BookSources/978-81-203-1963-9"><bdi>978-81-203-1963-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Postulates+of+the+special+theory+of+relativity+and+their+consequences&rft.btitle=The+Special+Theory+to+Relativity&rft.pages=20ff&rft.pub=PHI+Learning+Pvt.+Ltd.&rft.date=2004&rft.isbn=978-81-203-1963-9&rft.aulast=Sriranjan&rft.aufirst=B.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DFsRfMvyudlAC%26pg%3DPA20&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-:0-31">^ <a href="#cite_ref-:0_31-0">a</a> <a href="#cite_ref-:0_31-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEllisWilliams2000" class="citation book cs1"><a href="/wiki/George_F._R._Ellis" title="George F. R. Ellis">Ellis, George F. R.</a>; <a href="/wiki/Ruth_Margaret_Williams" title="Ruth Margaret Williams">Williams, Ruth M.</a> (2000). <a rel="nofollow" class="external text" href="https://www.worldcat.org/oclc/44694623">Flat and Curved Space-times</a> (2 ed.). Oxford: Oxford University Press. p. 12. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-19-850657-0" title="Special:BookSources/0-19-850657-0"><bdi>0-19-850657-0</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/44694623">44694623</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Flat+and+Curved+Space-times&rft.place=Oxford&rft.pages=12&rft.edition=2&rft.pub=Oxford+University+Press&rft.date=2000&rft_id=info%3Aoclcnum%2F44694623&rft.isbn=0-19-850657-0&rft.aulast=Ellis&rft.aufirst=George+F.+R.&rft.au=Williams%2C+Ruth+M.&rft_id=https%3A%2F%2Fwww.worldcat.org%2Foclc%2F44694623&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-32"><a href="#cite_ref-32">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAntonioliFienbergFleurotFukuda2004" class="citation journal cs1">Antonioli, Pietro; Fienberg, Richard Tresch; Fleurot, Fabrice; Fukuda, Yoshiyuki; Fulgione, Walter; Habig, Alec; Heise, Jaret; McDonald, Arthur B.; Mills, Corrinne; Namba, Toshio; Robinson, Leif J. (2 September 2004). <a rel="nofollow" class="external text" href="https://iopscience.iop.org/article/10.1088/1367-2630/6/1/114">"SNEWS: the SuperNova Early Warning System"</a>. <a href="/wiki/New_Journal_of_Physics" title="New Journal of Physics">New Journal of Physics</a>. 6: 114. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/astro-ph/0406214">astro-ph/0406214</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004NJPh....6..114A">2004NJPh....6..114A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F1367-2630%2F6%2F1%2F114">10.1088/1367-2630/6/1/114</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1367-2630">1367-2630</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:119431247">119431247</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=New+Journal+of+Physics&rft.atitle=SNEWS%3A+the+SuperNova+Early+Warning+System&rft.volume=6&rft.pages=114&rft.date=2004-09-02&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119431247%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2004NJPh....6..114A&rft_id=info%3Aarxiv%2Fastro-ph%2F0406214&rft.issn=1367-2630&rft_id=info%3Adoi%2F10.1088%2F1367-2630%2F6%2F1%2F114&rft.aulast=Antonioli&rft.aufirst=Pietro&rft.au=Fienberg%2C+Richard+Tresch&rft.au=Fleurot%2C+Fabrice&rft.au=Fukuda%2C+Yoshiyuki&rft.au=Fulgione%2C+Walter&rft.au=Habig%2C+Alec&rft.au=Heise%2C+Jaret&rft.au=McDonald%2C+Arthur+B.&rft.au=Mills%2C+Corrinne&rft.au=Namba%2C+Toshio&rft.au=Robinson%2C+Leif+J.&rft_id=https%3A%2F%2Fiopscience.iop.org%2Farticle%2F10.1088%2F1367-2630%2F6%2F1%2F114&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-34"><a href="#cite_ref-34">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRobertsSchleif2007" class="citation web cs1">Roberts, T.; Schleif, S. (2007). Dlugosz, J. M. (ed.). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20091015153529/http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html">"What is the experimental basis of Special Relativity?"</a>. Usenet Physics FAQ. <a href="/wiki/University_of_California,_Riverside" title="University of California, Riverside">University of California, Riverside</a>. Archived from <a rel="nofollow" class="external text" href="http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html">the original</a> on 15 October 2009. Retrieved 27 November 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Usenet+Physics+FAQ&rft.atitle=What+is+the+experimental+basis+of+Special+Relativity%3F&rft.date=2007&rft.aulast=Roberts&rft.aufirst=T.&rft.au=Schleif%2C+S.&rft_id=http%3A%2F%2Fmath.ucr.edu%2Fhome%2Fbaez%2Fphysics%2FRelativity%2FSR%2Fexperiments.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-35"><a href="#cite_ref-35">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTerrell1959" class="citation journal cs1">Terrell, J. (1959). "Invisibility of the Lorentz Contraction". <a href="/wiki/Physical_Review" title="Physical Review">Physical Review</a>. 116 (4): 1041–1045. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1959PhRv..116.1041T">1959PhRv..116.1041T</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.116.1041">10.1103/PhysRev.116.1041</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review&rft.atitle=Invisibility+of+the+Lorentz+Contraction&rft.volume=116&rft.issue=4&rft.pages=1041-1045&rft.date=1959&rft_id=info%3Adoi%2F10.1103%2FPhysRev.116.1041&rft_id=info%3Abibcode%2F1959PhRv..116.1041T&rft.aulast=Terrell&rft.aufirst=J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-36"><a href="#cite_ref-36">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPenrose1959" class="citation journal cs1">Penrose, R. (1959). "The Apparent Shape of a Relativistically Moving Sphere". <a href="/wiki/Proceedings_of_the_Cambridge_Philosophical_Society" class="mw-redirect" title="Proceedings of the Cambridge Philosophical Society">Proceedings of the Cambridge Philosophical Society</a>. 55 (1): 137–139. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1959PCPS...55..137P">1959PCPS...55..137P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1017%2FS0305004100033776">10.1017/S0305004100033776</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:123023118">123023118</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+Cambridge+Philosophical+Society&rft.atitle=The+Apparent+Shape+of+a+Relativistically+Moving+Sphere&rft.volume=55&rft.issue=1&rft.pages=137-139&rft.date=1959&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A123023118%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1017%2FS0305004100033776&rft_id=info%3Abibcode%2F1959PCPS...55..137P&rft.aulast=Penrose&rft.aufirst=R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-38"><a href="#cite_ref-38">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHartle2003" class="citation book cs1">Hartle, J. B. (2003). <a rel="nofollow" class="external text" href="https://archive.org/details/specialrelativit0000chan/page/52">Gravity: An Introduction to Einstein's General Relativity</a>. <a href="/wiki/Addison-Wesley" title="Addison-Wesley">Addison-Wesley</a>. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/specialrelativit0000chan/page/52">52–59</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-981-02-2749-4" title="Special:BookSources/978-981-02-2749-4"><bdi>978-981-02-2749-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Gravity%3A+An+Introduction+to+Einstein%27s+General+Relativity&rft.pages=52-59&rft.pub=Addison-Wesley&rft.date=2003&rft.isbn=978-981-02-2749-4&rft.aulast=Hartle&rft.aufirst=J.+B.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fspecialrelativit0000chan%2Fpage%2F52&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Hartle-39"><a href="#cite_ref-Hartle_39-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHartle2003" class="citation book cs1">Hartle, J. B. (2003). <a rel="nofollow" class="external text" href="https://archive.org/details/specialrelativit0000chan">Gravity: An Introduction to Einstein's General Relativity</a>. <a href="/wiki/Addison-Wesley" title="Addison-Wesley">Addison-Wesley</a>. p. 332. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-981-02-2749-4" title="Special:BookSources/978-981-02-2749-4"><bdi>978-981-02-2749-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Gravity%3A+An+Introduction+to+Einstein%27s+General+Relativity&rft.pages=332&rft.pub=Addison-Wesley&rft.date=2003&rft.isbn=978-981-02-2749-4&rft.aulast=Hartle&rft.aufirst=J.+B.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fspecialrelativit0000chan&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-40"><a href="#cite_ref-40">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAbbott2017" class="citation journal cs1">Abbott, B. P.; et al. (2017). <a rel="nofollow" class="external text" href="https://doi.org/10.3847%2F2041-8213%2Faa920c">"Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A"</a>. <a href="/wiki/The_Astrophysical_Journal_Letters" class="mw-redirect" title="The Astrophysical Journal Letters">The Astrophysical Journal Letters</a>. 848 (2): L13. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1710.05834">1710.05834</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2017ApJ...848L..13A">2017ApJ...848L..13A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.3847%2F2041-8213%2Faa920c">10.3847/2041-8213/aa920c</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal+Letters&rft.atitle=Gravitational+Waves+and+Gamma-Rays+from+a+Binary+Neutron+Star+Merger%3A+GW170817+and+GRB+170817A&rft.volume=848&rft.issue=2&rft.pages=L13&rft.date=2017&rft_id=info%3Aarxiv%2F1710.05834&rft_id=info%3Adoi%2F10.3847%2F2041-8213%2Faa920c&rft_id=info%3Abibcode%2F2017ApJ...848L..13A&rft.aulast=Abbott&rft.aufirst=B.+P.&rft_id=https%3A%2F%2Fdoi.org%2F10.3847%252F2041-8213%252Faa920c&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCornishBlasNardini2017" class="citation journal cs1">Cornish, Neil; Blas, Diego; Nardini, Germano (18 October 2017). <a rel="nofollow" class="external text" href="https://link.aps.org/doi/10.1103/PhysRevLett.119.161102">"Bounding the Speed of Gravity with Gravitational Wave Observations"</a>. <a href="/wiki/Physical_Review_Letters" title="Physical Review Letters">Physical Review Letters</a>. 119 (16): 161102. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1707.06101">1707.06101</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2017PhRvL.119p1102C">2017PhRvL.119p1102C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevLett.119.161102">10.1103/PhysRevLett.119.161102</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/29099221">29099221</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:206300556">206300556</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+Letters&rft.atitle=Bounding+the+Speed+of+Gravity+with+Gravitational+Wave+Observations&rft.volume=119&rft.issue=16&rft.pages=161102&rft.date=2017-10-18&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A206300556%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2017PhRvL.119p1102C&rft_id=info%3Aarxiv%2F1707.06101&rft_id=info%3Apmid%2F29099221&rft_id=info%3Adoi%2F10.1103%2FPhysRevLett.119.161102&rft.aulast=Cornish&rft.aufirst=Neil&rft.au=Blas%2C+Diego&rft.au=Nardini%2C+Germano&rft_id=https%3A%2F%2Flink.aps.org%2Fdoi%2F10.1103%2FPhysRevLett.119.161102&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLiuHeMikulskiPalenova2020" class="citation journal cs1">Liu, Xiaoshu; He, Vincent F.; Mikulski, Timothy M.; Palenova, Daria; Williams, Claire E.; Creighton, Jolien; Tasson, Jay D. (7 July 2020). <a rel="nofollow" class="external text" href="https://link.aps.org/doi/10.1103/PhysRevD.102.024028">"Measuring the speed of gravitational waves from the first and second observing run of Advanced LIGO and Advanced Virgo"</a>. <a href="/wiki/Physical_Review_D" class="mw-redirect" title="Physical Review D">Physical Review D</a>. 102 (2): 024028. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/2005.03121">2005.03121</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2020PhRvD.102b4028L">2020PhRvD.102b4028L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevD.102.024028">10.1103/PhysRevD.102.024028</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:220514677">220514677</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+D&rft.atitle=Measuring+the+speed+of+gravitational+waves+from+the+first+and+second+observing+run+of+Advanced+LIGO+and+Advanced+Virgo&rft.volume=102&rft.issue=2&rft.pages=024028&rft.date=2020-07-07&rft_id=info%3Aarxiv%2F2005.03121&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A220514677%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1103%2FPhysRevD.102.024028&rft_id=info%3Abibcode%2F2020PhRvD.102b4028L&rft.aulast=Liu&rft.aufirst=Xiaoshu&rft.au=He%2C+Vincent+F.&rft.au=Mikulski%2C+Timothy+M.&rft.au=Palenova%2C+Daria&rft.au=Williams%2C+Claire+E.&rft.au=Creighton%2C+Jolien&rft.au=Tasson%2C+Jay+D.&rft_id=https%3A%2F%2Flink.aps.org%2Fdoi%2F10.1103%2FPhysRevD.102.024028&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-Gibbs1997-41">^ <a href="#cite_ref-Gibbs1997_41-0">a</a> <a href="#cite_ref-Gibbs1997_41-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGibbs1997" class="citation web cs1">Gibbs, P. 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Retrieved 26 November 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Usenet+Physics+FAQ&rft.atitle=Is+The+Speed+of+Light+Constant%3F&rft.date=1997&rft.aulast=Gibbs&rft.aufirst=P.&rft_id=http%3A%2F%2Fmath.ucr.edu%2Fhome%2Fbaez%2Fphysics%2FRelativity%2FSpeedOfLight%2Fspeed_of_light.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Ellis_Uzan-42"><a href="#cite_ref-Ellis_Uzan_42-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEllisUzan2005" class="citation journal cs1">Ellis, G. F. R.; Uzan, J.-P. (2005). "'c' is the speed of light, isn't it?". <a href="/wiki/American_Journal_of_Physics" title="American Journal of Physics">American Journal of Physics</a>. 73 (3): 240–227. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/gr-qc/0305099">gr-qc/0305099</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2005AmJPh..73..240E">2005AmJPh..73..240E</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.1819929">10.1119/1.1819929</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:119530637">119530637</a>. <q>The possibility that the fundamental constants may vary during the evolution of the universe offers an exceptional window onto higher dimensional theories and is probably linked with the nature of the dark energy that makes the universe accelerate today.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Physics&rft.atitle=%27c%27+is+the+speed+of+light%2C+isn%27t+it%3F&rft.volume=73&rft.issue=3&rft.pages=240-227&rft.date=2005&rft_id=info%3Aarxiv%2Fgr-qc%2F0305099&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119530637%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1119%2F1.1819929&rft_id=info%3Abibcode%2F2005AmJPh..73..240E&rft.aulast=Ellis&rft.aufirst=G.+F.+R.&rft.au=Uzan%2C+J.-P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Mota-43"><a href="#cite_ref-Mota_43-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMota2006" class="citation thesis cs1">Mota, D. 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The Hong Kong University of Science and Technology. 19 July 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Hong+Kong+University+of+Science+and+Technology&rft.atitle=HKUST+Professors+Prove+Single+Photons+Do+Not+Exceed+the+Speed+of+Light&rft.date=2011-07-19&rft_id=http%3A%2F%2Fwww.ust.hk%2Feng%2Fnews%2Fpress_20110719-893.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFShanchao_ZhangJ._F._ChenChang_LiuM._M._T._Loy2011" class="citation journal cs1">Shanchao Zhang; J. F. Chen; Chang Liu; M. M. T. Loy; G. K. L. 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Laser Physics. 17 (5): 695–699. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/0706.0553">0706.0553</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2007LaPhy..17..695F">2007LaPhy..17..695F</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1134%2FS1054660X07050155">10.1134/S1054660X07050155</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1054-660X">1054-660X</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:61962">61962</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Laser+Physics&rft.atitle=Can+light+signals+travel+faster+than+c+in+nontrivial+vacua+in+flat+space-time%3F+Relativistic+causality+II&rft.volume=17&rft.issue=5&rft.pages=695-699&rft.date=2007-05&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A61962%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2007LaPhy..17..695F&rft_id=info%3Aarxiv%2F0706.0553&rft.issn=1054-660X&rft_id=info%3Adoi%2F10.1134%2FS1054660X07050155&rft.aulast=Fearn&rft.aufirst=H.&rft_id=http%3A%2F%2Flink.springer.com%2F10.1134%2FS1054660X07050155&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-51"><a href="#cite_ref-51">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLiberatiSonegoVisser2002" class="citation journal cs1">Liberati, S.; Sonego, S.; Visser, M. (2002). "Faster-than-c signals, special relativity, and causality". <a href="/wiki/Annals_of_Physics" title="Annals of Physics">Annals of Physics</a>. 298 (1): 167–185. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/gr-qc/0107091">gr-qc/0107091</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002AnPhy.298..167L">2002AnPhy.298..167L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1006%2Faphy.2002.6233">10.1006/aphy.2002.6233</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:48166">48166</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annals+of+Physics&rft.atitle=Faster-than-c+signals%2C+special+relativity%2C+and+causality&rft.volume=298&rft.issue=1&rft.pages=167-185&rft.date=2002&rft_id=info%3Aarxiv%2Fgr-qc%2F0107091&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A48166%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1006%2Faphy.2002.6233&rft_id=info%3Abibcode%2F2002AnPhy.298..167L&rft.aulast=Liberati&rft.aufirst=S.&rft.au=Sonego%2C+S.&rft.au=Visser%2C+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Taylor_p74-53"><a href="#cite_ref-Taylor_p74_53-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTaylorWheeler1992" class="citation book cs1"><a href="/wiki/Edwin_F._Taylor" title="Edwin F. Taylor">Taylor, E. F.</a>; <a href="/wiki/John_Archibald_Wheeler" title="John Archibald Wheeler">Wheeler, J. A.</a> (1992). <a rel="nofollow" class="external text" href="https://archive.org/details/spacetimephysics00edwi_0/page/74">Spacetime Physics</a>. W. H. Freeman. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/spacetimephysics00edwi_0/page/74">74–75</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7167-2327-1" title="Special:BookSources/978-0-7167-2327-1"><bdi>978-0-7167-2327-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Spacetime+Physics&rft.pages=74-75&rft.pub=W.+H.+Freeman&rft.date=1992&rft.isbn=978-0-7167-2327-1&rft.aulast=Taylor&rft.aufirst=E.+F.&rft.au=Wheeler%2C+J.+A.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fspacetimephysics00edwi_0%2Fpage%2F74&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-54"><a href="#cite_ref-54">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTolman2009" class="citation book cs1">Tolman, R. C. (2009) [1917]. "Velocities greater than that of light". The Theory of the Relativity of Motion (Reprint ed.). <a href="/wiki/BiblioLife" class="mw-redirect" title="BiblioLife">BiblioLife</a>. p. 54. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-103-17233-7" title="Special:BookSources/978-1-103-17233-7"><bdi>978-1-103-17233-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Velocities+greater+than+that+of+light&rft.btitle=The+Theory+of+the+Relativity+of+Motion&rft.pages=54&rft.edition=Reprint&rft.pub=BiblioLife&rft.date=2009&rft.isbn=978-1-103-17233-7&rft.aulast=Tolman&rft.aufirst=R.+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-55"><a href="#cite_ref-55">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHecht1987" class="citation book cs1">Hecht, E. (1987). Optics (2 ed.). Addison-Wesley. p. 62. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-201-11609-0" title="Special:BookSources/978-0-201-11609-0"><bdi>978-0-201-11609-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Optics&rft.pages=62&rft.edition=2&rft.pub=Addison-Wesley&rft.date=1987&rft.isbn=978-0-201-11609-0&rft.aulast=Hecht&rft.aufirst=E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-56"><a href="#cite_ref-56">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFQuimby2006" class="citation book cs1">Quimby, R. S. (2006). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=yWeDVfaVGxsC&pg=PA9">Photonics and lasers: an introduction</a>. John Wiley and Sons. p. 9. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-471-71974-8" title="Special:BookSources/978-0-471-71974-8"><bdi>978-0-471-71974-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Photonics+and+lasers%3A+an+introduction&rft.pages=9&rft.pub=John+Wiley+and+Sons&rft.date=2006&rft.isbn=978-0-471-71974-8&rft.aulast=Quimby&rft.aufirst=R.+S.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DyWeDVfaVGxsC%26pg%3DPA9&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-57"><a href="#cite_ref-57">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWertheim2007" class="citation news cs1">Wertheim, M. (20 June 2007). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2007/06/20/opinion/20wertheim.html?_r=1&scp=1&sq=%27the%20shadow%20goes%27&st=cse&oref=slogin">"The Shadow Goes"</a>. The New York Times. Retrieved 21 August 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+New+York+Times&rft.atitle=The+Shadow+Goes&rft.date=2007-06-20&rft.aulast=Wertheim&rft.aufirst=M.&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2007%2F06%2F20%2Fopinion%2F20wertheim.html%3F_r%3D1%26scp%3D1%26sq%3D%2527the%2520shadow%2520goes%2527%26st%3Dcse%26oref%3Dslogin&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Gibbs-58">^ <a href="#cite_ref-Gibbs_58-0">a</a> <a href="#cite_ref-Gibbs_58-1">b</a> <a href="#cite_ref-Gibbs_58-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGibbs1997" class="citation web cs1">Gibbs, P. (1997). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100310205556/http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html">"Is Faster-Than-Light Travel or Communication Possible?"</a>. Usenet Physics FAQ. <a href="/wiki/University_of_California,_Riverside" title="University of California, Riverside">University of California, Riverside</a>. Archived from <a rel="nofollow" class="external text" href="http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html">the original</a> on 10 March 2010. Retrieved 20 August 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Usenet+Physics+FAQ&rft.atitle=Is+Faster-Than-Light+Travel+or+Communication+Possible%3F&rft.date=1997&rft.aulast=Gibbs&rft.aufirst=P.&rft_id=http%3A%2F%2Fmath.ucr.edu%2Fhome%2Fbaez%2Fphysics%2FRelativity%2FSpeedOfLight%2FFTL.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-59"><a href="#cite_ref-59">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSakurai1994" class="citation book cs1"><a href="/wiki/J._J._Sakurai" title="J. J. Sakurai">Sakurai, J. J.</a> (1994). Tuan, S. F. (ed.). <a href="/wiki/Modern_Quantum_Mechanics" title="Modern Quantum Mechanics">Modern Quantum Mechanics</a> (Revised ed.). Addison-Wesley. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/modernquantummec00saku_488/page/n243">231</a>–232. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-201-53929-5" title="Special:BookSources/978-0-201-53929-5"><bdi>978-0-201-53929-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Modern+Quantum+Mechanics&rft.pages=231-232&rft.edition=Revised&rft.pub=Addison-Wesley&rft.date=1994&rft.isbn=978-0-201-53929-5&rft.aulast=Sakurai&rft.aufirst=J.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPeres1993" class="citation book cs1"><a href="/wiki/Asher_Peres" title="Asher Peres">Peres, Asher</a> (1993). <a href="/wiki/Quantum_Theory:_Concepts_and_Methods" title="Quantum Theory: Concepts and Methods">Quantum Theory: Concepts and Methods</a>. <a href="/wiki/Kluwer" class="mw-redirect" title="Kluwer">Kluwer</a>. p. 170. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7923-2549-4" title="Special:BookSources/0-7923-2549-4"><bdi>0-7923-2549-4</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/28854083">28854083</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Quantum+Theory%3A+Concepts+and+Methods&rft.pages=170&rft.pub=Kluwer&rft.date=1993&rft_id=info%3Aoclcnum%2F28854083&rft.isbn=0-7923-2549-4&rft.aulast=Peres&rft.aufirst=Asher&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCaves2015" class="citation book cs1"><a href="/wiki/Carlton_Caves" class="mw-redirect" title="Carlton Caves">Caves, Carlton M.</a> (2015). "Quantum Information Science: Emerging No More". OSA Century of Optics. <a href="/wiki/Optica_(society)" title="Optica (society)">Optica</a>. pp. 320–326. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1302.1864">1302.1864</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-943-58004-0" title="Special:BookSources/978-1-943-58004-0"><bdi>978-1-943-58004-0</bdi></a>. <q>[I]t was natural to dream that quantum correlations could be used for faster-than-light communication, but this speculation was quickly shot down, and the shooting established the principle that quantum states cannot be copied.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Quantum+Information+Science%3A+Emerging+No+More&rft.btitle=OSA+Century+of+Optics&rft.pages=320-326&rft.pub=Optica&rft.date=2015&rft_id=info%3Aarxiv%2F1302.1864&rft.isbn=978-1-943-58004-0&rft.aulast=Caves&rft.aufirst=Carlton+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-Muga-60"><a href="#cite_ref-Muga_60-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMugaMayatoEgusquiza2007" class="citation book cs1">Muga, J. G.; Mayato, R. S.; Egusquiza, I. L., eds. (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=InKru6zHQWgC&pg=PA48">Time in Quantum Mechanics</a>. Springer. p. 48. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-73472-7" title="Special:BookSources/978-3-540-73472-7"><bdi>978-3-540-73472-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Time+in+Quantum+Mechanics&rft.pages=48&rft.pub=Springer&rft.date=2007&rft.isbn=978-3-540-73472-7&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DInKru6zHQWgC%26pg%3DPA48&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Recami-61"><a href="#cite_ref-Recami_61-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHernández-FigueroaZamboni-RachedRecami2007" class="citation book cs1">Hernández-Figueroa, H. E.; Zamboni-Rached, M.; Recami, E. (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=xxbXgL967PwC&pg=PA26">Localized Waves</a>. <a href="/wiki/Wiley_Interscience" class="mw-redirect" title="Wiley Interscience">Wiley Interscience</a>. p. 26. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-470-10885-7" title="Special:BookSources/978-0-470-10885-7"><bdi>978-0-470-10885-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Localized+Waves&rft.pages=26&rft.pub=Wiley+Interscience&rft.date=2007&rft.isbn=978-0-470-10885-7&rft.aulast=Hern%C3%A1ndez-Figueroa&rft.aufirst=H.+E.&rft.au=Zamboni-Rached%2C+M.&rft.au=Recami%2C+E.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DxxbXgL967PwC%26pg%3DPA26&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Wynne-62"><a href="#cite_ref-Wynne_62-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWynne2002" class="citation journal cs1">Wynne, K. (2002). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090325093856/http://bcp.phys.strath.ac.uk/the_group/r/uf/2002-OC-causality.pdf">"Causality and the nature of information"</a> (PDF). <a href="/wiki/Optics_Communications" title="Optics Communications">Optics Communications</a>. 209 (1–3): 84–100. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002OptCo.209...85W">2002OptCo.209...85W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2FS0030-4018%2802%2901638-3">10.1016/S0030-4018(02)01638-3</a>. 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Retrieved 11 February 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature+News&rft.atitle=Embattled+neutrino+project+leaders+step+down&rft.date=2012-04-02&rft_id=info%3Adoi%2F10.1038%2Fnature.2012.10371&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A211730430%23id-name%3DS2CID&rft.aulast=Reich&rft.aufirst=Eugenie+Samuel&rft_id=http%3A%2F%2Fwww.nature.com%2Fnews%2Fembattled-neutrino-project-leaders-step-down-1.10371&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-66"><a href="#cite_ref-66">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOPERA_Collaboration2012" class="citation journal cs1"><a href="/wiki/OPERA_experiment" title="OPERA experiment">OPERA Collaboration</a> (12 July 2012). "Measurement of the neutrino velocity with the OPERA detector in the CNGS beam". <a href="/wiki/Journal_of_High_Energy_Physics" title="Journal of High Energy Physics">Journal of High Energy Physics</a>. 2012 (10): 93. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1109.4897">1109.4897</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2012JHEP...10..093A">2012JHEP...10..093A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FJHEP10%282012%29093">10.1007/JHEP10(2012)093</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:17652398">17652398</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+High+Energy+Physics&rft.atitle=Measurement+of+the+neutrino+velocity+with+the+OPERA+detector+in+the+CNGS+beam&rft.volume=2012&rft.issue=10&rft.pages=93&rft.date=2012-07-12&rft_id=info%3Aarxiv%2F1109.4897&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A17652398%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2FJHEP10%282012%29093&rft_id=info%3Abibcode%2F2012JHEP...10..093A&rft.au=OPERA+Collaboration&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Harrison-67"><a href="#cite_ref-Harrison_67-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHarrison2003" class="citation book cs1">Harrison, E. R. (2003). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=tSowGCP0kMIC&pg=PA206">Masks of the Universe</a>. Cambridge University Press. p. 206. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-77351-5" title="Special:BookSources/978-0-521-77351-5"><bdi>978-0-521-77351-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Masks+of+the+Universe&rft.pages=206&rft.pub=Cambridge+University+Press&rft.date=2003&rft.isbn=978-0-521-77351-5&rft.aulast=Harrison&rft.aufirst=E.+R.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DtSowGCP0kMIC%26pg%3DPA206&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-68"><a href="#cite_ref-68">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPanofskyPhillips1962" class="citation book cs1">Panofsky, W. K. H.; Phillips, M. 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Addison-Wesley. p. <a rel="nofollow" class="external text" href="https://archive.org/details/classicalelectri00pano_563/page/n192">182</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-201-05702-7" title="Special:BookSources/978-0-201-05702-7"><bdi>978-0-201-05702-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Classical+Electricity+and+Magnetism&rft.pages=182&rft.pub=Addison-Wesley&rft.date=1962&rft.isbn=978-0-201-05702-7&rft.aulast=Panofsky&rft.aufirst=W.+K.+H.&rft.au=Phillips%2C+M.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fclassicalelectri00pano_563&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-69"><a href="#cite_ref-69">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchaefer1999" class="citation journal cs1">Schaefer, B. E. (1999). 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Physical Review Letters. 98 (1): 010402. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/hep-ph/0306245">hep-ph/0306245</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2007PhRvL..98a0402A">2007PhRvL..98a0402A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevLett.98.010402">10.1103/PhysRevLett.98.010402</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17358459">17358459</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:31249827">31249827</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review+Letters&rft.atitle=Photon+Mass+Bound+Destroyed+by+Vortices&rft.volume=98&rft.issue=1&rft.pages=010402&rft.date=2007&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A31249827%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2007PhRvL..98a0402A&rft_id=info%3Aarxiv%2Fhep-ph%2F0306245&rft_id=info%3Apmid%2F17358459&rft_id=info%3Adoi%2F10.1103%2FPhysRevLett.98.010402&rft.aulast=Adelberger&rft.aufirst=E.&rft.au=Dvali%2C+G.&rft.au=Gruzinov%2C+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Sidharth-71"><a href="#cite_ref-Sidharth_71-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSidharth2008" class="citation book cs1">Sidharth, B. G. (2008). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=OUfHR36wSfAC&pg=PA134">The Thermodynamic Universe</a>. <a href="/wiki/World_Scientific" title="World Scientific">World Scientific</a>. p. 134. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-981-281-234-6" title="Special:BookSources/978-981-281-234-6"><bdi>978-981-281-234-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Thermodynamic+Universe&rft.pages=134&rft.pub=World+Scientific&rft.date=2008&rft.isbn=978-981-281-234-6&rft.aulast=Sidharth&rft.aufirst=B.+G.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DOUfHR36wSfAC%26pg%3DPA134&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-72"><a href="#cite_ref-72">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAmelino-Camelia2009" class="citation journal cs1">Amelino-Camelia, G. (2009). <a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F462291a">"Astrophysics: Burst of support for relativity"</a>. <a href="/wiki/Nature_(journal)" title="Nature (journal)">Nature</a>. 462 (7271): 291–292. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2009Natur.462..291A">2009Natur.462..291A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F462291a">10.1038/462291a</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19924200">19924200</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:205051022">205051022</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Astrophysics%3A+Burst+of+support+for+relativity&rft.volume=462&rft.issue=7271&rft.pages=291-292&rft.date=2009&rft_id=info%3Adoi%2F10.1038%2F462291a&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A205051022%23id-name%3DS2CID&rft_id=info%3Apmid%2F19924200&rft_id=info%3Abibcode%2F2009Natur.462..291A&rft.aulast=Amelino-Camelia&rft.aufirst=G.&rft_id=https%3A%2F%2Fdoi.org%2F10.1038%252F462291a&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Milonni-73">^ <a href="#cite_ref-Milonni_73-0">a</a> <a href="#cite_ref-Milonni_73-1">b</a> <a href="#cite_ref-Milonni_73-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMilonni2004" class="citation book cs1"><a href="/wiki/Peter_W._Milonni" title="Peter W. Milonni">Milonni, Peter W.</a> (2004). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=kE8OUCvt7ecC&pg=PA26">Fast light, slow light and left-handed light</a>. CRC Press. pp. 25 ff. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7503-0926-4" title="Special:BookSources/978-0-7503-0926-4"><bdi>978-0-7503-0926-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fast+light%2C+slow+light+and+left-handed+light&rft.pages=25+%27%27ff%27%27&rft.pub=CRC+Press&rft.date=2004&rft.isbn=978-0-7503-0926-4&rft.aulast=Milonni&rft.aufirst=Peter+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DkE8OUCvt7ecC%26pg%3DPA26&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Podesta-74"><a href="#cite_ref-Podesta_74-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFde_Podesta2002" class="citation book cs1">de Podesta, M. (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=h8BNvnR050cC&pg=PA131">Understanding the Properties of Matter</a>. CRC Press. p. 131. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-415-25788-6" title="Special:BookSources/978-0-415-25788-6"><bdi>978-0-415-25788-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Understanding+the+Properties+of+Matter&rft.pages=131&rft.pub=CRC+Press&rft.date=2002&rft.isbn=978-0-415-25788-6&rft.aulast=de+Podesta&rft.aufirst=M.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dh8BNvnR050cC%26pg%3DPA131&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-75"><a href="#cite_ref-75">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://refractiveindex.info/?shelf=main&book=H2O&page=Hale">"Optical constants of H2O, D2O (Water, heavy water, ice)"</a>. refractiveindex.info. Mikhail Polyanskiy. Retrieved 7 November 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=refractiveindex.info&rft.atitle=Optical+constants+of+H%3Csub%3E2%3C%2Fsub%3EO%2C+D%3Csub%3E2%3C%2Fsub%3EO+%28Water%2C+heavy+water%2C+ice%29&rft_id=https%3A%2F%2Frefractiveindex.info%2F%3Fshelf%3Dmain%26book%3DH2O%26page%3DHale&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-76"><a href="#cite_ref-76">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://refractiveindex.info/?shelf=glass&book=soda-lime&page=Rubin-clear">"Optical constants of Soda lime glass"</a>. refractiveindex.info. Mikhail Polyanskiy. Retrieved 7 November 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=refractiveindex.info&rft.atitle=Optical+constants+of+Soda+lime+glass&rft_id=https%3A%2F%2Frefractiveindex.info%2F%3Fshelf%3Dglass%26book%3Dsoda-lime%26page%3DRubin-clear&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-77"><a href="#cite_ref-77">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://refractiveindex.info/?shelf=main&book=C&page=Phillip">"Optical constants of C (Carbon, diamond, graphite)"</a>. refractiveindex.info. Mikhail Polyanskiy. Retrieved 7 November 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=refractiveindex.info&rft.atitle=Optical+constants+of+C+%28Carbon%2C+diamond%2C+graphite%29&rft_id=https%3A%2F%2Frefractiveindex.info%2F%3Fshelf%3Dmain%26book%3DC%26page%3DPhillip&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-78"><a href="#cite_ref-78">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCromie2001" class="citation web cs1">Cromie, William J. (24 January 2001). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20111028041346/http://www.news.harvard.edu/gazette/2001/01.24/01-stoplight.html">"Researchers now able to stop, restart light"</a>. Harvard University Gazette. Archived from <a rel="nofollow" class="external text" href="http://www.news.harvard.edu/gazette/2001/01.24/01-stoplight.html">the original</a> on 28 October 2011. Retrieved 8 November 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Harvard+University+Gazette&rft.atitle=Researchers+now+able+to+stop%2C+restart+light&rft.date=2001-01-24&rft.aulast=Cromie&rft.aufirst=William+J.&rft_id=http%3A%2F%2Fwww.news.harvard.edu%2Fgazette%2F2001%2F01.24%2F01-stoplight.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-79"><a href="#cite_ref-79">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMilonni2004" class="citation book cs1"><a href="/wiki/Peter_W._Milonni" title="Peter W. Milonni">Milonni, P. W.</a> (2004). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=kE8OUCvt7ecC&pg=PA25">Fast light, slow light and left-handed light</a>. CRC Press. p. 25. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7503-0926-4" title="Special:BookSources/978-0-7503-0926-4"><bdi>978-0-7503-0926-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fast+light%2C+slow+light+and+left-handed+light&rft.pages=25&rft.pub=CRC+Press&rft.date=2004&rft.isbn=978-0-7503-0926-4&rft.aulast=Milonni&rft.aufirst=P.+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DkE8OUCvt7ecC%26pg%3DPA25&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-80"><a href="#cite_ref-80">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFToll1956" class="citation journal cs1">Toll, J. S. (1956). "Causality and the Dispersion Relation: Logical Foundations". <a href="/wiki/Physical_Review" title="Physical Review">Physical Review</a>. 104 (6): 1760–1770. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1956PhRv..104.1760T">1956PhRv..104.1760T</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.104.1760">10.1103/PhysRev.104.1760</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physical+Review&rft.atitle=Causality+and+the+Dispersion+Relation%3A+Logical+Foundations&rft.volume=104&rft.issue=6&rft.pages=1760-1770&rft.date=1956&rft_id=info%3Adoi%2F10.1103%2FPhysRev.104.1760&rft_id=info%3Abibcode%2F1956PhRv..104.1760T&rft.aulast=Toll&rft.aufirst=J.+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-81"><a href="#cite_ref-81">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWolf2001" class="citation book cs1"><a href="/wiki/Emil_Wolf" title="Emil Wolf">Wolf, Emil</a> (2001). "Analyticity, Causality and Dispersion Relations". <a rel="nofollow" class="external text" href="https://www.worldcat.org/oclc/261134839">Selected Works of Emil Wolf: with commentary</a>. River Edge, N.J.: World Scientific. pp. 577–584. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-981-281-187-5" title="Special:BookSources/978-981-281-187-5"><bdi>978-981-281-187-5</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/261134839">261134839</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Analyticity%2C+Causality+and+Dispersion+Relations&rft.btitle=Selected+Works+of+Emil+Wolf%3A+with+commentary&rft.place=River+Edge%2C+N.J.&rft.pages=577-584&rft.pub=World+Scientific&rft.date=2001&rft_id=info%3Aoclcnum%2F261134839&rft.isbn=978-981-281-187-5&rft.aulast=Wolf&rft.aufirst=Emil&rft_id=https%3A%2F%2Fwww.worldcat.org%2Foclc%2F261134839&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-82"><a href="#cite_ref-82">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLibbrechtLibbrecht2006" class="citation journal cs1">Libbrecht, K. G.; Libbrecht, M. W. (December 2006). <a rel="nofollow" class="external text" href="https://authors.library.caltech.edu/12639/1/LIBajp06.pdf">"Interferometric measurement of the resonant absorption and refractive index in rubidium gas"</a> (PDF). American Journal of Physics. 74 (12): 1055–1060. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006AmJPh..74.1055L">2006AmJPh..74.1055L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.2335476">10.1119/1.2335476</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0002-9505">0002-9505</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Physics&rft.atitle=Interferometric+measurement+of+the+resonant+absorption+and+refractive+index+in+rubidium+gas&rft.volume=74&rft.issue=12&rft.pages=1055-1060&rft.date=2006-12&rft.issn=0002-9505&rft_id=info%3Adoi%2F10.1119%2F1.2335476&rft_id=info%3Abibcode%2F2006AmJPh..74.1055L&rft.aulast=Libbrecht&rft.aufirst=K.+G.&rft.au=Libbrecht%2C+M.+W.&rft_id=https%3A%2F%2Fauthors.library.caltech.edu%2F12639%2F1%2FLIBajp06.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-83"><a href="#cite_ref-83">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHauHarrisDuttonBehroozi1999" class="citation journal cs1"><a href="/wiki/Lene_Hau" title="Lene Hau">Hau, L. V.</a>; <a href="/wiki/Stephen_E._Harris" title="Stephen E. Harris">Harris, S. E.</a>; <a href="/wiki/Zachary_Dutton" title="Zachary Dutton">Dutton, Z.</a>; Behroozi, C. H. (1999). <a rel="nofollow" class="external text" href="http://www.seas.harvard.edu/haulab/publications/pdf/Slow_Light_1999.pdf">"Light speed reduction to 17 metres per second in an ultracold atomic gas"</a> (PDF). Nature. 397 (6720): 594–598. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1999Natur.397..594V">1999Natur.397..594V</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F17561">10.1038/17561</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4423307">4423307</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Light+speed+reduction+to+17+metres+per+second+in+an+ultracold+atomic+gas&rft.volume=397&rft.issue=6720&rft.pages=594-598&rft.date=1999&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4423307%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1038%2F17561&rft_id=info%3Abibcode%2F1999Natur.397..594V&rft.aulast=Hau&rft.aufirst=L.+V.&rft.au=Harris%2C+S.+E.&rft.au=Dutton%2C+Z.&rft.au=Behroozi%2C+C.+H.&rft_id=http%3A%2F%2Fwww.seas.harvard.edu%2Fhaulab%2Fpublications%2Fpdf%2FSlow_Light_1999.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLiuDuttonBehrooziHau2001" class="citation journal cs1">Liu, C.; <a href="/wiki/Zachary_Dutton" title="Zachary Dutton">Dutton, Z.</a>; Behroozi, C. H.; <a href="/wiki/Lene_Hau" title="Lene Hau">Hau, L. V.</a> (2001). <a rel="nofollow" class="external text" href="http://www.seas.harvard.edu/haulab/publications/pdf/Stopped_Light_2001.pdf">"Observation of coherent optical information storage in an atomic medium using halted light pulses"</a> (PDF). Nature. 409 (6819): 490–493. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2001Natur.409..490L">2001Natur.409..490L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F35054017">10.1038/35054017</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/11206540">11206540</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:1894748">1894748</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Observation+of+coherent+optical+information+storage+in+an+atomic+medium+using+halted+light+pulses&rft.volume=409&rft.issue=6819&rft.pages=490-493&rft.date=2001&rft_id=info%3Adoi%2F10.1038%2F35054017&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A1894748%23id-name%3DS2CID&rft_id=info%3Apmid%2F11206540&rft_id=info%3Abibcode%2F2001Natur.409..490L&rft.aulast=Liu&rft.aufirst=C.&rft.au=Dutton%2C+Z.&rft.au=Behroozi%2C+C.+H.&rft.au=Hau%2C+L.+V.&rft_id=http%3A%2F%2Fwww.seas.harvard.edu%2Fhaulab%2Fpublications%2Fpdf%2FStopped_Light_2001.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBajcsyZibrovLukin2003" class="citation journal cs1">Bajcsy, M.; Zibrov, A. 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Retrieved 8 December 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Physics+World&rft.atitle=Switching+light+on+and+off&rft.date=2003&rft.aulast=Dum%C3%A9&rft.aufirst=B.&rft_id=http%3A%2F%2Fphysicsworld.com%2Fcws%2Farticle%2Fnews%2F18724&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-84"><a href="#cite_ref-84">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChiao1993" class="citation journal cs1"><a href="/wiki/Raymond_Chiao" title="Raymond Chiao">Chiao, R. Y.</a> (1993). 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(19 July 2000). <a rel="nofollow" class="external text" href="http://news.bbc.co.uk/2/hi/science/nature/841690.stm">"Beam Smashes Light Barrier"</a>. BBC News. Retrieved 9 February 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=BBC+News&rft.atitle=Beam+Smashes+Light+Barrier&rft.date=2000-07-19&rft.aulast=Whitehouse&rft.aufirst=D.&rft_id=http%3A%2F%2Fnews.bbc.co.uk%2F2%2Fhi%2Fscience%2Fnature%2F841690.stm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGbur2008" class="citation web cs1"><a href="/wiki/Greg_Gbur" title="Greg Gbur">Gbur, Greg</a> (26 February 2008). <a rel="nofollow" class="external text" href="https://skullsinthestars.com/2008/02/26/light-breaking-its-own-speed-limit-how-superluminal-shenanigans-work/">"Light breaking its own speed limit: how 'superluminal' shenanigans work"</a>. Retrieved 9 February 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Light+breaking+its+own+speed+limit%3A+how+%27superluminal%27+shenanigans+work&rft.date=2008-02-26&rft.aulast=Gbur&rft.aufirst=Greg&rft_id=https%3A%2F%2Fskullsinthestars.com%2F2008%2F02%2F26%2Flight-breaking-its-own-speed-limit-how-superluminal-shenanigans-work%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> <li id="cite_note-85"><a href="#cite_ref-85">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCherenkov1934" class="citation journal cs1"><a href="/wiki/Pavel_Alekseyevich_Cherenkov" class="mw-redirect" title="Pavel Alekseyevich Cherenkov">Cherenkov, Pavel A.</a> (1934). "Видимое свечение чистых жидкостей под действием γ-радиации" [Visible emission of pure liquids by action of γ radiation]. <a href="/wiki/Doklady_Akademii_Nauk_SSSR" class="mw-redirect" title="Doklady Akademii Nauk SSSR">Doklady Akademii Nauk SSSR</a>. 2: 451.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Doklady+Akademii+Nauk+SSSR&rft.atitle=%D0%92%D0%B8%D0%B4%D0%B8%D0%BC%D0%BE%D0%B5+%D1%81%D0%B2%D0%B5%D1%87%D0%B5%D0%BD%D0%B8%D0%B5+%D1%87%D0%B8%D1%81%D1%82%D1%8B%D1%85+%D0%B6%D0%B8%D0%B4%D0%BA%D0%BE%D1%81%D1%82%D0%B5%D0%B9+%D0%BF%D0%BE%D0%B4+%D0%B4%D0%B5%D0%B9%D1%81%D1%82%D0%B2%D0%B8%D0%B5%D0%BC+%CE%B3-%D1%80%D0%B0%D0%B4%D0%B8%D0%B0%D1%86%D0%B8%D0%B8&rft.volume=2&rft.pages=451&rft.date=1934&rft.aulast=Cherenkov&rft.aufirst=Pavel+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> Reprinted: <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCherenkov1967" class="citation journal cs1">Cherenkov, P. A. (1967). "Видимое свечение чистых жидкостей под действием γ-радиации" [Visible emission of pure liquids by action of γ radiation]. Usp. Fiz. Nauk. 93 (10): 385. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.3367%2Fufnr.0093.196710n.0385">10.3367/ufnr.0093.196710n.0385</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Usp.+Fiz.+Nauk&rft.atitle=%D0%92%D0%B8%D0%B4%D0%B8%D0%BC%D0%BE%D0%B5+%D1%81%D0%B2%D0%B5%D1%87%D0%B5%D0%BD%D0%B8%D0%B5+%D1%87%D0%B8%D1%81%D1%82%D1%8B%D1%85+%D0%B6%D0%B8%D0%B4%D0%BA%D0%BE%D1%81%D1%82%D0%B5%D0%B9+%D0%BF%D0%BE%D0%B4+%D0%B4%D0%B5%D0%B9%D1%81%D1%82%D0%B2%D0%B8%D0%B5%D0%BC+%CE%B3-%D1%80%D0%B0%D0%B4%D0%B8%D0%B0%D1%86%D0%B8%D0%B8&rft.volume=93&rft.issue=10&rft.pages=385&rft.date=1967&rft_id=info%3Adoi%2F10.3367%2Fufnr.0093.196710n.0385&rft.aulast=Cherenkov&rft.aufirst=P.+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988">, and in <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFA._N._GorbunovE._P._Čerenkova1999" class="citation book cs1">A. 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Nature. 518 (7538): 161–163. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2015Natur.518..161B">2015Natur.518..161B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F518161a">10.1038/518161a</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/25673397">25673397</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Physics+in+finance%3A+Trading+at+the+speed+of+light&rft.volume=518&rft.issue=7538&rft.pages=161-163&rft.date=2015-02-11&rft_id=info%3Apmid%2F25673397&rft_id=info%3Adoi%2F10.1038%2F518161a&rft_id=info%3Abibcode%2F2015Natur.518..161B&rft.aulast=Buchanan&rft.aufirst=Mark&rft_id=https%3A%2F%2Fdoi.org%2F10.1038%252F518161a&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-92"><a href="#cite_ref-92">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.ft.com/cms/s/2/2bf37898-b775-11e2-841e-00144feabdc0.html">"Time is money when it comes to microwaves"</a>. 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The Apollo 8 Flight Journal. NASA. Archived from <a rel="nofollow" class="external text" href="https://history.nasa.gov/ap08fj/15day4_orbits789.htm">the original</a> on 4 January 2011. Retrieved 16 December 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Apollo+8+Flight+Journal&rft.atitle=Day+4%3A+Lunar+Orbits+7%2C+8+and+9&rft_id=https%3A%2F%2Fhistory.nasa.gov%2Fap08fj%2F15day4_orbits789.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-94"><a href="#cite_ref-94">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOrmston2012" class="citation web cs1">Ormston, Thomas (8 May 2012). <a rel="nofollow" class="external text" href="https://blogs.esa.int/mex/2012/08/05/time-delay-between-mars-and-earth/">"Time delay between Mars and Earth – Mars Express"</a>. MARS EXPRESS ESA’s mission to the Red Planet. Retrieved 16 July 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MARS+EXPRESS+ESA%E2%80%99s+mission+to+the+Red+Planet&rft.atitle=Time+delay+between+Mars+and+Earth+%E2%80%93+Mars+Express&rft.date=2012-05-08&rft.aulast=Ormston&rft.aufirst=Thomas&rft_id=https%3A%2F%2Fblogs.esa.int%2Fmex%2F2012%2F08%2F05%2Ftime-delay-between-mars-and-earth%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-95"><a href="#cite_ref-95">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFParisiPanontinWuMctigue2023" class="citation journal cs1">Parisi, Megan; Panontin, Tina; Wu, Shu-Chieh; Mctigue, Kaitlin; Vera, Alonso (2023). <a rel="nofollow" class="external text" href="https://openaccess.cms-conferences.org/publications/book/978-1-958651-74-2/article/978-1-958651-74-2_6">"Effects of Communication Delay on Human Spaceflight Missions"</a>. Human-Centered Aerospace Systems and Sustainability Applications. 98. AHFE Open Acces. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.54941%2Fahfe1003920">10.54941/ahfe1003920</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-958651-74-2" title="Special:BookSources/978-1-958651-74-2"><bdi>978-1-958651-74-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Human-Centered+Aerospace+Systems+and+Sustainability+Applications&rft.atitle=Effects+of+Communication+Delay+on+Human+Spaceflight+Missions&rft.volume=98&rft.date=2023&rft_id=info%3Adoi%2F10.54941%2Fahfe1003920&rft.isbn=978-1-958651-74-2&rft.aulast=Parisi&rft.aufirst=Megan&rft.au=Panontin%2C+Tina&rft.au=Wu%2C+Shu-Chieh&rft.au=Mctigue%2C+Kaitlin&rft.au=Vera%2C+Alonso&rft_id=https%3A%2F%2Fopenaccess.cms-conferences.org%2Fpublications%2Fbook%2F978-1-958651-74-2%2Farticle%2F978-1-958651-74-2_6&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Hubble-96">^ <a href="#cite_ref-Hubble_96-0">a</a> <a href="#cite_ref-Hubble_96-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation pressrelease cs1"><a rel="nofollow" class="external text" href="https://www.nasa.gov/mission_pages/hubble/science/undiscovered-country.html">"Hubble Reaches the "Undiscovered Country" of Primeval Galaxies"</a> (Press release). <a href="/wiki/Space_Telescope_Science_Institute" title="Space Telescope Science Institute">Space Telescope Science Institute</a>. 5 January 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Hubble+Reaches+the+%22Undiscovered+Country%22+of+Primeval+Galaxies&rft.pub=Space+Telescope+Science+Institute&rft.date=2010-01-05&rft_id=https%3A%2F%2Fwww.nasa.gov%2Fmission_pages%2Fhubble%2Fscience%2Fundiscovered-country.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-97"><a href="#cite_ref-97">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.nasa.gov/pdf/283957main_Hubble_Deep_Field_Lithograph.pdf">"The Hubble Ultra Deep Field Lithograph"</a> (PDF). NASA. Retrieved 4 February 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Hubble+Ultra+Deep+Field+Lithograph&rft.pub=NASA&rft_id=http%3A%2F%2Fwww.nasa.gov%2Fpdf%2F283957main_Hubble_Deep_Field_Lithograph.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-98"><a href="#cite_ref-98">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMack2021" class="citation book cs1"><a href="/wiki/Katie_Mack_(astrophysicist)" title="Katie Mack (astrophysicist)">Mack, Katie</a> (2021). <a rel="nofollow" class="external text" href="https://www.worldcat.org/oclc/1180972461">The End of Everything (Astrophysically Speaking)</a>. London: Penguin Books. pp. 18–19. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-141-98958-7" title="Special:BookSources/978-0-141-98958-7"><bdi>978-0-141-98958-7</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/1180972461">1180972461</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+End+of+Everything+%28Astrophysically+Speaking%29&rft.place=London&rft.pages=18-19&rft.pub=Penguin+Books&rft.date=2021&rft_id=info%3Aoclcnum%2F1180972461&rft.isbn=978-0-141-98958-7&rft.aulast=Mack&rft.aufirst=Katie&rft_id=https%3A%2F%2Fwww.worldcat.org%2Foclc%2F1180972461&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-99"><a href="#cite_ref-99">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.iau.org/public/measuring/">"The IAU and astronomical units"</a>. <a href="/wiki/International_Astronomical_Union" title="International Astronomical Union">International Astronomical Union</a>. 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Science. 265 (5171): 482–490. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1994Sci...265..482D">1994Sci...265..482D</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.265.5171.482">10.1126/science.265.5171.482</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17781305">17781305</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:10157934">10157934</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Lunar+Laser+Ranging%3A+A+Continuing+Legacy+of+the+Apollo+Program&rft.volume=265&rft.issue=5171&rft.pages=482-490&rft.date=1994-07&rft_id=info%3Adoi%2F10.1126%2Fscience.265.5171.482&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A10157934%23id-name%3DS2CID&rft_id=info%3Apmid%2F17781305&rft_id=info%3Abibcode%2F1994Sci...265..482D&rft.aulast=Dickey&rft.aufirst=J.+O.&rft_id=https%3A%2F%2Ftrs.jpl.nasa.gov%2Fbitstream%2F2014%2F32452%2F1%2F94-0193.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-cm26_181-102"><a href="#cite_ref-cm26_181_102-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStandish1982" class="citation journal cs1">Standish, E. 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B.; Bryant, S. H.; Kinman, P. W. (November 2007). <a rel="nofollow" class="external text" href="https://trs.jpl.nasa.gov/bitstream/2014/40972/1/07-0166.pdf">"Range Measurement as Practiced in the Deep Space Network"</a> (PDF). Proceedings of the IEEE. 95 (11): 2202–2214. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FJPROC.2007.905128">10.1109/JPROC.2007.905128</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:12149700">12149700</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+IEEE&rft.atitle=Range+Measurement+as+Practiced+in+the+Deep+Space+Network&rft.volume=95&rft.issue=11&rft.pages=2202-2214&rft.date=2007-11&rft_id=info%3Adoi%2F10.1109%2FJPROC.2007.905128&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A12149700%23id-name%3DS2CID&rft.aulast=Berner&rft.aufirst=J.+B.&rft.au=Bryant%2C+S.+H.&rft.au=Kinman%2C+P.+W.&rft_id=https%3A%2F%2Ftrs.jpl.nasa.gov%2Fbitstream%2F2014%2F40972%2F1%2F07-0166.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Resolution_1-104">^ <a href="#cite_ref-Resolution_1_104-0">a</a> <a href="#cite_ref-Resolution_1_104-1">b</a> <a href="#cite_ref-Resolution_1_104-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.bipm.org/en/committees/cg/cgpm/17-1983/resolution-1">"Resolution 1 of the 17th CGPM"</a>. BIPM. 1983. Retrieved 23 August 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Resolution+1+of+the+17th+CGPM&rft.pub=BIPM&rft.date=1983&rft_id=https%3A%2F%2Fwww.bipm.org%2Fen%2Fcommittees%2Fcg%2Fcgpm%2F17-1983%2Fresolution-1&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-cohen-105">^ <a href="#cite_ref-cohen_105-0">a</a> <a href="#cite_ref-cohen_105-1">b</a> <a href="#cite_ref-cohen_105-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="cohen-1940" class="citation journal cs1"><a href="/wiki/I._Bernard_Cohen" title="I. Bernard Cohen">Cohen, I. B.</a> (1940). <a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/imgsrv/download/pdf?id=uc1.b4375710;orient=0;size=100;seq=5;attachment=0">"Roemer and the first determination of the velocity of light (1676)"</a>. <a href="/wiki/Isis_(journal)" title="Isis (journal)">Isis</a>. 31 (2): 327–379. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F347594">10.1086/347594</a>. <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<a rel="nofollow" class="external text" href="https://hdl.handle.net/2027%2Fuc1.b4375710">2027/uc1.b4375710</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:145428377">145428377</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Isis&rft.atitle=Roemer+and+the+first+determination+of+the+velocity+of+light+%281676%29&rft.volume=31&rft.issue=2&rft.pages=327-379&rft.date=1940&rft_id=info%3Ahdl%2F2027%2Fuc1.b4375710&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A145428377%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1086%2F347594&rft.aulast=Cohen&rft.aufirst=I.+B.&rft_id=https%3A%2F%2Fbabel.hathitrust.org%2Fcgi%2Fimgsrv%2Fdownload%2Fpdf%3Fid%3Duc1.b4375710%3Borient%3D0%3Bsize%3D100%3Bseq%3D5%3Battachment%3D0&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-roemer-106">^ <a href="#cite_ref-roemer_106-0">a</a> <a href="#cite_ref-roemer_106-1">b</a> <a href="#cite_ref-roemer_106-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="roemer-1676" class="citation journal cs1 cs1-prop-foreign-lang-source"><a rel="nofollow" class="external text" href="http://www-obs.univ-lyon1.fr/labo/fc/ama09/pages_jdsc/pages/jdsc_1676_lumiere.pdf">"Demonstration tovchant le mouvement de la lumiere trouvé par M. Rŏmer de l'Académie Royale des Sciences"</a> [Demonstration to the movement of light found by Mr. Römer of the Royal Academy of Sciences] (PDF). <a href="/wiki/Journal_des_s%C3%A7avans" title="Journal des sçavans">Journal des sçavans</a> (in French): 233–236. 1676.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+des+s%C3%A7avans&rft.atitle=Demonstration+tovchant+le+mouvement+de+la+lumiere+trouv%C3%A9+par+M.+R%C5%8Fmer+de+l%27Acad%C3%A9mie+Royale+des+Sciences&rft.pages=233-236&rft.date=1676&rft_id=http%3A%2F%2Fwww-obs.univ-lyon1.fr%2Flabo%2Ffc%2Fama09%2Fpages_jdsc%2Fpages%2Fjdsc_1676_lumiere.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> Translated in <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="roemer-1676-EnglishTrans" class="citation journal cs1"><a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frstl.1677.0024">"A demonstration concerning the motion of light, communicated from Paris, in the Journal des Sçavans, and here made English"</a>. <a href="/wiki/Philosophical_Transactions_of_the_Royal_Society" title="Philosophical Transactions of the Royal Society">Philosophical Transactions of the Royal Society</a>. 12 (136): 893–895. 1677. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1677RSPT...12..893.">1677RSPT...12..893.</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frstl.1677.0024">10.1098/rstl.1677.0024</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Transactions+of+the+Royal+Society&rft.atitle=A+demonstration+concerning+the+motion+of+light%2C+communicated+from+Paris%2C+in+the+Journal+des+S%C3%A7avans%2C+and+here+made+English&rft.volume=12&rft.issue=136&rft.pages=893-895&rft.date=1677&rft_id=info%3Adoi%2F10.1098%2Frstl.1677.0024&rft_id=info%3Abibcode%2F1677RSPT...12..893.&rft_id=https%3A%2F%2Fdoi.org%2F10.1098%252Frstl.1677.0024&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> Reproduced in <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHuttonShawPearson1809" class="citation book cs1 cs1-prop-long-vol">Hutton, C.; Shaw, G.; Pearson, R., eds. (1809). <a rel="nofollow" class="external text" href="https://archive.org/stream/philosophicaltra02royarich#page/397/mode/1up">"On the Motion of Light by M. Romer"</a>. The Philosophical Transactions of the Royal Society of London, from Their Commencement in 1665, in the Year 1800: Abridged. Vol. II. From 1673 to 1682. London: C. & R. Baldwin. pp. 397–398.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=On+the+Motion+of+Light+by+M.+Romer&rft.btitle=The+Philosophical+Transactions+of+the+Royal+Society+of+London%2C+from+Their+Commencement+in+1665%2C+in+the+Year+1800%3A+Abridged&rft.place=London&rft.pages=397-398&rft.pub=C.+%26+R.+Baldwin&rft.date=1809&rft_id=https%3A%2F%2Farchive.org%2Fstream%2Fphilosophicaltra02royarich%23page%2F397%2Fmode%2F1up&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> The account published in Journal des sçavans was based on a report that Rømer read to the <a href="/wiki/French_Academy_of_Sciences" title="French Academy of Sciences">French Academy of Sciences</a> in November 1676 <a href="#cohen-1940">(Cohen, 1940, p. 346)</a>. </li> <li id="cite_note-Bradley1729-107">^ <a href="#cite_ref-Bradley1729_107-0">a</a> <a href="#cite_ref-Bradley1729_107-1">b</a> <a href="#cite_ref-Bradley1729_107-2">c</a> <a href="#cite_ref-Bradley1729_107-3">d</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBradley1729" class="citation journal cs1">Bradley, J. (1729). <a rel="nofollow" class="external text" href="http://gallica.bnf.fr/ark:/12148/bpt6k55840n.image.f375.langEN">"Account of a new discovered Motion of the Fix'd Stars"</a>. <a href="/wiki/Philosophical_Transactions" class="mw-redirect" title="Philosophical Transactions">Philosophical Transactions</a>. 35: 637–660.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Transactions&rft.atitle=Account+of+a+new+discovered+Motion+of+the+Fix%27d+Stars&rft.volume=35&rft.pages=637-660&rft.date=1729&rft.aulast=Bradley&rft.aufirst=J.&rft_id=http%3A%2F%2Fgallica.bnf.fr%2Fark%3A%2F12148%2Fbpt6k55840n.image.f375.langEN&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-108"><a href="#cite_ref-108">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDuffett-Smith1988" class="citation book cs1">Duffett-Smith, P. (1988). <a rel="nofollow" class="external text" href="https://archive.org/details/practicalastrono0000duff">Practical Astronomy with your Calculator</a>. Cambridge University Press. p. <a rel="nofollow" class="external text" href="https://archive.org/details/practicalastrono0000duff/page/62">62</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-35699-2" title="Special:BookSources/978-0-521-35699-2"><bdi>978-0-521-35699-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Practical+Astronomy+with+your+Calculator&rft.pages=62&rft.pub=Cambridge+University+Press&rft.date=1988&rft.isbn=978-0-521-35699-2&rft.aulast=Duffett-Smith&rft.aufirst=P.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fpracticalastrono0000duff&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://archive.org/details/practicalastrono0000duff/page/62">Extract of page 62</a>. </li> <li id="cite_note-AU_redef-109">^ <a href="#cite_ref-AU_redef_109-0">a</a> <a href="#cite_ref-AU_redef_109-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.iau.org/static/resolutions/IAU2012_English.pdf">"Resolution B2 on the re-definition of the astronomical unit of length"</a> (PDF). International Astronomical Union. 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Resolution+B2+on+the+re-definition+of+the+astronomical+unit+of+length&rft.pub=International+Astronomical+Union&rft.date=2012&rft_id=https%3A%2F%2Fwww.iau.org%2Fstatic%2Fresolutions%2FIAU2012_English.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-110"><a href="#cite_ref-110">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="http://www.bipm.org/utils/common/pdf/si_supplement_2014.pdf">"Supplement 2014: Updates to the 8th edition (2006) of the SI Brochure"</a> (PDF). The International System of Units. International Bureau of Weights and Measures: 14. 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+International+System+of+Units&rft.atitle=Supplement+2014%3A+Updates+to+the+8th+edition+%282006%29+of+the+SI+Brochure&rft.pages=14&rft.date=2014&rft_id=http%3A%2F%2Fwww.bipm.org%2Futils%2Fcommon%2Fpdf%2Fsi_supplement_2014.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-111"><a href="#cite_ref-111">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFInternational_Bureau_of_Weights_and_Measures2006" class="citation cs2"><a href="/wiki/International_Bureau_of_Weights_and_Measures" title="International Bureau of Weights and Measures">International Bureau of Weights and Measures</a> (2006), <a rel="nofollow" class="external text" href="https://www.bipm.org/documents/20126/41483022/si_brochure_8.pdf">The International System of Units (SI)</a> (PDF) (8th ed.), p. 126, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/92-822-2213-6" title="Special:BookSources/92-822-2213-6"><bdi>92-822-2213-6</bdi></a>, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210604163219/https://www.bipm.org/documents/20126/41483022/si_brochure_8.pdf">archived</a> (PDF) from the original on 4 June 2021, retrieved 16 December 2021</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+International+System+of+Units+%28SI%29&rft.pages=126&rft.edition=8th&rft.date=2006&rft.isbn=92-822-2213-6&rft.au=International+Bureau+of+Weights+and+Measures&rft_id=https%3A%2F%2Fwww.bipm.org%2Fdocuments%2F20126%2F41483022%2Fsi_brochure_8.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-113"><a href="#cite_ref-113">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrumfiel2012" class="citation journal cs1">Brumfiel, Geoff (14 September 2012). <a rel="nofollow" class="external text" href="https://www.nature.com/articles/nature.2012.11416">"The astronomical unit gets fixed"</a>. <a href="/wiki/Nature_(journal)" title="Nature (journal)">Nature</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature.2012.11416">10.1038/nature.2012.11416</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1476-4687">1476-4687</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:123424704">123424704</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=The+astronomical+unit+gets+fixed&rft.date=2012-09-14&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A123424704%23id-name%3DS2CID&rft.issn=1476-4687&rft_id=info%3Adoi%2F10.1038%2Fnature.2012.11416&rft.aulast=Brumfiel&rft.aufirst=Geoff&rft_id=https%3A%2F%2Fwww.nature.com%2Farticles%2Fnature.2012.11416&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-114"><a href="#cite_ref-114">^</a> See the following: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPitjevaStandish2009" class="citation journal cs1">Pitjeva, E. V.; Standish, E. M. (2009). <a rel="nofollow" class="external text" href="https://zenodo.org/record/1000691">"Proposals for the masses of the three largest asteroids, the Moon–Earth mass ratio and the Astronomical Unit"</a>. <a href="/wiki/Celestial_Mechanics_and_Dynamical_Astronomy" title="Celestial Mechanics and Dynamical Astronomy">Celestial Mechanics and Dynamical Astronomy</a>. 103 (4): 365–372. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2009CeMDA.103..365P">2009CeMDA.103..365P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs10569-009-9203-8">10.1007/s10569-009-9203-8</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:121374703">121374703</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Celestial+Mechanics+and+Dynamical+Astronomy&rft.atitle=Proposals+for+the+masses+of+the+three+largest+asteroids%2C+the+Moon%E2%80%93Earth+mass+ratio+and+the+Astronomical+Unit&rft.volume=103&rft.issue=4&rft.pages=365-372&rft.date=2009&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A121374703%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2Fs10569-009-9203-8&rft_id=info%3Abibcode%2F2009CeMDA.103..365P&rft.aulast=Pitjeva&rft.aufirst=E.+V.&rft.au=Standish%2C+E.+M.&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F1000691&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://ssd.jpl.nasa.gov/?constants">"Astrodynamic Constants"</a>. Solar System Dynamics. Jet Propulsion Laboratory. 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Archived from <a rel="nofollow" class="external text" href="http://maia.usno.navy.mil/NSFA/CBE.html">the original</a> on 8 December 2009. Retrieved 25 September 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=IAU+WG+on+NSFA+Current+Best+Estimates&rft.pub=US+Naval+Observatory&rft.au=IAU+Working+Group+on+Numerical+Standards+for+Fundamental+Astronomy&rft_id=http%3A%2F%2Fmaia.usno.navy.mil%2FNSFA%2FCBE.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-116"><a href="#cite_ref-116">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100831214704/http://www.npl.co.uk/educate-explore/posters/length/length-%28poster%29">"NPL's Beginner's Guide to Length"</a>. <a href="/wiki/National_Physical_Laboratory_(United_Kingdom)" title="National Physical Laboratory (United Kingdom)">UK National Physical Laboratory</a>. Archived from <a rel="nofollow" class="external text" href="http://www.npl.co.uk/educate-explore/posters/length/length-%28poster%29">the original</a> on 31 August 2010. Retrieved 28 October 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NPL%27s+Beginner%27s+Guide+to+Length&rft.pub=UK+National+Physical+Laboratory&rft_id=http%3A%2F%2Fwww.npl.co.uk%2Feducate-explore%2Fposters%2Flength%2Flength-%2528poster%2529&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-How-118">^ <a href="#cite_ref-How_118-0">a</a> <a href="#cite_ref-How_118-1">b</a> <a href="#cite_ref-How_118-2">c</a> <a href="#cite_ref-How_118-3">d</a> <a href="#cite_ref-How_118-4">e</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGibbs1997" class="citation web cs1">Gibbs, P. (1997). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20150821181850/http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/measure_c.html">"How is the speed of light measured?"</a>. Usenet Physics FAQ. University of California, Riverside. Archived from <a rel="nofollow" class="external text" href="http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/measure_c.html">the original</a> on 21 August 2015. Retrieved 13 January 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Usenet+Physics+FAQ&rft.atitle=How+is+the+speed+of+light+measured%3F&rft.date=1997&rft.aulast=Gibbs&rft.aufirst=P.&rft_id=http%3A%2F%2Fmath.ucr.edu%2Fhome%2Fbaez%2Fphysics%2FRelativity%2FSpeedOfLight%2Fmeasure_c.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-119"><a href="#cite_ref-119">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFowler" class="citation web cs1">Fowler, M. <a rel="nofollow" class="external text" href="http://galileoandeinstein.physics.virginia.edu/lectures/spedlite.html">"The Speed of Light"</a>. University of Virginia. Retrieved 21 April 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Speed+of+Light&rft.pub=University+of+Virginia&rft.aulast=Fowler&rft.aufirst=M.&rft_id=http%3A%2F%2Fgalileoandeinstein.physics.virginia.edu%2Flectures%2Fspedlite.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Hughes2012-120"><a href="#cite_ref-Hughes2012_120-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHughes2012" class="citation book cs1">Hughes, Stephan (2012). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=iZk5OOf7fVYC">Catchers of the Light: The Forgotten Lives of the Men and Women Who First Photographed the Heavens</a>. ArtDeCiel Publishing. p. 210. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-62050-961-6" title="Special:BookSources/978-1-62050-961-6"><bdi>978-1-62050-961-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Catchers+of+the+Light%3A+The+Forgotten+Lives+of+the+Men+and+Women+Who+First+Photographed+the+Heavens&rft.pages=210&rft.pub=ArtDeCiel+Publishing&rft.date=2012&rft.isbn=978-1-62050-961-6&rft.aulast=Hughes&rft.aufirst=Stephan&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DiZk5OOf7fVYC&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-121"><a href="#cite_ref-121">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCookeMartinMcCartneyWilf1968" class="citation journal cs1">Cooke, J.; Martin, M.; McCartney, H.; Wilf, B. (1968). "Direct determination of the speed of light as a general physics laboratory experiment". <a href="/wiki/American_Journal_of_Physics" title="American Journal of Physics">American Journal of Physics</a>. 36 (9): 847. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1968AmJPh..36..847C">1968AmJPh..36..847C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.1975166">10.1119/1.1975166</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Physics&rft.atitle=Direct+determination+of+the+speed+of+light+as+a+general+physics+laboratory+experiment&rft.volume=36&rft.issue=9&rft.pages=847&rft.date=1968&rft_id=info%3Adoi%2F10.1119%2F1.1975166&rft_id=info%3Abibcode%2F1968AmJPh..36..847C&rft.aulast=Cooke&rft.aufirst=J.&rft.au=Martin%2C+M.&rft.au=McCartney%2C+H.&rft.au=Wilf%2C+B.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAokiMitsui2008" class="citation journal cs1">Aoki, K.; Mitsui, T. (2008). "A small tabletop experiment for a direct measurement of the speed of light". <a href="/wiki/American_Journal_of_Physics" title="American Journal of Physics">American Journal of Physics</a>. 76 (9): 812–815. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/0705.3996">0705.3996</a>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2008AmJPh..76..812A">2008AmJPh..76..812A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.2919743">10.1119/1.2919743</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:117454437">117454437</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Physics&rft.atitle=A+small+tabletop+experiment+for+a+direct+measurement+of+the+speed+of+light&rft.volume=76&rft.issue=9&rft.pages=812-815&rft.date=2008&rft_id=info%3Aarxiv%2F0705.3996&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A117454437%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1119%2F1.2919743&rft_id=info%3Abibcode%2F2008AmJPh..76..812A&rft.aulast=Aoki&rft.aufirst=K.&rft.au=Mitsui%2C+T.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJamesOrmondStasch1999" class="citation journal cs1">James, M. B.; Ormond, R. B.; Stasch, A. J. (1999). 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Archive for History of Exact Sciences. 75 (2): 125–171. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs00407-020-00260-1">10.1007/s00407-020-00260-1</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1432-0657">1432-0657</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:253895826">253895826</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Archive+for+History+of+Exact+Sciences&rft.atitle=What+Heinrich+Hertz+discovered+about+electric+waves+in+1887%E2%80%931888&rft.volume=75&rft.issue=2&rft.pages=125-171&rft.date=2021-03-01&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A253895826%23id-name%3DS2CID&rft.issn=1432-0657&rft_id=info%3Adoi%2F10.1007%2Fs00407-020-00260-1&rft.aulast=Buchwald&rft.aufirst=Jed&rft.au=Yeang%2C+Chen-Pang&rft.au=Stemeroff%2C+Noah&rft.au=Barton%2C+Jenifer&rft.au=Harrington%2C+Quinn&rft_id=https%3A%2F%2Fdoi.org%2F10.1007%2Fs00407-020-00260-1&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-140"><a href="#cite_ref-140">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHertz1893" class="citation book cs1">Hertz, Heinrich (1893). Electric Waves. London: Macmillan and Co.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Electric+Waves&rft.place=London&rft.pub=Macmillan+and+Co.&rft.date=1893&rft.aulast=Hertz&rft.aufirst=Heinrich&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-141"><a href="#cite_ref-141">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichelson1927" class="citation journal cs1">Michelson, A. A. (1927). "Measurement of the Velocity of Light Between Mount Wilson and Mount San Antonio". The Astrophysical Journal. 65: 1. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1927ApJ....65....1M">1927ApJ....65....1M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F143021">10.1086/143021</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Measurement+of+the+Velocity+of+Light+Between+Mount+Wilson+and+Mount+San+Antonio&rft.volume=65&rft.pages=1&rft.date=1927&rft_id=info%3Adoi%2F10.1086%2F143021&rft_id=info%3Abibcode%2F1927ApJ....65....1M&rft.aulast=Michelson&rft.aufirst=A.+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-142"><a href="#cite_ref-142">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWeinerNunes2013" class="citation book cs1">Weiner, John; Nunes, Frederico (2013). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=ctpG-kmmK8kC">Light-Matter Interaction: Physics and Engineering at the Nanoscale</a> (illustrated ed.). OUP Oxford. p. 1. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-856766-0" title="Special:BookSources/978-0-19-856766-0"><bdi>978-0-19-856766-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Light-Matter+Interaction%3A+Physics+and+Engineering+at+the+Nanoscale&rft.pages=1&rft.edition=illustrated&rft.pub=OUP+Oxford&rft.date=2013&rft.isbn=978-0-19-856766-0&rft.aulast=Weiner&rft.aufirst=John&rft.au=Nunes%2C+Frederico&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DctpG-kmmK8kC&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://books.google.com/books?id=ctpG-kmmK8kC&pg=PA1">Extract of page 1</a>. </li> <li id="cite_note-143"><a href="#cite_ref-143">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSarton1993" class="citation book cs1"><a href="/wiki/George_Sarton" title="George Sarton">Sarton, G.</a> (1993). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=VcoGIKlHuZcC&pg=PA248">Ancient science through the golden age of Greece</a>. <a href="/wiki/Courier_Dover" class="mw-redirect" title="Courier Dover">Courier Dover</a>. p. 248. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-486-27495-9" title="Special:BookSources/978-0-486-27495-9"><bdi>978-0-486-27495-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Ancient+science+through+the+golden+age+of+Greece&rft.pages=248&rft.pub=Courier+Dover&rft.date=1993&rft.isbn=978-0-486-27495-9&rft.aulast=Sarton&rft.aufirst=G.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DVcoGIKlHuZcC%26pg%3DPA248&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Statistics-144">^ <a href="#cite_ref-Statistics_144-0">a</a> <a href="#cite_ref-Statistics_144-1">b</a> <a href="#cite_ref-Statistics_144-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMacKayOldford2000" class="citation journal cs1">MacKay, R. H.; Oldford, R. W. (2000). <a rel="nofollow" class="external text" href="http://sas.uwaterloo.ca/~rwoldfor/papers/sci-method/paperrev/">"Scientific Method, Statistical Method and the Speed of Light"</a>. <a href="/wiki/Statistical_Science_(journal)" class="mw-redirect" title="Statistical Science (journal)">Statistical Science</a>. 15 (3): 254–278. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1214%2Fss%2F1009212817">10.1214/ss/1009212817</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Statistical+Science&rft.atitle=Scientific+Method%2C+Statistical+Method+and+the+Speed+of+Light&rft.volume=15&rft.issue=3&rft.pages=254-278&rft.date=2000&rft_id=info%3Adoi%2F10.1214%2Fss%2F1009212817&rft.aulast=MacKay&rft.aufirst=R.+H.&rft.au=Oldford%2C+R.+W.&rft_id=http%3A%2F%2Fsas.uwaterloo.ca%2F~rwoldfor%2Fpapers%2Fsci-method%2Fpaperrev%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> (click on "Historical background" in the table of contents) </li> <li id="cite_note-145"><a href="#cite_ref-145">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAhmed2014" class="citation book cs1">Ahmed, Sherif Sayed (2014). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=ob79AgAAQBAJ">Electronic Microwave Imaging with Planar Multistatic Arrays</a>. Logos Verlag Berlin. p. 1. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-8325-3621-3" title="Special:BookSources/978-3-8325-3621-3"><bdi>978-3-8325-3621-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Electronic+Microwave+Imaging+with+Planar+Multistatic+Arrays&rft.pages=1&rft.pub=Logos+Verlag+Berlin&rft.date=2014&rft.isbn=978-3-8325-3621-3&rft.aulast=Ahmed&rft.aufirst=Sherif+Sayed&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dob79AgAAQBAJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://books.google.com/books?id=ob79AgAAQBAJ&pg=PA1">Extract of page 1</a> </li> <li id="cite_note-146"><a href="#cite_ref-146">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGross1999" class="citation journal cs1">Gross, C. G. (1999). "The Fire That Comes from the Eye". Neuroscientist. 5: 58–64. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1177%2F107385849900500108">10.1177/107385849900500108</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:84148912">84148912</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Neuroscientist&rft.atitle=The+Fire+That+Comes+from+the+Eye&rft.volume=5&rft.pages=58-64&rft.date=1999&rft_id=info%3Adoi%2F10.1177%2F107385849900500108&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A84148912%23id-name%3DS2CID&rft.aulast=Gross&rft.aufirst=C.+G.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Hamarneh-147"><a href="#cite_ref-Hamarneh_147-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHamarneh1972" class="citation journal cs1">Hamarneh, S. (1972). "Review: Hakim Mohammed Said, Ibn al-Haitham". <a href="/wiki/Isis_(journal)" title="Isis (journal)">Isis</a>. 63 (1): 119. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F350861">10.1086/350861</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Isis&rft.atitle=Review%3A+Hakim+Mohammed+Said%2C+Ibn+al-Haitham&rft.volume=63&rft.issue=1&rft.pages=119&rft.date=1972&rft_id=info%3Adoi%2F10.1086%2F350861&rft.aulast=Hamarneh&rft.aufirst=S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Lester-148">^ <a href="#cite_ref-Lester_148-0">a</a> <a href="#cite_ref-Lester_148-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLester2005" class="citation book cs1">Lester, P. M. (2005). Visual Communication: Images With Messages. <a href="/wiki/Thomson_Wadsworth" class="mw-redirect" title="Thomson Wadsworth">Thomson Wadsworth</a>. pp. 10–11. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-534-63720-0" title="Special:BookSources/978-0-534-63720-0"><bdi>978-0-534-63720-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Visual+Communication%3A+Images+With+Messages&rft.pages=10-11&rft.pub=Thomson+Wadsworth&rft.date=2005&rft.isbn=978-0-534-63720-0&rft.aulast=Lester&rft.aufirst=P.+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-149"><a href="#cite_ref-149">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFO'ConnorRobertson" class="citation web cs1"><a href="/wiki/John_J._O%27Connor_(mathematician)" class="mw-redirect" title="John J. O'Connor (mathematician)">O'Connor, J. J.</a>; <a href="/wiki/Edmund_F._Robertson" title="Edmund F. Robertson">Robertson, E. F.</a> <a rel="nofollow" class="external text" href="http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Haytham.html">"Abu Ali al-Hasan ibn al-Haytham"</a>. <a href="/wiki/MacTutor_History_of_Mathematics_archive" class="mw-redirect" title="MacTutor History of Mathematics archive">MacTutor History of Mathematics archive</a>. <a href="/wiki/University_of_St_Andrews" title="University of St Andrews">University of St Andrews</a>. Retrieved 12 January 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MacTutor+History+of+Mathematics+archive&rft.atitle=Abu+Ali+al-Hasan+ibn+al-Haytham&rft.aulast=O%27Connor&rft.aufirst=J.+J.&rft.au=Robertson%2C+E.+F.&rft_id=http%3A%2F%2Fwww-history.mcs.st-andrews.ac.uk%2FBiographies%2FAl-Haytham.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-150"><a href="#cite_ref-150">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLauginie2004" class="citation conference cs1">Lauginie, P. (2004). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20150704043700/http://sci-ed.org/documents/Lauginie-M.pdf">Measuring Speed of Light: Why? Speed of what?</a> (PDF). Fifth International Conference for History of Science in Science Education. Keszthely, Hungary. pp. 75–84. Archived from <a rel="nofollow" class="external text" href="http://sci-ed.org/documents/Lauginie-M.pdf">the original</a> (PDF) on 4 July 2015. Retrieved 12 August 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=Measuring+Speed+of+Light%3A+Why%3F+Speed+of+what%3F&rft.place=Keszthely%2C+Hungary&rft.pages=75-84&rft.date=2004&rft.aulast=Lauginie&rft.aufirst=P.&rft_id=http%3A%2F%2Fsci-ed.org%2Fdocuments%2FLauginie-M.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-151"><a href="#cite_ref-151">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFO'ConnorRobertson" class="citation web cs1">O'Connor, J. J.; Robertson, E. F. <a rel="nofollow" class="external text" href="http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Biruni.html">"Abu han Muhammad ibn Ahmad al-Biruni"</a>. MacTutor History of Mathematics archive. University of St Andrews. Retrieved 12 January 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MacTutor+History+of+Mathematics+archive&rft.atitle=Abu+han+Muhammad+ibn+Ahmad+al-Biruni&rft.aulast=O%27Connor&rft.aufirst=J.+J.&rft.au=Robertson%2C+E.+F.&rft_id=http%3A%2F%2Fwww-history.mcs.st-andrews.ac.uk%2FBiographies%2FAl-Biruni.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Lindberg-152"><a href="#cite_ref-Lindberg_152-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLindberg1996" class="citation book cs1">Lindberg, D. C. (1996). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=jSPHMKbjYkQC&pg=PA143">Roger Bacon and the origins of Perspectiva in the Middle Ages: a critical edition and English translation of Bacon's Perspectiva, with introduction and notes</a>. Oxford University Press. p. 143. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-823992-5" title="Special:BookSources/978-0-19-823992-5"><bdi>978-0-19-823992-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Roger+Bacon+and+the+origins+of+Perspectiva+in+the+Middle+Ages%3A+a+critical+edition+and+English+translation+of+Bacon%27s+Perspectiva%2C+with+introduction+and+notes&rft.pages=143&rft.pub=Oxford+University+Press&rft.date=1996&rft.isbn=978-0-19-823992-5&rft.aulast=Lindberg&rft.aufirst=D.+C.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DjSPHMKbjYkQC%26pg%3DPA143&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-153"><a href="#cite_ref-153">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLindberg1974" class="citation book cs1">Lindberg, D. C. (1974). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=fAPN_3w4hAUC&q=roger-bacon%20speed-of-light&pg=RA1-PA395">"Late Thirteenth-Century Synthesis in Optics"</a>. In Edward Grant (ed.). A source book in medieval science. Harvard University Press. p. 396. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-674-82360-0" title="Special:BookSources/978-0-674-82360-0"><bdi>978-0-674-82360-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Late+Thirteenth-Century+Synthesis+in+Optics&rft.btitle=A+source+book+in+medieval+science&rft.pages=396&rft.pub=Harvard+University+Press&rft.date=1974&rft.isbn=978-0-674-82360-0&rft.aulast=Lindberg&rft.aufirst=D.+C.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DfAPN_3w4hAUC%26q%3Droger-bacon%2520speed-of-light%26pg%3DRA1-PA395&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Marshall-154"><a href="#cite_ref-Marshall_154-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMarshall1981" class="citation journal cs1">Marshall, P. (1981). "Nicole Oresme on the Nature, Reflection, and Speed of Light". <a href="/wiki/Isis_(journal)" title="Isis (journal)">Isis</a>. 72 (3): 357–374 [367–374]. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F352787">10.1086/352787</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:144035661">144035661</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Isis&rft.atitle=Nicole+Oresme+on+the+Nature%2C+Reflection%2C+and+Speed+of+Light&rft.volume=72&rft.issue=3&rft.pages=357-374+367-374&rft.date=1981&rft_id=info%3Adoi%2F10.1086%2F352787&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A144035661%23id-name%3DS2CID&rft.aulast=Marshall&rft.aufirst=P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-155"><a href="#cite_ref-155">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSakellariadis1982" class="citation journal cs1">Sakellariadis, Spyros (1982). <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/41133639">"Descartes' Experimental Proof of the Infinite Velocity of Light and Huygens' Rejoinder"</a>. <a href="/wiki/Archive_for_History_of_Exact_Sciences" title="Archive for History of Exact Sciences">Archive for History of Exact Sciences</a>. 26 (1): 1–12. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF00348308">10.1007/BF00348308</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0003-9519">0003-9519</a>. <a href="/wiki/JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/41133639">41133639</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:118187860">118187860</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Archive+for+History+of+Exact+Sciences&rft.atitle=Descartes%27+Experimental+Proof+of+the+Infinite+Velocity+of+Light+and+Huygens%27+Rejoinder&rft.volume=26&rft.issue=1&rft.pages=1-12&rft.date=1982&rft.issn=0003-9519&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A118187860%23id-name%3DS2CID&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F41133639%23id-name%3DJSTOR&rft_id=info%3Adoi%2F10.1007%2FBF00348308&rft.aulast=Sakellariadis&rft.aufirst=Spyros&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F41133639&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-156"><a href="#cite_ref-156">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCajori1922" class="citation book cs1">Cajori, Florian (1922). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=XNtUAAAAYAAJ">A History of Physics in Its Elementary Branches: Including the Evolution of Physical Laboratories</a>. Macmillan. p. 76.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+History+of+Physics+in+Its+Elementary+Branches%3A+Including+the+Evolution+of+Physical+Laboratories&rft.pages=76&rft.pub=Macmillan&rft.date=1922&rft.aulast=Cajori&rft.aufirst=Florian&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DXNtUAAAAYAAJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-157"><a href="#cite_ref-157">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSmith1987" class="citation journal cs1">Smith, A. Mark (1987). <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/1006537">"Descartes's Theory of Light and Refraction: A Discourse on Method"</a>. <a href="/wiki/Transactions_of_the_American_Philosophical_Society" class="mw-redirect" title="Transactions of the American Philosophical Society">Transactions of the American Philosophical Society</a>. 77 (3): i–92. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.2307%2F1006537">10.2307/1006537</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0065-9746">0065-9746</a>. <a href="/wiki/JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/1006537">1006537</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Transactions+of+the+American+Philosophical+Society&rft.atitle=Descartes%27s+Theory+of+Light+and+Refraction%3A+A+Discourse+on+Method&rft.volume=77&rft.issue=3&rft.pages=i-92&rft.date=1987&rft.issn=0065-9746&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F1006537%23id-name%3DJSTOR&rft_id=info%3Adoi%2F10.2307%2F1006537&rft.aulast=Smith&rft.aufirst=A.+Mark&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F1006537&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-158"><a href="#cite_ref-158">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBoyer1959" class="citation book cs1"><a href="/wiki/Carl_Benjamin_Boyer" title="Carl Benjamin Boyer">Boyer, Carl Benjamin</a> (1959). The Rainbow: From Myth to Mathematics. Thomas Yoseloff. pp. 205–206. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/763848561">763848561</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Rainbow%3A+From+Myth+to+Mathematics&rft.pages=205-206&rft.pub=Thomas+Yoseloff&rft.date=1959&rft_id=info%3Aoclcnum%2F763848561&rft.aulast=Boyer&rft.aufirst=Carl+Benjamin&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-159"><a href="#cite_ref-159">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFoschiLeone2009" class="citation journal cs1">Foschi, Renato; Leone, Matteo (August 2009). <a rel="nofollow" class="external text" href="http://journals.sagepub.com/doi/10.1068/p6263">"Galileo, Measurement of the Velocity of Light, and the Reaction Times"</a>. Perception. 38 (8): 1251–1259. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1068%2Fp6263">10.1068/p6263</a>. <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<a rel="nofollow" class="external text" href="https://hdl.handle.net/2318%2F132957">2318/132957</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0301-0066">0301-0066</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19817156">19817156</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:11747908">11747908</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Perception&rft.atitle=Galileo%2C+Measurement+of+the+Velocity+of+Light%2C+and+the+Reaction+Times&rft.volume=38&rft.issue=8&rft.pages=1251-1259&rft.date=2009-08&rft_id=info%3Ahdl%2F2318%2F132957&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A11747908%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1068%2Fp6263&rft.issn=0301-0066&rft_id=info%3Apmid%2F19817156&rft.aulast=Foschi&rft.aufirst=Renato&rft.au=Leone%2C+Matteo&rft_id=http%3A%2F%2Fjournals.sagepub.com%2Fdoi%2F10.1068%2Fp6263&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-160"><a href="#cite_ref-160">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNewton1704" class="citation book cs1">Newton, I. (1704). "Prop. XI". <a rel="nofollow" class="external text" href="http://gallica.bnf.fr/ark:/12148/bpt6k3362k.image.f235.vignettesnaviguer">Optiks</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Prop.+XI&rft.btitle=Optiks&rft.date=1704&rft.aulast=Newton&rft.aufirst=I.&rft_id=http%3A%2F%2Fgallica.bnf.fr%2Fark%3A%2F12148%2Fbpt6k3362k.image.f235.vignettesnaviguer&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> The text of Prop. XI is identical between the first (1704) and second (1719) editions. </li> <li id="cite_note-guarnieri_7-1-161"><a href="#cite_ref-guarnieri_7-1_161-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGuarnieri2015" class="citation journal cs1">Guarnieri, M. (2015). "Two Millennia of Light: The Long Path to Maxwell's Waves". IEEE Industrial Electronics Magazine. 9 (2): 54–56, 60. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FMIE.2015.2421754">10.1109/MIE.2015.2421754</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:20759821">20759821</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Industrial+Electronics+Magazine&rft.atitle=Two+Millennia+of+Light%3A+The+Long+Path+to+Maxwell%27s+Waves&rft.volume=9&rft.issue=2&rft.pages=54-56%2C+60&rft.date=2015&rft_id=info%3Adoi%2F10.1109%2FMIE.2015.2421754&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A20759821%23id-name%3DS2CID&rft.aulast=Guarnieri&rft.aufirst=M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-162"><a href="#cite_ref-162">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKirchhoff1857" class="citation journal cs1">Kirchhoff, G. (1857). <a rel="nofollow" class="external text" href="http://gallica.bnf.fr/ark:/12148/bpt6k15187j/f549.item.r=">"Über die Bewegung der Elektricität"</a>. <a href="/wiki/Annalen_der_Physik" title="Annalen der Physik">Ann. Phys.</a> 178 (12): 529–244. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1857AnP...178..529K">1857AnP...178..529K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fandp.18571781203">10.1002/andp.18571781203</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Ann.+Phys.&rft.atitle=%C3%9Cber+die+Bewegung+der+Elektricit%C3%A4t&rft.volume=178&rft.issue=12&rft.pages=529-244&rft.date=1857&rft_id=info%3Adoi%2F10.1002%2Fandp.18571781203&rft_id=info%3Abibcode%2F1857AnP...178..529K&rft.aulast=Kirchhoff&rft.aufirst=G.&rft_id=http%3A%2F%2Fgallica.bnf.fr%2Fark%3A%2F12148%2Fbpt6k15187j%2Ff549.item.r%3D&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-163"><a href="#cite_ref-163">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGiordano2009" class="citation book cs1">Giordano, Nicholas J. (2009). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=BwistUlpZ7cC">College physics: reasoning and relationships</a>. Cengage Learning. p. 787. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-534-42471-8" title="Special:BookSources/978-0-534-42471-8"><bdi>978-0-534-42471-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=College+physics%3A+reasoning+and+relationships&rft.pages=787&rft.pub=Cengage+Learning&rft.date=2009&rft.isbn=978-0-534-42471-8&rft.aulast=Giordano&rft.aufirst=Nicholas+J.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DBwistUlpZ7cC&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://books.google.com/books?id=BwistUlpZ7cC&pg=PA787">Extract of page 787</a></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBergmann1992" class="citation book cs1">Bergmann, Peter Gabriel (1992). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=WYxkrwMidp0C">The riddle of gravitation</a>. Courier Dover Publications. p. 17. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-486-27378-5" title="Special:BookSources/978-0-486-27378-5"><bdi>978-0-486-27378-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+riddle+of+gravitation&rft.pages=17&rft.pub=Courier+Dover+Publications&rft.date=1992&rft.isbn=978-0-486-27378-5&rft.aulast=Bergmann&rft.aufirst=Peter+Gabriel&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DWYxkrwMidp0C&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://books.google.com/books?id=WYxkrwMidp0C&pg=PA17">Extract of page 17</a></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBais2005" class="citation book cs1">Bais, Sander (2005). <a rel="nofollow" class="external text" href="https://archive.org/details/equationsiconsof0000bais">The equations: icons of knowledge</a>. Harvard University Press. p. <a rel="nofollow" class="external text" href="https://archive.org/details/equationsiconsof0000bais/page/40">40</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-674-01967-6" title="Special:BookSources/978-0-674-01967-6"><bdi>978-0-674-01967-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+equations%3A+icons+of+knowledge&rft.pages=40&rft.pub=Harvard+University+Press&rft.date=2005&rft.isbn=978-0-674-01967-6&rft.aulast=Bais&rft.aufirst=Sander&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fequationsiconsof0000bais&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <a rel="nofollow" class="external text" href="https://archive.org/details/equationsiconsof0000bais/page/40">Extract of page 40</a></li></ul> </li> <li id="cite_note-maxwellbio-164"><a href="#cite_ref-maxwellbio_164-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFO'ConnorRobertson1997" class="citation web cs1">O'Connor, J. J.; Robertson, E. F. (November 1997). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110128034939/http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Maxwell.html">"James Clerk Maxwell"</a>. School of Mathematics and Statistics, <a href="/wiki/University_of_St_Andrews" title="University of St Andrews">University of St Andrews</a>. Archived from <a rel="nofollow" class="external text" href="http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Maxwell.html">the original</a> on 28 January 2011. Retrieved 13 October 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=James+Clerk+Maxwell&rft.pub=School+of+Mathematics+and+Statistics%2C+University+of+St+Andrews&rft.date=1997-11&rft.aulast=O%27Connor&rft.aufirst=J.+J.&rft.au=Robertson%2C+E.+F.&rft_id=http%3A%2F%2Fwww-groups.dcs.st-and.ac.uk%2F~history%2FBiographies%2FMaxwell.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-165"><a href="#cite_ref-165">^</a> Campbell, Lewis; Garnett, William; Rautio, James C. "The Life of James Clerk Maxwell", p. 544, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-77375-139-9" title="Special:BookSources/978-1-77375-139-9">978-1-77375-139-9</a>. </li> <li id="cite_note-166"><a href="#cite_ref-166">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWatson1957" class="citation journal cs1">Watson, E. C. (1 September 1957). <a rel="nofollow" class="external text" href="https://doi.org/10.1119/1.1934460">"On the Relations between Light and Electricity"</a>. American Journal of Physics. 25 (6): 335–343. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1957AmJPh..25..335W">1957AmJPh..25..335W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.1934460">10.1119/1.1934460</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0002-9505">0002-9505</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Physics&rft.atitle=On+the+Relations+between+Light+and+Electricity&rft.volume=25&rft.issue=6&rft.pages=335-343&rft.date=1957-09-01&rft.issn=0002-9505&rft_id=info%3Adoi%2F10.1119%2F1.1934460&rft_id=info%3Abibcode%2F1957AmJPh..25..335W&rft.aulast=Watson&rft.aufirst=E.+C.&rft_id=https%3A%2F%2Fdoi.org%2F10.1119%2F1.1934460&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-167"><a href="#cite_ref-167">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFConsoliPluchino2018" class="citation book cs1">Consoli, Maurizio; Pluchino, Alessandro (2018). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=VdWEDwAAQBAJ&pg=PA118">Michelson-Morley Experiments: An Enigma for Physics & The History of Science</a>. World Scientific. pp. 118–119. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-9-813-27818-9" title="Special:BookSources/978-9-813-27818-9"><bdi>978-9-813-27818-9</bdi></a>. Retrieved 4 May 2020.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Michelson-Morley+Experiments%3A+An+Enigma+for+Physics+%26+The+History+of+Science&rft.pages=118-119&rft.pub=World+Scientific&rft.date=2018&rft.isbn=978-9-813-27818-9&rft.aulast=Consoli&rft.aufirst=Maurizio&rft.au=Pluchino%2C+Alessandro&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DVdWEDwAAQBAJ%26pg%3DPA118&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-168"><a href="#cite_ref-168">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichelsonMorley1887" class="citation journal cs1">Michelson, A. A.; Morley, E. W. (1887). <a rel="nofollow" class="external text" href="https://zenodo.org/record/1450078">"On the Relative Motion of the Earth and the Luminiferous Ether"</a>. <a href="/wiki/American_Journal_of_Science" title="American Journal of Science">American Journal of Science</a>. 34 (203): 333–345. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1366%2F0003702874447824">10.1366/0003702874447824</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:98374065">98374065</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=American+Journal+of+Science&rft.atitle=On+the+Relative+Motion+of+the+Earth+and+the+Luminiferous+Ether&rft.volume=34&rft.issue=203&rft.pages=333-345&rft.date=1887&rft_id=info%3Adoi%2F10.1366%2F0003702874447824&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A98374065%23id-name%3DS2CID&rft.aulast=Michelson&rft.aufirst=A.+A.&rft.au=Morley%2C+E.+W.&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F1450078&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-169"><a href="#cite_ref-169">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFrench1983" class="citation book cs1">French, A. P. (1983). Special relativity. Van Nostrand Reinhold. pp. 51–57. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-442-30782-0" title="Special:BookSources/978-0-442-30782-0"><bdi>978-0-442-30782-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Special+relativity&rft.pages=51-57&rft.pub=Van+Nostrand+Reinhold&rft.date=1983&rft.isbn=978-0-442-30782-0&rft.aulast=French&rft.aufirst=A.+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-170"><a href="#cite_ref-170">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDarrigol2000" class="citation book cs1">Darrigol, O. (2000). <a rel="nofollow" class="external text" href="https://archive.org/details/electrodynamicsf0000darr">Electrodynamics from Ampére to Einstein</a>. Clarendon Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-850594-5" title="Special:BookSources/978-0-19-850594-5"><bdi>978-0-19-850594-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Electrodynamics+from+Amp%C3%A9re+to+Einstein&rft.pub=Clarendon+Press&rft.date=2000&rft.isbn=978-0-19-850594-5&rft.aulast=Darrigol&rft.aufirst=O.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Felectrodynamicsf0000darr&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-171"><a href="#cite_ref-171">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGalison2003" class="citation book cs1"><a href="/wiki/Peter_Galison" title="Peter Galison">Galison, P.</a> (2003). Einstein's Clocks, Poincaré's Maps: Empires of Time. W. W. Norton. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-393-32604-8" title="Special:BookSources/978-0-393-32604-8"><bdi>978-0-393-32604-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Einstein%27s+Clocks%2C+Poincar%C3%A9%27s+Maps%3A+Empires+of+Time&rft.pub=W.+W.+Norton&rft.date=2003&rft.isbn=978-0-393-32604-8&rft.aulast=Galison&rft.aufirst=P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-172"><a href="#cite_ref-172">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMiller1981" class="citation book cs1">Miller, A. I. (1981). <a rel="nofollow" class="external text" href="https://archive.org/details/alberteinsteinss0000mill">Albert Einstein's special theory of relativity. Emergence (1905) and early interpretation (1905–1911)</a>. Addison–Wesley. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-201-04679-3" title="Special:BookSources/978-0-201-04679-3"><bdi>978-0-201-04679-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Albert+Einstein%27s+special+theory+of+relativity.+Emergence+%281905%29+and+early+interpretation+%281905%E2%80%931911%29&rft.pub=Addison%E2%80%93Wesley&rft.date=1981&rft.isbn=978-0-201-04679-3&rft.aulast=Miller&rft.aufirst=A.+I.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Falberteinsteinss0000mill&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-173"><a href="#cite_ref-173">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPais1982" class="citation book cs1"><a href="/wiki/Abraham_Pais" title="Abraham Pais">Pais, A.</a> (1982). <a href="/wiki/Subtle_is_the_Lord:_The_Science_and_the_Life_of_Albert_Einstein" class="mw-redirect" title="Subtle is the Lord: The Science and the Life of Albert Einstein">Subtle is the Lord: The Science and the Life of Albert Einstein</a>. Oxford University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-520438-4" title="Special:BookSources/978-0-19-520438-4"><bdi>978-0-19-520438-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Subtle+is+the+Lord%3A+The+Science+and+the+Life+of+Albert+Einstein&rft.pub=Oxford+University+Press&rft.date=1982&rft.isbn=978-0-19-520438-4&rft.aulast=Pais&rft.aufirst=A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-13thCGPMr1-174"><a href="#cite_ref-13thCGPMr1_174-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20210411132806/https://www.bipm.org/en/CGPM/db/13/1/">"Resolution 1 of the 15th CGPM"</a>. <a href="/wiki/International_Bureau_of_Weights_and_Measures" title="International Bureau of Weights and Measures">BIPM</a>. 1967. Archived from <a rel="nofollow" class="external text" href="https://www.bipm.org/en/CGPM/db/13/1/">the original</a> on 11 April 2021. Retrieved 14 March 2021.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Resolution+1+of+the+15th+CGPM&rft.pub=BIPM&rft.date=1967&rft_id=https%3A%2F%2Fwww.bipm.org%2Fen%2FCGPM%2Fdb%2F13%2F1%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-11thCGPM-175"><a href="#cite_ref-11thCGPM_175-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.bipm.org/en/CGPM/db/11/6/">"Resolution 6 of the 15th CGPM"</a>. <a href="/wiki/International_Bureau_of_Weights_and_Measures" title="International Bureau of Weights and Measures">BIPM</a>. 1967. Retrieved 13 October 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Resolution+6+of+the+15th+CGPM&rft.pub=BIPM&rft.date=1967&rft_id=http%3A%2F%2Fwww.bipm.org%2Fen%2FCGPM%2Fdb%2F11%2F6%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-176"><a href="#cite_ref-176">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBargerHall1973" class="citation journal cs1">Barger, R.; Hall, J. (1973). "Wavelength of the 3.39-μm laser-saturated absorption line of methane". Applied Physics Letters. 22 (4): 196. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1973ApPhL..22..196B">1973ApPhL..22..196B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1063%2F1.1654608">10.1063/1.1654608</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:1841238">1841238</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Applied+Physics+Letters&rft.atitle=Wavelength+of+the+3.39-%CE%BCm+laser-saturated+absorption+line+of+methane&rft.volume=22&rft.issue=4&rft.pages=196&rft.date=1973&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A1841238%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1063%2F1.1654608&rft_id=info%3Abibcode%2F1973ApPhL..22..196B&rft.aulast=Barger&rft.aufirst=R.&rft.au=Hall%2C+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-15thCGPM-178"><a href="#cite_ref-15thCGPM_178-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.bipm.org/en/CGPM/db/15/2/">"Resolution 2 of the 15th CGPM"</a>. BIPM. 1975. Retrieved 9 September 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Resolution+2+of+the+15th+CGPM&rft.pub=BIPM&rft.date=1975&rft_id=http%3A%2F%2Fwww.bipm.org%2Fen%2FCGPM%2Fdb%2F15%2F2%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Wheeler-179"><a href="#cite_ref-Wheeler_179-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTaylorWheeler1992" class="citation book cs1"><a href="/wiki/Edwin_F._Taylor" title="Edwin F. Taylor">Taylor, E. F.</a>; <a href="/wiki/John_Archibald_Wheeler" title="John Archibald Wheeler">Wheeler, J. A.</a> (1992). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=PDA8YcvMc_QC&pg=PA59">Spacetime Physics: Introduction to Special Relativity</a> (2 ed.). Macmillan. p. 59. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7167-2327-1" title="Special:BookSources/978-0-7167-2327-1"><bdi>978-0-7167-2327-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Spacetime+Physics%3A+Introduction+to+Special+Relativity&rft.pages=59&rft.edition=2&rft.pub=Macmillan&rft.date=1992&rft.isbn=978-0-7167-2327-1&rft.aulast=Taylor&rft.aufirst=E.+F.&rft.au=Wheeler%2C+J.+A.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DPDA8YcvMc_QC%26pg%3DPA59&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-timeline-180"><a href="#cite_ref-timeline_180-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPenzes2009" class="citation web cs1">Penzes, W. B. (2009). <a rel="nofollow" class="external text" href="https://www.nist.gov/pml/div683/upload/museum-timeline.pdf">"Time Line for the Definition of the Meter"</a> (PDF). <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">NIST</a>. Retrieved 11 January 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Time+Line+for+the+Definition+of+the+Meter&rft.pub=NIST&rft.date=2009&rft.aulast=Penzes&rft.aufirst=W.+B.&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Fdiv683%2Fupload%2Fmuseum-timeline.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-Adams-181"><a href="#cite_ref-Adams_181-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAdams1997" class="citation book cs1">Adams, S. (1997). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=1RV0AysEN4oC&pg=PA140">Relativity: An Introduction to Space–Time Physics</a>. CRC Press. p. 140. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7484-0621-0" title="Special:BookSources/978-0-7484-0621-0"><bdi>978-0-7484-0621-0</bdi></a>. <q>One peculiar consequence of this system of definitions is that any future refinement in our ability to measure c will not change the speed of light (which is a defined number), but will change the length of the meter!</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Relativity%3A+An+Introduction+to+Space%E2%80%93Time+Physics&rft.pages=140&rft.pub=CRC+Press&rft.date=1997&rft.isbn=978-0-7484-0621-0&rft.aulast=Adams&rft.aufirst=S.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D1RV0AysEN4oC%26pg%3DPA140&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-W_Rindler-182"><a href="#cite_ref-W_Rindler_182-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRindler2006" class="citation book cs1">Rindler, W. (2006). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=MuuaG5HXOGEC&pg=PT41">Relativity: Special, General, and Cosmological</a> (2 ed.). Oxford University Press. p. 41. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-856731-8" title="Special:BookSources/978-0-19-856731-8"><bdi>978-0-19-856731-8</bdi></a>. <q>Note that [...] improvements in experimental accuracy will modify the meter relative to atomic wavelengths, but not the value of the speed of light!</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Relativity%3A+Special%2C+General%2C+and+Cosmological&rft.pages=41&rft.edition=2&rft.pub=Oxford+University+Press&rft.date=2006&rft.isbn=978-0-19-856731-8&rft.aulast=Rindler&rft.aufirst=W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DMuuaG5HXOGEC%26pg%3DPT41&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-183"><a href="#cite_ref-183">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140811195806/http://www.bipm.org/en/si/new_si/explicit_constant.html">"The "explicit-constant" formulation"</a>. BIPM. 2011. Archived from <a rel="nofollow" class="external text" href="http://www.bipm.org/en/si/new_si/explicit_constant.html">the original</a> on 11 August 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=BIPM&rft.atitle=The+%22explicit-constant%22+formulation&rft.date=2011&rft_id=http%3A%2F%2Fwww.bipm.org%2Fen%2Fsi%2Fnew_si%2Fexplicit_constant.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> </li> <li id="cite_note-184"><a href="#cite_ref-184">^</a> See, for example: <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFConover2016" class="citation web cs1"><a href="/wiki/Emily_Conover" title="Emily Conover">Conover, Emily</a> (2 November 2016). <a rel="nofollow" class="external text" href="https://www.sciencenews.org/article/units-measure-are-getting-fundamental-upgrade">"Units of measure are getting a fundamental upgrade"</a>. <a href="/wiki/Science_News" title="Science News">Science News</a>. Retrieved 6 February 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Science+News&rft.atitle=Units+of+measure+are+getting+a+fundamental+upgrade&rft.date=2016-11-02&rft.aulast=Conover&rft.aufirst=Emily&rft_id=https%3A%2F%2Fwww.sciencenews.org%2Farticle%2Funits-measure-are-getting-fundamental-upgrade&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKnottsMohrPhillips2017" class="citation journal cs1">Knotts, Sandra; Mohr, Peter J.; Phillips, William D. (January 2017). <a rel="nofollow" class="external text" href="http://scitation.aip.org/content/aapt/journal/tpt/55/1/10.1119/1.4972491">"An Introduction to the New SI"</a>. <a href="/wiki/The_Physics_Teacher" title="The Physics Teacher">The Physics Teacher</a>. 55 (1): 16–21. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2017PhTea..55...16K">2017PhTea..55...16K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1119%2F1.4972491">10.1119/1.4972491</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0031-921X">0031-921X</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:117581000">117581000</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Physics+Teacher&rft.atitle=An+Introduction+to+the+New+SI&rft.volume=55&rft.issue=1&rft.pages=16-21&rft.date=2017-01&rft_id=info%3Adoi%2F10.1119%2F1.4972491&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A117581000%23id-name%3DS2CID&rft.issn=0031-921X&rft_id=info%3Abibcode%2F2017PhTea..55...16K&rft.aulast=Knotts&rft.aufirst=Sandra&rft.au=Mohr%2C+Peter+J.&rft.au=Phillips%2C+William+D.&rft_id=http%3A%2F%2Fscitation.aip.org%2Fcontent%2Faapt%2Fjournal%2Ftpt%2F55%2F1%2F10.1119%2F1.4972491&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/si-redefinition">"SI Redefinition"</a>. <a href="/wiki/National_Institute_of_Standards_and_Technology" title="National Institute of Standards and Technology">National Institute of Standards and Technology</a>. 11 May 2018. Retrieved 6 February 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=National+Institute+of+Standards+and+Technology&rft.atitle=SI+Redefinition&rft.date=2018-05-11&rft_id=https%3A%2F%2Fwww.nist.gov%2Fsi-redefinition&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2></div> <div class="mw-heading mw-heading3"><h3 id="Historical_references">Historical references</h3></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin" style=""> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRømer1676" class="citation journal cs1 cs1-prop-foreign-lang-source"><a href="/wiki/Ole_R%C3%B8mer" title="Ole Rømer">Rømer, O.</a> (1676). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20220908221513/http://www.ffn.ub.es/luisnavarro/nuevo_maletin/Roemer_1676.pdf">"Démonstration touchant le mouvement de la lumière trouvé par M. Römer de l'Academie Royale des Sciences"</a> (PDF). <a href="/wiki/Journal_des_s%C3%A7avans" title="Journal des sçavans">Journal des sçavans</a> (in French): 223–236. Archived from <a rel="nofollow" class="external text" href="http://www.ffn.ub.es/luisnavarro/nuevo_maletin/Roemer_1676.pdf">the original</a> (PDF) on 8 September 2022. Retrieved 10 March 2020.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+des+s%C3%A7avans&rft.atitle=D%C3%A9monstration+touchant+le+mouvement+de+la+lumi%C3%A8re+trouv%C3%A9+par+M.+R%C3%B6mer+de+l%27Academie+Royale+des+Sciences&rft.pages=223-236&rft.date=1676&rft.aulast=R%C3%B8mer&rft.aufirst=O.&rft_id=http%3A%2F%2Fwww.ffn.ub.es%2Fluisnavarro%2Fnuevo_maletin%2FRoemer_1676.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"> <ul><li>Translated as <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20070729214326/http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Roemer-1677/Roemer-1677.html">"A Demonstration concerning the Motion of Light"</a>. <a href="/wiki/Philosophical_Transactions_of_the_Royal_Society" title="Philosophical Transactions of the Royal Society">Philosophical Transactions of the Royal Society</a>. 12 (136): 893–894. 1677. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1677RSPT...12..893.">1677RSPT...12..893.</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frstl.1677.0024">10.1098/rstl.1677.0024</a>. Archived from <a rel="nofollow" class="external text" href="http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Roemer-1677/Roemer-1677.html">the original</a> on 29 July 2007.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Transactions+of+the+Royal+Society&rft.atitle=A+Demonstration+concerning+the+Motion+of+Light&rft.volume=12&rft.issue=136&rft.pages=893-894&rft.date=1677&rft_id=info%3Adoi%2F10.1098%2Frstl.1677.0024&rft_id=info%3Abibcode%2F1677RSPT...12..893.&rft_id=http%3A%2F%2Fdbhs.wvusd.k12.ca.us%2Fwebdocs%2FChem-History%2FRoemer-1677%2FRoemer-1677.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHalley1694" class="citation journal cs1"><a href="/wiki/Edmond_Halley" title="Edmond Halley">Halley, E.</a> (1694). <a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frstl.1694.0048">"Monsieur Cassini, his New and Exact Tables for the Eclipses of the First Satellite of Jupiter, reduced to the Julian Stile and Meridian of London"</a>. <a href="/wiki/Philosophical_Transactions_of_the_Royal_Society" title="Philosophical Transactions of the Royal Society">Philosophical Transactions of the Royal Society</a>. 18 (214): 237–256. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1694RSPT...18..237C">1694RSPT...18..237C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frstl.1694.0048">10.1098/rstl.1694.0048</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Transactions+of+the+Royal+Society&rft.atitle=Monsieur+Cassini%2C+his+New+and+Exact+Tables+for+the+Eclipses+of+the+First+Satellite+of+Jupiter%2C+reduced+to+the+Julian+Stile+and+Meridian+of+London&rft.volume=18&rft.issue=214&rft.pages=237-256&rft.date=1694&rft_id=info%3Adoi%2F10.1098%2Frstl.1694.0048&rft_id=info%3Abibcode%2F1694RSPT...18..237C&rft.aulast=Halley&rft.aufirst=E.&rft_id=https%3A%2F%2Fdoi.org%2F10.1098%252Frstl.1694.0048&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFizeau1849" class="citation journal cs1 cs1-prop-foreign-lang-source"><a href="/wiki/Hippolyte_Fizeau" title="Hippolyte Fizeau">Fizeau, H. L.</a> (1849). <a rel="nofollow" class="external text" href="https://www.academie-sciences.fr/pdf/dossiers/Fizeau/Fizeau_pdf/CR1849_p90.pdf">"Sur une expérience relative à la vitesse de propagation de la lumière"</a> (PDF). <a href="/wiki/Comptes_rendus_de_l%27Acad%C3%A9mie_des_sciences" class="mw-redirect" title="Comptes rendus de l'Académie des sciences">Comptes rendus de l'Académie des sciences</a> (in French). 29: 90–92, 132.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Comptes+rendus+de+l%27Acad%C3%A9mie+des+sciences&rft.atitle=Sur+une+exp%C3%A9rience+relative+%C3%A0+la+vitesse+de+propagation+de+la+lumi%C3%A8re&rft.volume=29&rft.pages=90-92%2C+132&rft.date=1849&rft.aulast=Fizeau&rft.aufirst=H.+L.&rft_id=https%3A%2F%2Fwww.academie-sciences.fr%2Fpdf%2Fdossiers%2FFizeau%2FFizeau_pdf%2FCR1849_p90.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFoucault1862" class="citation journal cs1 cs1-prop-foreign-lang-source"><a href="/wiki/L%C3%A9on_Foucault" title="Léon Foucault">Foucault, J. L.</a> (1862). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=yYIIAAAAMAAJ&pg=PA216">"Détermination expérimentale de la vitesse de la lumière: parallaxe du Soleil"</a>. <a href="/wiki/Comptes_rendus_de_l%27Acad%C3%A9mie_des_sciences" class="mw-redirect" title="Comptes rendus de l'Académie des sciences">Comptes rendus de l'Académie des sciences</a> (in French). 55: 501–503, 792–796.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Comptes+rendus+de+l%27Acad%C3%A9mie+des+sciences&rft.atitle=D%C3%A9termination+exp%C3%A9rimentale+de+la+vitesse+de+la+lumi%C3%A8re%3A+parallaxe+du+Soleil&rft.volume=55&rft.pages=501-503%2C+792-796&rft.date=1862&rft.aulast=Foucault&rft.aufirst=J.+L.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DyYIIAAAAMAAJ%26pg%3DPA216&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichelson1878" class="citation journal cs1"><a href="/wiki/Albert_A._Michelson" title="Albert A. Michelson">Michelson, A. A.</a> (1878). <a rel="nofollow" class="external text" href="http://www.gutenberg.org/ebooks/11753">"Experimental Determination of the Velocity of Light"</a>. <a href="/wiki/Proceedings_of_the_American_Association_for_the_Advancement_of_Science" class="mw-redirect" title="Proceedings of the American Association for the Advancement of Science">Proceedings of the American Association for the Advancement of Science</a>. 27: 71–77.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+American+Association+for+the+Advancement+of+Science&rft.atitle=Experimental+Determination+of+the+Velocity+of+Light&rft.volume=27&rft.pages=71-77&rft.date=1878&rft.aulast=Michelson&rft.aufirst=A.+A.&rft_id=http%3A%2F%2Fwww.gutenberg.org%2Febooks%2F11753&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichelsonPeasePearson1935" class="citation journal cs1">Michelson, A. A.; <a href="/wiki/Francis_G._Pease" title="Francis G. Pease">Pease, F. G.</a>; Pearson, F. (1935). "Measurement of the Velocity of Light in a Partial Vacuum". <a href="/wiki/Astrophysical_Journal" class="mw-redirect" title="Astrophysical Journal">Astrophysical Journal</a>. 82 (2091): 26–61. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1935ApJ....82...26M">1935ApJ....82...26M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F143655">10.1086/143655</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17816642">17816642</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:123010613">123010613</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astrophysical+Journal&rft.atitle=Measurement+of+the+Velocity+of+Light+in+a+Partial+Vacuum&rft.volume=82&rft.issue=2091&rft.pages=26-61&rft.date=1935&rft_id=info%3Adoi%2F10.1086%2F143655&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A123010613%23id-name%3DS2CID&rft_id=info%3Apmid%2F17816642&rft_id=info%3Abibcode%2F1935ApJ....82...26M&rft.aulast=Michelson&rft.aufirst=A.+A.&rft.au=Pease%2C+F.+G.&rft.au=Pearson%2C+F.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNewcomb1886" class="citation journal cs1"><a href="/wiki/Simon_Newcomb" title="Simon Newcomb">Newcomb, S.</a> (1886). <a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F034029c0">"The Velocity of Light"</a>. <a href="/wiki/Nature_(journal)" title="Nature (journal)">Nature</a>. 34 (863): 29–32. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1886Natur..34...29.">1886Natur..34...29.</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F034029c0">10.1038/034029c0</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=The+Velocity+of+Light&rft.volume=34&rft.issue=863&rft.pages=29-32&rft.date=1886&rft_id=info%3Adoi%2F10.1038%2F034029c0&rft_id=info%3Abibcode%2F1886Natur..34...29.&rft.aulast=Newcomb&rft.aufirst=S.&rft_id=https%3A%2F%2Fdoi.org%2F10.1038%252F034029c0&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPerrotin1900" class="citation journal cs1 cs1-prop-foreign-lang-source"><a href="/wiki/Henri_Joseph_Anastase_Perrotin" title="Henri Joseph Anastase Perrotin">Perrotin, J.</a> (1900). "Sur la vitesse de la lumière". <a href="/wiki/Comptes_rendus_de_l%27Acad%C3%A9mie_des_sciences" class="mw-redirect" title="Comptes rendus de l'Académie des sciences">Comptes rendus de l'Académie des sciences</a> (in French). 131: 731–734.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Comptes+rendus+de+l%27Acad%C3%A9mie+des+sciences&rft.atitle=Sur+la+vitesse+de+la+lumi%C3%A8re&rft.volume=131&rft.pages=731-734&rft.date=1900&rft.aulast=Perrotin&rft.aufirst=J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </div> <div class="mw-heading mw-heading3"><h3 id="Modern_references">Modern references</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239549316"><div class="refbegin" style=""> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrillouin1960" class="citation book cs1"><a href="/wiki/L%C3%A9on_Brillouin" title="Léon Brillouin">Brillouin, L.</a> (1960). Wave propagation and group velocity. <a href="/wiki/Academic_Press" title="Academic Press">Academic Press</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Wave+propagation+and+group+velocity&rft.pub=Academic+Press&rft.date=1960&rft.aulast=Brillouin&rft.aufirst=L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJackson1975" class="citation book cs1"><a href="/wiki/John_David_Jackson_(physicist)" title="John David Jackson (physicist)">Jackson, J. D.</a> (1975). Classical Electrodynamics (2 ed.). John Wiley & Sons. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-471-30932-1" title="Special:BookSources/978-0-471-30932-1"><bdi>978-0-471-30932-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Classical+Electrodynamics&rft.edition=2&rft.pub=John+Wiley+%26+Sons&rft.date=1975&rft.isbn=978-0-471-30932-1&rft.aulast=Jackson&rft.aufirst=J.+D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKeiser2000" class="citation book cs1">Keiser, G. (2000). <a rel="nofollow" class="external text" href="https://archive.org/details/opticalfibercomm00gerd/page/32">Optical Fiber Communications</a> (3 ed.). McGraw-Hill. p. <a rel="nofollow" class="external text" href="https://archive.org/details/opticalfibercomm00gerd/page/32">32</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-07-232101-2" title="Special:BookSources/978-0-07-232101-2"><bdi>978-0-07-232101-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Optical+Fiber+Communications&rft.pages=32&rft.edition=3&rft.pub=McGraw-Hill&rft.date=2000&rft.isbn=978-0-07-232101-2&rft.aulast=Keiser&rft.aufirst=G.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fopticalfibercomm00gerd%2Fpage%2F32&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNg2004" class="citation book cs1">Ng, Y. J. (2004). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=RntpN7OesBsC">"Quantum Foam and Quantum Gravity Phenomenology"</a>. In Amelino-Camelia, G; Kowalski-Glikman, J (eds.). Planck Scale Effects in Astrophysics and Cosmology. Springer. pp. 321ff. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-25263-4" title="Special:BookSources/978-3-540-25263-4"><bdi>978-3-540-25263-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Quantum+Foam+and+Quantum+Gravity+Phenomenology&rft.btitle=Planck+Scale+Effects+in+Astrophysics+and+Cosmology&rft.pages=321ff&rft.pub=Springer&rft.date=2004&rft.isbn=978-3-540-25263-4&rft.aulast=Ng&rft.aufirst=Y.+J.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DRntpN7OesBsC&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHelmckeRiehle2001" class="citation book cs1">Helmcke, J.; Riehle, F. (2001). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=WE22Fez60EcC&pg=PA453">"Physics behind the definition of the meter"</a>. In Quinn, T. J.; Leschiutta, S.; Tavella, P. (eds.). Recent advances in metrology and fundamental constants. <a href="/wiki/IOS_Press" title="IOS Press">IOS Press</a>. p. 453. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-58603-167-1" title="Special:BookSources/978-1-58603-167-1"><bdi>978-1-58603-167-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Physics+behind+the+definition+of+the+meter&rft.btitle=Recent+advances+in+metrology+and+fundamental+constants&rft.pages=453&rft.pub=IOS+Press&rft.date=2001&rft.isbn=978-1-58603-167-1&rft.aulast=Helmcke&rft.aufirst=J.&rft.au=Riehle%2C+F.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DWE22Fez60EcC%26pg%3DPA453&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDuff2004" class="citation arxiv cs1"><a href="/wiki/Michael_James_Duff" class="mw-redirect" title="Michael James Duff">Duff, M. J.</a> (2004). "Comment on time-variation of fundamental constants". <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/hep-th/0208093">hep-th/0208093</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=preprint&rft.jtitle=arXiv&rft.atitle=Comment+on+time-variation+of+fundamental+constants&rft.date=2004&rft_id=info%3Aarxiv%2Fhep-th%2F0208093&rft.aulast=Duff&rft.aufirst=M.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ASpeed+of+light" class="Z3988"></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"> <div class="side-box-flex"> <div class="side-box-image"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/34px-Wikiquote-logo.svg.png" decoding="async" width="34" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/51px-Wikiquote-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/68px-Wikiquote-logo.svg.png 2x" data-file-width="300" data-file-height="355" /></div> <div class="side-box-text plainlist">Wikiquote has quotations related to <a href="https://en.wikiquote.org/wiki/Special:Search/Speed_of_light" class="extiw" title="q:Special:Search/Speed of light">Speed of light</a>.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="https://books.google.com/books?id=UigDAAAAMBAJ&dq=1930+plane+%22Popular&pg=PA17">"Test Light Speed in Mile Long Vacuum Tube"</a>. Popular Science Monthly, September 1930, pp. 17–18.</li> <li><a rel="nofollow" class="external text" href="http://www.bipm.org/en/si/si_brochure/chapter2/2-1/metre.html">Definition of the metre</a> (International Bureau of Weights and Measures, BIPM)</li> <li><a rel="nofollow" class="external text" href="http://physics.nist.gov/cgi-bin/cuu/Value?c">Speed of light in vacuum</a> (National Institute of Standards and Technology, NIST)</li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20040530221051/http://www.itl.nist.gov/div898/bayesian/datagall/michelso.htm">Data Gallery: Michelson Speed of Light (Univariate Location Estimation)</a> (download data gathered by <a href="/wiki/Albert_A._Michelson" title="Albert A. Michelson">Albert A. Michelson</a>)</li> <li><a rel="nofollow" class="external text" href="https://www.gregegan.net/APPLETS/20/20.html">Subluminal</a> (Java applet by <a href="/wiki/Greg_Egan" title="Greg Egan">Greg Egan</a> demonstrating group velocity information limits)</li> <li><a rel="nofollow" class="external text" href="http://www.ertin.com/sloan_on_speed_of_light.html">Light discussion on adding velocities</a></li> <li><a rel="nofollow" class="external text" href="http://sixtysymbols.com/videos/light.htm">Speed of Light</a> (Sixty Symbols, University of Nottingham Department of Physics [video])</li> <li><a rel="nofollow" class="external text" href="https://www.bbc.co.uk/programmes/p0038x9h">Speed of Light</a>, BBC Radio 4 discussion (In Our Time, 30 November 2006)</li> <li><a rel="nofollow" class="external text" href="http://www.live-counter.com/speed-of-light/">Speed of Light</a> (Live-Counter – Illustrations)</li> <li><a rel="nofollow" class="external text" href="https://www.sciencealert.com/simple-animations-by-a-nasa-scientist-prove-the-speed-of-light-is-torturously-slow">Speed of Light – animated demonstrations</a></li> <li>"<a rel="nofollow" class="external text" href="https://books.google.com/books?id=p4o9AQAAIAAJ">The Velocity of Light</a>", Albert A. Nicholson, <a href="/wiki/Scientific_American" title="Scientific American">Scientific American</a>, 28 September 1878, p. 193</li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Extremes_of_motion" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Extreme_motion" title="Template:Extreme motion"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Extreme_motion" title="Template talk:Extreme motion"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Extreme_motion" title="Special:EditPage/Template:Extreme motion"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Extremes_of_motion" style="font-size:114%;margin:0 4em">Extremes of motion</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Speed</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Wave <ul><li><a class="mw-selflink selflink">light</a></li> <li><a href="/wiki/Sound_barrier" title="Sound barrier">sound</a></li></ul></li> <li><a href="/wiki/List_of_vehicle_speed_records" title="List of vehicle speed records">Vehicle</a> <ul><li><a href="/wiki/List_of_vehicle_speed_records#Spacecraft" title="List of vehicle speed records">Spacecraft</a></li> <li><a href="/wiki/Flight_airspeed_record" title="Flight airspeed record">Aircraft</a> <ul><li><a href="/wiki/Fastest_propeller-driven_aircraft" title="Fastest propeller-driven aircraft">propeller-driven</a></li> <li><a href="/wiki/Transcontinental_flight" title="Transcontinental flight">transcontinental</a></li></ul></li> <li><a href="/wiki/Land_speed_record" title="Land speed record">Land vehicle</a> <ul><li><a href="/wiki/Land_speed_record" title="Land speed record">propulsively-driven</a></li> <li><a href="/wiki/Land_speed_racing#Records_by_class" title="Land speed racing">wheel-driven</a></li> <li><a href="/wiki/Railway_speed_record" title="Railway speed record">on rails</a></li> <li><a href="/wiki/Motorcycle_land-speed_record" title="Motorcycle land-speed record">motorcycle</a> <ul><li>production model <ul><li><a href="/wiki/List_of_fastest_production_motorcycles" title="List of fastest production motorcycles">by top speed</a></li> <li><a href="/wiki/List_of_fastest_production_motorcycles_by_acceleration" title="List of fastest production motorcycles by acceleration">by acceleration</a></li></ul></li></ul></li> <li>production car <ul><li><a href="/wiki/Production_car_speed_record" title="Production car speed record">by top speed</a></li> <li><a href="/wiki/List_of_fastest_production_cars_by_acceleration" title="List of fastest production cars by acceleration">by acceleration</a></li></ul></li> <li><a href="/wiki/British_land_speed_record" title="British land speed record">British</a></li></ul></li> <li><a href="/wiki/Water_speed_record" title="Water speed record">Water-borne vehicle</a> <ul><li><a href="/wiki/Speed_sailing_record" title="Speed sailing record">sailing</a></li> <li><a href="/wiki/Underwater_speed_record" title="Underwater speed record">submerged</a></li> <li><a href="/wiki/Blue_Riband" title="Blue Riband">transatlantic</a></li></ul></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Distance</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Space <ul><li><a href="/wiki/Voyager_1" title="Voyager 1">furthest spacecraft</a></li> <li><a href="/wiki/Huygens_(spacecraft)" title="Huygens (spacecraft)">furthest landing on another world</a></li> <li><a href="/wiki/Apollo_13" title="Apollo 13">furthest humans</a></li> <li><a href="/wiki/Opportunity_(rover)" title="Opportunity (rover)">furthest travel on another world</a></li> <li><a href="/wiki/Parker_Solar_Probe" title="Parker Solar Probe">closest to the Sun</a></li></ul></li> <li>Aircraft <ul><li><a href="/wiki/Flight_distance_record" title="Flight distance record">furthest flight</a></li> <li><a href="/wiki/Flight_altitude_record" title="Flight altitude record">highest altitude</a></li></ul></li> <li><a href="/wiki/Bathyscaphe_Trieste" class="mw-redirect" title="Bathyscaphe Trieste">Deepest ocean vehicle</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Endurance</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Space <ul><li><a href="/wiki/Voyager_2" title="Voyager 2">greatest of a spaceflight</a></li> <li><a href="/wiki/Opportunity_(rover)" title="Opportunity (rover)">greatest on another world</a></li> <li><a href="/wiki/Oleg_Kononenko" title="Oleg Kononenko">greatest of a person</a></li> <li><a href="/wiki/International_Space_Station" title="International Space Station">greatest of a spacecraft population</a></li></ul></li> <li><a href="/wiki/Flight_endurance_record" title="Flight endurance record">Aircraft</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">See also</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_spaceflight_records" title="List of spaceflight records">Spaceflight records</a></li> <li><a href="/wiki/F%C3%A9d%C3%A9ration_A%C3%A9ronautique_Internationale#Some_of_the_records" title="Fédération Aéronautique Internationale">Fédération Aéronautique Internationale records</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Gravitational-wave_astronomy" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Gravitational_waves" title="Template:Gravitational waves"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Gravitational_waves" title="Template talk:Gravitational waves"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Gravitational_waves" title="Special:EditPage/Template:Gravitational waves"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Gravitational-wave_astronomy" style="font-size:114%;margin:0 4em"><a href="/wiki/Gravitational-wave_astronomy" title="Gravitational-wave astronomy">Gravitational-wave astronomy</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><a href="/wiki/Gravitational_wave" title="Gravitational wave">Gravitational wave</a></li> <li><a href="/wiki/Gravitational-wave_observatory" title="Gravitational-wave observatory">Gravitational-wave observatory</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Gravitational-wave_observatory" title="Gravitational-wave observatory">Detectors</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Gravitational-wave_observatory#Weber_bars" title="Gravitational-wave observatory">Resonant mass antennas</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Active</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/w/index.php?title=NAUTILUS&action=edit&redlink=1" class="new" title="NAUTILUS (page does not exist)">NAUTILUS</a> (<a href="/w/index.php?title=International_Gravitational_Event_Collaboration&action=edit&redlink=1" class="new" title="International Gravitational Event Collaboration (page does not exist)">IGEC</a>)</li> <li><a href="/wiki/AURIGA" title="AURIGA">AURIGA</a> (<a href="/w/index.php?title=International_Gravitational_Event_Collaboration&action=edit&redlink=1" class="new" title="International Gravitational Event Collaboration (page does not exist)">IGEC</a>)</li> <li><a href="/wiki/MiniGrail" title="MiniGrail">MiniGRAIL</a></li> <li><a href="/wiki/Mario_Schenberg_(Gravitational_Wave_Detector)" title="Mario Schenberg (Gravitational Wave Detector)">Mario Schenberg</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Past</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/w/index.php?title=EXPLORER&action=edit&redlink=1" class="new" title="EXPLORER (page does not exist)">EXPLORER</a> (<a href="/w/index.php?title=International_Gravitational_Event_Collaboration&action=edit&redlink=1" class="new" title="International Gravitational Event Collaboration (page does not exist)">IGEC</a>)</li> <li><a href="/wiki/Allegro_gravitational-wave_detector" title="Allegro gravitational-wave detector">ALLEGRO</a> (<a href="/w/index.php?title=International_Gravitational_Event_Collaboration&action=edit&redlink=1" class="new" title="International Gravitational Event Collaboration (page does not exist)">IGEC</a>)</li> <li><a href="/wiki/NIOBE" title="NIOBE">NIOBE</a> (<a href="/w/index.php?title=International_Gravitational_Event_Collaboration&action=edit&redlink=1" class="new" title="International Gravitational Event Collaboration (page does not exist)">IGEC</a>)</li> <li><a href="/w/index.php?title=Stanford_gravitational_wave_detector&action=edit&redlink=1" class="new" title="Stanford gravitational wave detector (page does not exist)">Stanford gravitational wave detector</a></li> <li><a href="/w/index.php?title=ALTAIR_(gravitational_wave_detector)&action=edit&redlink=1" class="new" title="ALTAIR (gravitational wave detector) (page does not exist)">ALTAIR</a></li> <li><a href="/w/index.php?title=GEOGRAV&action=edit&redlink=1" class="new" title="GEOGRAV (page does not exist)">GEOGRAV</a></li> <li><a href="/w/index.php?title=AGATA_(gravitational_wave_detector)&action=edit&redlink=1" class="new" title="AGATA (gravitational wave detector) (page does not exist)">AGATA</a></li> <li><a href="/wiki/Weber_bar" title="Weber bar">Weber bar</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Proposed</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Torsion-bar_antenna" title="Torsion-bar antenna">TOBA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Past proposals</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/MiniGrail" title="MiniGrail">GRAIL</a> (downsized to <a href="/wiki/MiniGrail" title="MiniGrail">MiniGRAIL</a>)</li> <li><a href="/w/index.php?title=Truncated_Icosahedral_Gravitational_Wave_Antenna&action=edit&redlink=1" class="new" title="Truncated Icosahedral Gravitational Wave Antenna (page does not exist)">TIGA</a></li> <li><a href="/w/index.php?title=SFERA&action=edit&redlink=1" class="new" title="SFERA (page does not exist)">SFERA</a></li> <li><a href="/wiki/Mario_Schenberg_(Gravitational_Wave_Detector)" title="Mario Schenberg (Gravitational Wave Detector)">Graviton</a> (downsized to <a href="/wiki/Mario_Schenberg_(Gravitational_Wave_Detector)" title="Mario Schenberg (Gravitational Wave Detector)">Mario Schenberg</a>)</li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Ground-based_interferometric_gravitational-wave_search" title="Ground-based interferometric gravitational-wave search"> Ground-based interferometers</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Active</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/AIGO" title="AIGO">AIGO</a> (<a href="/wiki/ACIGA" title="ACIGA">ACIGA</a>)</li> <li><a href="/wiki/CLIO" title="CLIO">CLIO</a></li> <li><a href="/wiki/Holometer" title="Holometer">Fermilab holometer</a></li> <li><a href="/wiki/GEO600" title="GEO600">GEO600</a></li> <li><a href="/wiki/LIGO" title="LIGO">Advanced LIGO</a> (<a href="/wiki/LIGO_Scientific_Collaboration" title="LIGO Scientific Collaboration">LIGO Scientific Collaboration</a>)</li> <li><a href="/wiki/KAGRA" title="KAGRA">KAGRA</a></li> <li><a href="/wiki/Virgo_interferometer" title="Virgo interferometer">Advanced Virgo</a> (<a href="/wiki/European_Gravitational_Observatory" title="European Gravitational Observatory">European Gravitational Observatory</a>)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Past</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/TAMA_300" title="TAMA 300">TAMA 300</a></li> <li><a href="/wiki/TAMA_300" title="TAMA 300">TAMA 20, later known as LISM</a></li> <li><a href="/w/index.php?title=TENKO-100&action=edit&redlink=1" class="new" title="TENKO-100 (page does not exist)">TENKO-100</a></li> <li><a href="/wiki/LIGO#Background" title="LIGO">Caltech 40m interferometer</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Planned</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Indian_Initiative_in_Gravitational-wave_Observations" title="Indian Initiative in Gravitational-wave Observations">INDIGO (LIGO-India)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Proposed</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cosmic_Explorer_(gravitational_wave_observatory)" title="Cosmic Explorer (gravitational wave observatory)">Cosmic Explorer</a></li> <li><a href="/wiki/Einstein_Telescope" title="Einstein Telescope">Einstein Telescope</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Past proposals</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/LIGO-Australia" class="mw-redirect" title="LIGO-Australia">LIGO-Australia</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Space-based interferometers</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Planned</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Laser_Interferometer_Space_Antenna" title="Laser Interferometer Space Antenna">LISA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Proposed</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Big_Bang_Observer" title="Big Bang Observer">Big Bang Observer</a></li> <li><a href="/wiki/Deci-hertz_Interferometer_Gravitational_wave_Observatory" title="Deci-hertz Interferometer Gravitational wave Observatory">DECIGO</a></li> <li><a href="/wiki/TianQin" title="TianQin">TianQin</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Pulsar_timing_array" title="Pulsar timing array">Pulsar timing arrays</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/European_Pulsar_Timing_Array" title="European Pulsar Timing Array">EPTA</a></li> <li><a href="/wiki/International_Pulsar_Timing_Array" title="International Pulsar Timing Array">IPTA</a></li> <li><a href="/wiki/North_American_Nanohertz_Observatory_for_Gravitational_Waves" title="North American Nanohertz Observatory for Gravitational Waves">NANOGrav</a></li> <li><a href="/wiki/Parkes_Observatory" title="Parkes Observatory">PPTA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Data analysis</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Einstein@Home" title="Einstein@Home">Einstein@Home</a></li> <li><a href="/wiki/PyCBC" title="PyCBC">PyCBC</a></li> <li><a href="/wiki/Zooniverse" title="Zooniverse">Zooniverse</a>: Gravity Spy</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Observations</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Events</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_gravitational_wave_observations" title="List of gravitational wave observations">List of observations</a></li> <li><a href="/wiki/First_observation_of_gravitational_waves" title="First observation of gravitational waves">First observation (GW150914)</a></li> <li><a href="/wiki/GW151226" title="GW151226">GW151226</a></li> <li><a href="/wiki/GW170104" title="GW170104">GW170104</a></li> <li><a href="/wiki/GW170608" title="GW170608">GW170608</a></li> <li><a href="/wiki/GW170814" title="GW170814">GW170814</a></li> <li><a href="/wiki/GW170817" title="GW170817">GW170817</a> (first <a href="/wiki/Neutron_star_merger" title="Neutron star merger">neutron star merger</a>)</li> <li><a href="/wiki/GW190412" title="GW190412">GW190412</a></li> <li><a href="/wiki/GW190521" title="GW190521">GW190521</a> (first-ever possible light from bh-bh merger)</li> <li><a href="/wiki/GW190814" title="GW190814">GW190814</a> (first-ever "mass gap" collision)</li> <li><a href="/w/index.php?title=GW200105&action=edit&redlink=1" class="new" title="GW200105 (page does not exist)">GW200105</a> (first black hole - neutron star merger)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Methods</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Direct detection <ul><li><a href="/wiki/Interferometric_gravitational-wave_detector" class="mw-redirect" title="Interferometric gravitational-wave detector">Laser interferometers</a></li> <li>Resonant mass detectors</li> <li>Proposed: <a href="/wiki/Atom_interferometer" title="Atom interferometer">Atom interferometers</a></li></ul></li> <li>Indirect detection <ul><li><a href="/wiki/Cosmic_microwave_background#B-modes" title="Cosmic microwave background">B-modes</a> of <a href="/wiki/Cosmic_microwave_background" title="Cosmic microwave background">CMB</a></li> <li><a href="/wiki/Pulsar_timing_array" title="Pulsar timing array">Pulsar timing array</a></li> <li><a href="/wiki/Binary_pulsar" title="Binary pulsar">Binary pulsar</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Theory</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/General_relativity" title="General relativity">General relativity</a></li> <li><a href="/wiki/Tests_of_general_relativity" title="Tests of general relativity">Tests of general relativity</a></li> <li><a href="/wiki/Alternatives_to_general_relativity" title="Alternatives to general relativity">Metric theories</a></li> <li><a href="/wiki/Graviton" title="Graviton">Graviton</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Effects / properties</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Gravitational_wave#Effects_of_passing" title="Gravitational wave">Polarization</a></li> <li><a href="/wiki/Spin-flip" title="Spin-flip">Spin-flip</a></li> <li><a href="/wiki/Redshift" title="Redshift">Redshift</a></li> <li>Travel with <a class="mw-selflink selflink">speed of light</a></li> <li>h strain</li> <li>Chirp signal (<a href="/wiki/Chirp_mass" title="Chirp mass">chirp mass</a>)</li> <li>Carried <a href="/wiki/Energy" title="Energy">energy</a></li> <li><a href="/wiki/Gravitational_wave_background" title="Gravitational wave background">Gravitational wave background</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Types / sources</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Stochastic" title="Stochastic">Stochastic</a> <ul><li><a href="/wiki/Cosmic_inflation" title="Cosmic inflation">Cosmic inflation</a>-<a href="/wiki/Quantum_fluctuation" title="Quantum fluctuation">quantum fluctuation</a></li> <li><a href="/wiki/Phase_transition" title="Phase transition">Phase transition</a></li></ul></li> <li>Binary inspiral <ul><li><a href="/wiki/Supermassive_black_hole" title="Supermassive black hole">Supermassive black holes</a></li> <li><a href="/wiki/Stellar_black_hole" title="Stellar black hole">Stellar black holes</a></li> <li><a href="/wiki/Neutron_star" title="Neutron star">Neutron stars</a></li> <li><a href="/wiki/Extreme_mass_ratio_inspiral" title="Extreme mass ratio inspiral">EMRI</a></li></ul></li> <li>Continuous <ul><li>Rotating neutron star</li></ul></li> <li>Burst <ul><li><a href="/wiki/Supernova" title="Supernova">Supernova</a> or from unknown sources</li></ul></li> <li>Hypothesis <ul><li>Colliding <a href="/wiki/Cosmic_string" title="Cosmic string">cosmic string</a> and other unknown sources</li></ul></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Records" style="padding:3px"><table class="nowraplinks mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Records" title="Template:Records"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Records" title="Template talk:Records"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Records" title="Special:EditPage/Template:Records"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Records" style="font-size:114%;margin:0 4em"><a href="/wiki/World_record" title="World record">Records</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/World_record" title="World record">World records</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Category:World_records" title="Category:World records">Category: World records</a></li> <li><a href="/wiki/Guinness_World_Records" title="Guinness World Records">Guinness World Records</a></li> <li><a href="/wiki/Limca_Book_of_Records" title="Limca Book of Records">Limca Book of Records</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">People</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_heaviest_people" title="List of heaviest people">Heaviest</a></li> <li><a href="/wiki/Oldest_people" title="Oldest people">Oldest</a></li> <li><a href="/wiki/List_of_the_verified_shortest_people" title="List of the verified shortest people">Shortest</a></li> <li><a href="/wiki/List_of_tallest_people" title="List of tallest people">Tallest</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Sporting records</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_world_records_in_chess" title="List of world records in chess">Chess</a></li> <li><a href="/wiki/List_of_first-class_cricket_records" title="List of first-class cricket records">Cricket</a> <ul><li><a href="/wiki/List_of_Test_cricket_records" title="List of Test cricket records">Test</a></li> <li><a href="/wiki/List_of_One_Day_International_cricket_records" title="List of One Day International cricket records">One Day International</a></li> <li><a href="/wiki/List_of_Twenty20_International_records" title="List of Twenty20 International records">Twenty20 International</a></li></ul></li> <li><a href="/wiki/List_of_cycling_records" title="List of cycling records">Cycling</a></li> <li><a href="/wiki/FIBA_Basketball_World_Cup_records" title="FIBA Basketball World Cup records">FIBA Basketball World Cup records</a></li> <li><a href="/wiki/List_of_FIFA_World_Cup_records_and_statistics" class="mw-redirect" title="List of FIFA World Cup records and statistics">FIFA World Cup records</a></li> <li>Formula One motorsport <ul><li><a href="/wiki/List_of_Formula_One_constructor_records" title="List of Formula One constructor records">constructors</a></li> <li><a href="/wiki/List_of_Formula_One_driver_records" title="List of Formula One driver records">drivers</a></li></ul></li> <li><a href="/wiki/List_of_Grand_Prix_motorcycle_racing_rider_records" title="List of Grand Prix motorcycle racing rider records">Grand Prix motorcycle racing</a></li> <li><a href="/wiki/Juggling_world_records" title="Juggling world records">Juggling</a></li> <li><a href="/wiki/List_of_World_Rally_Championship_records" title="List of World Rally Championship records">World Rally Championship</a></li> <li><a href="/wiki/List_of_world_records_in_speed_skating" title="List of world records in speed skating">Speed skating</a></li> <li><a href="/wiki/ISU_Judging_System#World_records" title="ISU Judging System">Figure skating</a></li> <li><a href="/wiki/List_of_world_records_in_swimming" title="List of world records in swimming">Swimming</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_world_records_in_athletics" title="List of world records in athletics">Athletics</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Athletics_record_progressions" class="mw-redirect" title="Athletics record progressions">Athletics record progressions</a></li> <li><a href="/wiki/List_of_Olympic_records_in_athletics" title="List of Olympic records in athletics">Olympic records</a></li> <li><a href="/wiki/National_records_in_athletics" title="National records in athletics">National records</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_world_records_in_Olympic_weightlifting" title="List of world records in Olympic weightlifting">Weightlifting</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/World_record_progression_men%27s_weightlifting" title="World record progression men's weightlifting">Men</a> <ul><li><a href="/wiki/World_record_progression_men%27s_weightlifting_(1993%E2%80%931997)" title="World record progression men's weightlifting (1993–1997)">1993–1997</a></li> <li><a href="/wiki/World_record_progression_men%27s_weightlifting_(1998%E2%80%932018)" title="World record progression men's weightlifting (1998–2018)">1998–2018</a></li></ul></li> <li><a href="/wiki/World_record_progression_women%27s_weightlifting" title="World record progression women's weightlifting">Women</a> <ul><li><a href="/wiki/World_record_progression_women%27s_weightlifting_(1998%E2%80%932018)" title="World record progression women's weightlifting (1998–2018)">1998–2018</a></li></ul></li> <li><a href="/wiki/List_of_junior_world_records_in_Olympic_weightlifting" title="List of junior world records in Olympic weightlifting">Junior</a></li> <li><a href="/wiki/List_of_youth_world_records_in_Olympic_weightlifting" title="List of youth world records in Olympic weightlifting">Youth</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">In Australia</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_National_Rugby_League_records" title="List of National Rugby League records">National Rugby League</a></li> <li><a href="/wiki/List_of_VFL/AFL_records" title="List of VFL/AFL records">Australian Football League</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">In the US</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>NBA <ul><li><a href="/wiki/NBA_regular_season_records" class="mw-redirect" title="NBA regular season records">Regular season</a></li> <li><a href="/wiki/NBA_post-season_records" class="mw-redirect" title="NBA post-season records">Post-season</a></li> <li><a href="/wiki/List_of_NBA_All-Star_Game_records" title="List of NBA All-Star Game records">All-Star</a></li></ul></li> <li>NFL <ul><li><a href="/wiki/List_of_National_Football_League_records_(individual)" class="mw-redirect" title="List of National Football League records (individual)">Individual</a></li> <li><a href="/wiki/List_of_National_Football_League_records_(team)" class="mw-redirect" title="List of National Football League records (team)">Team</a></li></ul></li> <li>NHL <ul><li><a href="/wiki/List_of_NHL_records_(individual)" title="List of NHL records (individual)">Individual</a></li> <li><a href="/wiki/List_of_NHL_records_(team)" title="List of NHL records (team)">Team</a></li> <li><a href="/wiki/List_of_NHL_All-Star_Game_records" title="List of NHL All-Star Game records">All-Star</a></li></ul></li> <li><a href="/wiki/List_of_Major_League_Baseball_records_considered_unbreakable" title="List of Major League Baseball records considered unbreakable">Major League Baseball</a> <ul><li><a href="/wiki/List_of_Major_League_Baseball_career_records" title="List of Major League Baseball career records">Career</a></li> <li><a href="/wiki/List_of_Major_League_Baseball_single-season_records" title="List of Major League Baseball single-season records">Season</a></li> <li><a href="/wiki/List_of_Major_League_Baseball_single-game_records" title="List of Major League Baseball single-game records">Game</a></li></ul></li> <li><a href="/wiki/Major_League_Soccer_records_and_statistics" title="Major League Soccer records and statistics">Major League Soccer</a></li> <li><a href="/wiki/List_of_United_States_records_in_track_and_field" title="List of United States records in track and field">Track and field</a></li> <li>WNBA <ul><li><a href="/wiki/List_of_WNBA_regular_season_records" title="List of WNBA regular season records">Regular season</a></li> <li><a href="/wiki/List_of_WNBA_post-season_records" title="List of WNBA post-season records">Post-season</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">In India</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_Indian_Super_League_records_and_statistics" class="mw-redirect" title="List of Indian Super League records and statistics">Indian Super League</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">National records</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_records_of_Japan" title="List of records of Japan">Japan</a></li> <li><a href="/wiki/List_of_Palestinian_records" title="List of Palestinian records">Palestine</a></li> <li><a href="/wiki/List_of_records_of_the_Philippines" title="List of records of the Philippines">Philippines</a></li> <li><a href="/wiki/List_of_records_of_Thailand" title="List of records of Thailand">Thailand</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Motion records</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Speed</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Wave <ul><li><a class="mw-selflink selflink">Light</a></li> <li><a href="/wiki/Sound_barrier" title="Sound barrier">Sound</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_vehicle_speed_records" title="List of vehicle speed records">Vehicle</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_vehicle_speed_records#Spacecraft" title="List of vehicle speed records">Spacecraft</a></li> <li><a href="/wiki/Flight_airspeed_record" title="Flight airspeed record">Aircraft</a> <ul><li><a href="/wiki/Fastest_propeller-driven_aircraft" title="Fastest propeller-driven aircraft">Propeller-driven</a></li> <li><a href="/wiki/Transcontinental_flight" title="Transcontinental flight">Transcontinental</a></li></ul></li> <li><a href="/wiki/Land_speed_record" title="Land speed record">Land vehicle (propulsively-driven</a></li> <li><a href="/wiki/Land_speed_racing#Records_by_class" title="Land speed racing">Wheel-driven</a></li> <li><a href="/wiki/Railway_speed_record" title="Railway speed record">On rails</a></li> <li><a href="/wiki/Motorcycle_land-speed_record" title="Motorcycle land-speed record">Motorcycle</a> <ul><li>Production model <ul><li><a href="/wiki/List_of_fastest_production_motorcycles" title="List of fastest production motorcycles">by top speed</a></li> <li><a href="/wiki/List_of_fastest_production_motorcycles_by_acceleration" title="List of fastest production motorcycles by acceleration">by acceleration</a></li></ul></li></ul></li> <li>Production car <ul><li><a href="/wiki/Production_car_speed_record" title="Production car speed record">by top speed</a></li> <li><a href="/wiki/List_of_fastest_production_cars_by_acceleration" title="List of fastest production cars by acceleration">by acceleration</a></li> <li><a href="/wiki/List_of_production_cars_by_power_output" title="List of production cars by power output">Power output</a></li></ul></li> <li><a href="/wiki/British_land_speed_record" title="British land speed record">British</a></li> <li><a href="/wiki/Water_speed_record" title="Water speed record">Water-borne vehicle</a> <ul><li><a href="/wiki/Speed_sailing_record" title="Speed sailing record">Sailing</a></li> <li><a href="/wiki/Underwater_speed_record" title="Underwater speed record">Submerged</a></li> <li><a href="/wiki/Blue_Riband" title="Blue Riband">Transatlantic</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Distance</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Voyager_1" title="Voyager 1">Furthest spacecraft</a></li> <li><a href="/wiki/Huygens_(spacecraft)" title="Huygens (spacecraft)">Furthest landing on another world</a></li> <li><a href="/wiki/Apollo_13" title="Apollo 13">Furthest humans</a></li> <li><a href="/wiki/Opportunity_(rover)" title="Opportunity (rover)">Furthest travel on another world</a></li> <li><a href="/wiki/Parker_Solar_Probe" title="Parker Solar Probe">Closest to the Sun)</a></li> <li><a href="/wiki/Flight_distance_record" title="Flight distance record">Furthest flight</a></li> <li><a href="/wiki/Flight_altitude_record" title="Flight altitude record">Highest altitude)</a></li> <li><a href="/wiki/Bathyscaphe_Trieste" class="mw-redirect" title="Bathyscaphe Trieste">Deepest ocean vehicle</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Endurance</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li>Space <ul><li><a href="/wiki/Voyager_2" title="Voyager 2">Spaceflight</a></li> <li><a href="/wiki/Opportunity_(rover)" title="Opportunity (rover)">On another world</a></li> <li><a href="/wiki/Oleg_Kononenko" title="Oleg Kononenko">Person</a></li> <li><a href="/wiki/International_Space_Station" title="International Space Station">Spacecraft population</a></li></ul></li> <li><a href="/wiki/Flight_endurance_record" title="Flight endurance record">Aircraft</a></li></ul> </div></td></tr><tr><td colspan="2" class="navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_spaceflight_records" title="List of spaceflight records">Spaceflight records</a></li> <li><a href="/wiki/F%C3%A9d%C3%A9ration_A%C3%A9ronautique_Internationale#Some_of_the_records" title="Fédération Aéronautique Internationale">Fédération Aéronautique Internationale records</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Structures</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_tallest_buildings_and_structures" title="List of tallest buildings and structures">Tallest structures</a></li> <li><a href="/wiki/Category:Lists_of_tallest_structures" title="Category:Lists of tallest structures">Category on tallest structures</a></li> <li><a href="/wiki/List_of_superlative_trees" title="List of superlative trees">Superlative trees</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Physical phenomena</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_Solar_System_extremes" title="List of Solar System extremes">Solar System extremes</a> <ul><li><a href="/wiki/Extremes_on_Earth" title="Extremes on Earth">Extremes on Earth</a> <ul><li><a href="/wiki/Extreme_points_of_Earth" class="mw-redirect" title="Extreme points of Earth">Extreme points of Earth</a></li> <li><a href="/wiki/List_of_weather_records" title="List of weather records">List of weather records</a></li></ul></li></ul></li> <li>Organisms <ul><li><a href="/wiki/List_of_longest-living_organisms" title="List of longest-living organisms">List of longest-living organisms</a></li> <li><a href="/wiki/Smallest_organisms" title="Smallest organisms">Smallest organisms</a></li> <li><a href="/wiki/Largest_organisms" title="Largest organisms">Largest organisms</a></li></ul></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Relativity" style="padding:3px"><table class="nowraplinks mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2" style="text-align:center;"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Relativity" title="Template:Relativity"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Relativity" title="Template talk:Relativity"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Relativity" title="Special:EditPage/Template:Relativity"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Relativity" style="font-size:114%;margin:0 4em"><a href="/wiki/Theory_of_relativity" title="Theory of relativity">Relativity</a></div></th></tr><tr><th scope="row" class="navbox-group" style="text-align:center;;width:1%"><a href="/wiki/Special_relativity" title="Special relativity">Special relativity</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Background</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Principle_of_relativity" title="Principle of relativity">Principle of relativity</a> (<a href="/wiki/Galilean_invariance" title="Galilean invariance">Galilean relativity</a></li> <li><a href="/wiki/Galilean_transformation" title="Galilean transformation">Galilean transformation</a>)</li> <li><a href="/wiki/Special_relativity" title="Special relativity">Special relativity</a></li> <li><a href="/wiki/Doubly_special_relativity" title="Doubly special relativity">Doubly special relativity</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Fundamental concepts</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Frame_of_reference" title="Frame of reference">Frame of reference</a></li> <li><a class="mw-selflink selflink">Speed of light</a></li> <li><a href="/wiki/Hyperbolic_orthogonality" title="Hyperbolic orthogonality">Hyperbolic orthogonality</a></li> <li><a href="/wiki/Rapidity" title="Rapidity">Rapidity</a></li> <li><a href="/wiki/Maxwell%27s_equations" title="Maxwell's equations">Maxwell's equations</a></li> <li><a href="/wiki/Proper_length" title="Proper length">Proper length</a></li> <li><a href="/wiki/Proper_time" title="Proper time">Proper time</a></li> <li><a href="/wiki/Proper_acceleration" title="Proper acceleration">Proper acceleration</a></li> <li><a href="/wiki/Mass_in_special_relativity" title="Mass in special relativity">Relativistic mass</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Formulation</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Lorentz_transformation" title="Lorentz transformation">Lorentz transformation</a></li> <li><a href="/wiki/List_of_textbooks_on_relativity" title="List of textbooks on relativity">Textbooks</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Phenomena</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Time_dilation" title="Time dilation">Time dilation</a></li> <li><a href="/wiki/Mass%E2%80%93energy_equivalence" title="Mass–energy equivalence">Mass–energy equivalence (E=mc2)</a></li> <li><a href="/wiki/Length_contraction" title="Length contraction">Length contraction</a></li> <li><a href="/wiki/Relativity_of_simultaneity" title="Relativity of simultaneity">Relativity of simultaneity</a></li> <li><a href="/wiki/Relativistic_Doppler_effect" title="Relativistic Doppler effect">Relativistic Doppler effect</a></li> <li><a href="/wiki/Thomas_precession" title="Thomas precession">Thomas precession</a></li> <li><a href="/wiki/Ladder_paradox" title="Ladder paradox">Ladder paradox</a></li> <li><a href="/wiki/Twin_paradox" title="Twin paradox">Twin paradox</a></li> <li><a href="/wiki/Terrell_rotation" title="Terrell rotation">Terrell rotation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;"><a href="/wiki/Spacetime" title="Spacetime">Spacetime</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Light_cone" title="Light cone">Light cone</a></li> <li><a href="/wiki/World_line" title="World line">World line</a></li> <li><a href="/wiki/Minkowski_diagram" class="mw-redirect" title="Minkowski diagram">Minkowski diagram</a></li> <li><a href="/wiki/Biquaternion" title="Biquaternion">Biquaternions</a></li> <li><a href="/wiki/Minkowski_space" title="Minkowski space">Minkowski space</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="text-align:center;;width:1%"><a href="/wiki/General_relativity" title="General relativity">General relativity</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Background</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Introduction_to_general_relativity" title="Introduction to general relativity">Introduction</a></li> <li><a href="/wiki/Mathematics_of_general_relativity" title="Mathematics of general relativity">Mathematical formulation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Fundamental concepts</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Equivalence_principle" title="Equivalence principle">Equivalence principle</a></li> <li><a href="/wiki/Riemannian_geometry" title="Riemannian geometry">Riemannian geometry</a></li> <li><a href="/wiki/Penrose_diagram" title="Penrose diagram">Penrose diagram</a></li> <li><a href="/wiki/Geodesics_in_general_relativity" title="Geodesics in general relativity">Geodesics</a></li> <li><a href="/wiki/Mach%27s_principle" title="Mach's principle">Mach's principle</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Formulation</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ADM_formalism" title="ADM formalism">ADM formalism</a></li> <li><a href="/wiki/BSSN_formalism" title="BSSN formalism">BSSN formalism</a></li> <li><a href="/wiki/Einstein_field_equations" title="Einstein field equations">Einstein field equations</a></li> <li><a href="/wiki/Linearized_gravity" title="Linearized gravity">Linearized gravity</a></li> <li><a href="/wiki/Parameterized_post-Newtonian_formalism" title="Parameterized post-Newtonian formalism">Post-Newtonian formalism</a></li> <li><a href="/wiki/Raychaudhuri_equation" title="Raychaudhuri equation">Raychaudhuri equation</a></li> <li><a href="/wiki/Hamilton%E2%80%93Jacobi%E2%80%93Einstein_equation" title="Hamilton–Jacobi–Einstein equation">Hamilton–Jacobi–Einstein equation</a></li> <li><a href="/wiki/Ernst_equation" title="Ernst equation">Ernst equation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Phenomena</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Black_hole" title="Black hole">Black hole</a></li> <li><a href="/wiki/Event_horizon" title="Event horizon">Event horizon</a></li> <li><a href="/wiki/Gravitational_singularity" title="Gravitational singularity">Singularity</a></li> <li><a href="/wiki/Two-body_problem_in_general_relativity" title="Two-body problem in general relativity">Two-body problem</a></li></ul> <ul><li><a href="/wiki/Gravitational_wave" title="Gravitational wave">Gravitational waves</a>: <a href="/wiki/Gravitational-wave_astronomy" title="Gravitational-wave astronomy">astronomy</a></li> <li><a href="/wiki/Gravitational-wave_observatory" title="Gravitational-wave observatory">detectors</a> (<a href="/wiki/LIGO" title="LIGO">LIGO</a> and <a href="/wiki/LIGO_Scientific_Collaboration" title="LIGO Scientific Collaboration">collaboration</a></li> <li><a href="/wiki/Virgo_interferometer" title="Virgo interferometer">Virgo</a></li> <li><a href="/wiki/LISA_Pathfinder" title="LISA Pathfinder">LISA Pathfinder</a></li> <li><a href="/wiki/GEO600" title="GEO600">GEO</a>)</li> <li><a href="/wiki/Hulse%E2%80%93Taylor_binary" class="mw-redirect" title="Hulse–Taylor binary">Hulse–Taylor binary</a></li></ul> <ul><li><a href="/wiki/Tests_of_general_relativity" title="Tests of general relativity">Other tests</a>: <a href="/wiki/Apsidal_precession" title="Apsidal precession">precession</a> of Mercury</li> <li><a href="/wiki/Gravitational_lens" title="Gravitational lens">lensing</a> (together with <a href="/wiki/Einstein_cross" class="mw-redirect" title="Einstein cross">Einstein cross</a> and <a href="/wiki/Einstein_rings" class="mw-redirect" title="Einstein rings">Einstein rings</a>)</li> <li><a href="/wiki/Gravitational_redshift" title="Gravitational redshift">redshift</a></li> <li><a href="/wiki/Shapiro_time_delay" title="Shapiro time delay">Shapiro delay</a></li> <li><a href="/wiki/Frame-dragging" title="Frame-dragging">frame-dragging</a> / <a href="/wiki/Geodetic_effect" title="Geodetic effect">geodetic effect</a> (<a href="/wiki/Lense%E2%80%93Thirring_precession" title="Lense–Thirring precession">Lense–Thirring precession</a>)</li> <li><a href="/wiki/Pulsar_timing_array" title="Pulsar timing array">pulsar timing arrays</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;">Advanced theories</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Brans%E2%80%93Dicke_theory" title="Brans–Dicke theory">Brans–Dicke theory</a></li> <li><a href="/wiki/Kaluza%E2%80%93Klein_theory" title="Kaluza–Klein theory">Kaluza–Klein</a></li> <li><a href="/wiki/Quantum_gravity" title="Quantum gravity">Quantum gravity</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:6em;text-align:center;"><a href="/wiki/Exact_solutions_in_general_relativity" title="Exact solutions in general relativity">Solutions</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li>Cosmological: <a href="/wiki/Friedmann%E2%80%93Lema%C3%AEtre%E2%80%93Robertson%E2%80%93Walker_metric" title="Friedmann–Lemaître–Robertson–Walker metric">Friedmann–Lemaître–Robertson–Walker</a> (<a href="/wiki/Friedmann_equations" title="Friedmann equations">Friedmann equations</a>)</li> <li><a href="/wiki/Lema%C3%AEtre%E2%80%93Tolman_metric" title="Lemaître–Tolman metric">Lemaître–Tolman</a></li> <li><a href="/wiki/Kasner_metric" title="Kasner metric">Kasner</a></li> <li><a href="/wiki/BKL_singularity" title="BKL singularity">BKL singularity</a></li> <li><a href="/wiki/G%C3%B6del_metric" title="Gödel metric">Gödel</a></li> <li><a href="/wiki/Milne_model" title="Milne model">Milne</a></li></ul> <ul><li>Spherical: <a href="/wiki/Schwarzschild_metric" title="Schwarzschild metric">Schwarzschild</a> (<a href="/wiki/Interior_Schwarzschild_metric" title="Interior Schwarzschild metric">interior</a></li> <li><a href="/wiki/Tolman%E2%80%93Oppenheimer%E2%80%93Volkoff_equation" title="Tolman–Oppenheimer–Volkoff equation">Tolman–Oppenheimer–Volkoff equation</a>)</li> <li><a href="/wiki/Reissner%E2%80%93Nordstr%C3%B6m_metric" title="Reissner–Nordström metric">Reissner–Nordström</a></li></ul> <ul><li>Axisymmetric: <a href="/wiki/Kerr_metric" title="Kerr metric">Kerr</a> (<a href="/wiki/Kerr%E2%80%93Newman_metric" title="Kerr–Newman metric">Kerr–Newman</a>)</li> <li><a href="/wiki/Weyl%E2%88%92Lewis%E2%88%92Papapetrou_coordinates" class="mw-redirect" title="Weyl−Lewis−Papapetrou coordinates">Weyl−Lewis−Papapetrou</a></li> <li><a href="/wiki/Taub%E2%80%93NUT_space" title="Taub–NUT space">Taub–NUT</a></li> <li><a href="/wiki/Van_Stockum_dust" title="Van Stockum dust">van Stockum dust</a></li> <li><a href="/wiki/Relativistic_disk" title="Relativistic disk">discs</a></li></ul> <ul><li>Others: <a href="/wiki/Pp-wave_spacetime" title="Pp-wave spacetime">pp-wave</a></li> <li><a href="/wiki/Ozsv%C3%A1th%E2%80%93Sch%C3%BCcking_metric" title="Ozsváth–Schücking metric">Ozsváth–Schücking</a></li> <li><a href="/wiki/Alcubierre_drive" title="Alcubierre drive">Alcubierre</a></li></ul> <ul><li>In computational physics: <a href="/wiki/Numerical_relativity" title="Numerical relativity">Numerical relativity</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="text-align:center;;width:1%">Scientists</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Henri_Poincar%C3%A9" title="Henri Poincaré">Poincaré</a></li> <li><a href="/wiki/Hendrik_Lorentz" title="Hendrik Lorentz">Lorentz</a></li> <li><a href="/wiki/Albert_Einstein" title="Albert Einstein">Einstein</a></li> <li><a href="/wiki/David_Hilbert" title="David Hilbert">Hilbert</a></li> <li><a href="/wiki/Karl_Schwarzschild" title="Karl Schwarzschild">Schwarzschild</a></li> <li><a href="/wiki/Willem_de_Sitter" title="Willem de Sitter">de Sitter</a></li> <li><a href="/wiki/Hermann_Weyl" title="Hermann Weyl">Weyl</a></li> <li><a href="/wiki/Arthur_Eddington" title="Arthur Eddington">Eddington</a></li> <li><a href="/wiki/Alexander_Friedmann" title="Alexander Friedmann">Friedmann</a></li> <li><a href="/wiki/Georges_Lema%C3%AEtre" title="Georges Lemaître">Lemaître</a></li> <li><a href="/wiki/Edward_Arthur_Milne" title="Edward Arthur Milne">Milne</a></li> <li><a href="/wiki/Howard_P._Robertson" title="Howard P. Robertson">Robertson</a></li> <li><a href="/wiki/Subrahmanyan_Chandrasekhar" title="Subrahmanyan Chandrasekhar">Chandrasekhar</a></li> <li><a href="/wiki/Fritz_Zwicky" title="Fritz Zwicky">Zwicky</a></li> <li><a href="/wiki/John_Archibald_Wheeler" title="John Archibald Wheeler">Wheeler</a></li> <li><a href="/wiki/Yvonne_Choquet-Bruhat" title="Yvonne Choquet-Bruhat">Choquet-Bruhat</a></li> <li><a href="/wiki/Roy_Kerr" title="Roy Kerr">Kerr</a></li> <li><a href="/wiki/Yakov_Zeldovich" title="Yakov Zeldovich">Zel'dovich</a></li> <li><a href="/wiki/Igor_Dmitriyevich_Novikov" title="Igor Dmitriyevich Novikov">Novikov</a></li> <li><a href="/wiki/J%C3%BCrgen_Ehlers" title="Jürgen Ehlers">Ehlers</a></li> <li><a href="/wiki/Robert_Geroch" title="Robert Geroch">Geroch</a></li> <li><a href="/wiki/Roger_Penrose" title="Roger Penrose">Penrose</a></li> <li><a href="/wiki/Stephen_Hawking" title="Stephen Hawking">Hawking</a></li> <li><a href="/wiki/Joseph_Hooton_Taylor_Jr." title="Joseph Hooton Taylor Jr.">Taylor</a></li> <li><a href="/wiki/Russell_Alan_Hulse" title="Russell Alan Hulse">Hulse</a></li> <li><a href="/wiki/Hermann_Bondi" title="Hermann Bondi">Bondi</a></li> <li><a href="/wiki/Charles_W._Misner" title="Charles W. Misner">Misner</a></li> <li><a href="/wiki/Shing-Tung_Yau" title="Shing-Tung Yau">Yau</a></li> <li><a href="/wiki/Kip_Thorne" title="Kip Thorne">Thorne</a></li> <li><a href="/wiki/Rainer_Weiss" title="Rainer Weiss">Weiss</a></li> <li><a href="/wiki/List_of_contributors_to_general_relativity" title="List of contributors to general relativity">others</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2" style="text-align:center;"><div><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <a href="/wiki/Category:Theory_of_relativity" title="Category:Theory of relativity">Category</a></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"></div><div role="navigation" class="navbox" aria-labelledby="Special_relativity" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Special_relativity" title="Template:Special relativity"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Special_relativity" class="mw-redirect" title="Template talk:Special relativity"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Special_relativity" title="Special:EditPage/Template:Special relativity"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Special_relativity" style="font-size:114%;margin:0 4em"><a href="/wiki/Special_relativity" title="Special relativity">Special relativity</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Overviews</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Principle_of_relativity" title="Principle of relativity">Principle of relativity</a></li> <li><a href="/wiki/Theory_of_relativity" title="Theory of relativity">Theory of relativity</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div class="hlist"><ul><li><a href="/wiki/History_of_special_relativity" title="History of special relativity">History</a></li></ul></div></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Galilean_invariance" title="Galilean invariance">Galilean relativity</a></li> <li><a href="/wiki/Galilean_transformation" title="Galilean transformation">Galilean transformation</a></li> <li><a href="/wiki/Aether_theories" title="Aether theories">Aether theories</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Foundations</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Kinematics" title="Kinematics">Relative motion</a></li> <li><a href="/wiki/Inertial_frame_of_reference" title="Inertial frame of reference">Inertial frame of reference</a></li> <li><a class="mw-selflink selflink">Speed of light</a></li> <li><a href="/wiki/Maxwell%27s_equations" title="Maxwell's equations">Maxwell's equations</a></li> <li><a href="/wiki/Lorentz_transformation" title="Lorentz transformation">Lorentz transformation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Consequences</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Time_dilation" title="Time dilation">Time dilation</a></li> <li><a href="/wiki/Mass_in_special_relativity" title="Mass in special relativity">Relativistic mass</a></li> <li><a href="/wiki/Mass%E2%80%93energy_equivalence" title="Mass–energy equivalence">Mass–energy equivalence</a></li> <li><a href="/wiki/Length_contraction" title="Length contraction">Length contraction</a></li> <li><a href="/wiki/Relativity_of_simultaneity" title="Relativity of simultaneity">Relativity of simultaneity</a></li> <li><a href="/wiki/Relativistic_Doppler_effect" title="Relativistic Doppler effect">Relativistic Doppler effect</a></li> <li><a href="/wiki/Thomas_precession" title="Thomas precession">Thomas precession</a></li> <li><a href="/wiki/Relativistic_disk" title="Relativistic disk">Relativistic disk</a></li> <li><a href="/wiki/Bell%27s_spaceship_paradox" title="Bell's spaceship paradox">Bell's spaceship paradox</a></li> <li><a href="/wiki/Ehrenfest_paradox" title="Ehrenfest paradox">Ehrenfest paradox</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Spacetime" title="Spacetime">Spacetime</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Minkowski_space" title="Minkowski space">Minkowski spacetime</a></li> <li><a href="/wiki/World_line" title="World line">World line</a></li> <li><a href="/wiki/Minkowski_diagram" class="mw-redirect" title="Minkowski diagram">Spacetime diagrams</a></li> <li><a href="/wiki/Light_cone" title="Light cone">Light cone</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Dynamics_(mechanics)" class="mw-redirect" title="Dynamics (mechanics)">Dynamics</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Proper_time" title="Proper time">Proper time</a></li> <li><a href="/wiki/Invariant_mass" title="Invariant mass">Proper mass</a></li> <li><a href="/wiki/Four-momentum" title="Four-momentum">4-momentum</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style 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