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vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Biochemical_basis"> <div class="vector-toc-text"> 3 Biochemical basis </div> </a> <button aria-controls="toc-Biochemical_basis-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Biochemical basis subsection </button> <ul id="toc-Biochemical_basis-sublist" class="vector-toc-list"> <li id="toc-Harsh_environmental_conditions_on_Earth_harboring_life" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Harsh_environmental_conditions_on_Earth_harboring_life"> <div class="vector-toc-text"> 3.1 Harsh environmental conditions on Earth harboring life </div> </a> <ul id="toc-Harsh_environmental_conditions_on_Earth_harboring_life-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Planetary_habitability_in_the_Solar_System" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Planetary_habitability_in_the_Solar_System"> <div class="vector-toc-text"> 4 Planetary habitability in the Solar System </div> </a> <ul id="toc-Planetary_habitability_in_the_Solar_System-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Scientific_search" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Scientific_search"> <div class="vector-toc-text"> 5 Scientific search </div> </a> <button aria-controls="toc-Scientific_search-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Scientific search subsection </button> <ul id="toc-Scientific_search-sublist" class="vector-toc-list"> <li id="toc-Search_for_basic_life" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Search_for_basic_life"> <div class="vector-toc-text"> 5.1 Search for basic life </div> </a> <ul id="toc-Search_for_basic_life-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Search_for_extraterrestrial_intelligences" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Search_for_extraterrestrial_intelligences"> <div class="vector-toc-text"> 5.2 Search for extraterrestrial intelligences </div> </a> <ul id="toc-Search_for_extraterrestrial_intelligences-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Extrasolar_planets" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Extrasolar_planets"> <div class="vector-toc-text"> 5.3 Extrasolar planets </div> </a> <ul id="toc-Extrasolar_planets-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-History_and_cultural_impact" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History_and_cultural_impact"> <div class="vector-toc-text"> 6 History and cultural impact </div> </a> <button aria-controls="toc-History_and_cultural_impact-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle History and cultural impact subsection </button> <ul id="toc-History_and_cultural_impact-sublist" class="vector-toc-list"> <li id="toc-Cosmic_pluralism" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Cosmic_pluralism"> <div class="vector-toc-text"> 6.1 Cosmic pluralism </div> </a> <ul id="toc-Cosmic_pluralism-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Early_modern_period" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Early_modern_period"> <div class="vector-toc-text"> 6.2 Early modern period </div> </a> <ul id="toc-Early_modern_period-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-19th_century" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#19th_century"> <div class="vector-toc-text"> 6.3 19th century </div> </a> <ul id="toc-19th_century-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Recent_history" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Recent_history"> <div class="vector-toc-text"> 6.4 Recent history </div> </a> <ul id="toc-Recent_history-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Government_responses" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Government_responses"> <div class="vector-toc-text"> 7 Government responses </div> </a> <ul id="toc-Government_responses-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-In_fiction" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#In_fiction"> <div class="vector-toc-text"> 8 In fiction </div> </a> <ul id="toc-In_fiction-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> 9 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 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> 10 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 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> 11 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 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> 12 Further reading </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> 13 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">Extraterrestrial life</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 79 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-79" aria-hidden="true" > 79 languages </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af badge-Q17437796 badge-featuredarticle mw-list-item" title="featured article badge"><a href="https://af.wikipedia.org/wiki/Buiteaardse_lewe" title="Buiteaardse lewe – Afrikaans" lang="af" hreflang="af" data-title="Buiteaardse lewe" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target">Afrikaans</a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A7%D9%84%D8%AD%D9%8A%D8%A7%D8%A9_%D8%AE%D8%A7%D8%B1%D8%AC_%D8%A7%D9%84%D8%A3%D8%B1%D8%B6" title="الحياة خارج الأرض – Arabic" lang="ar" hreflang="ar" data-title="الحياة خارج الأرض" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target">العربية</a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Yerd%C9%99nk%C9%99nar_h%C9%99yat" title="Yerdənkənar həyat – Azerbaijani" lang="az" hreflang="az" data-title="Yerdənkənar həyat" 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%AC%E0%A6%B9%E0%A6%BF%E0%A6%B0%E0%A7%8D%E0%A6%9C%E0%A6%BE%E0%A6%97%E0%A6%A4%E0%A6%BF%E0%A6%95_%E0%A6%AA%E0%A7%8D%E0%A6%B0%E0%A6%BE%E0%A6%A3" title="বহির্জাগতিক প্রাণ – Bangla" lang="bn" hreflang="bn" data-title="বহির্জাগতিক প্রাণ" 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/Go%C4%81-k%C3%A0i_s%C3%A8%E2%81%BF-mi%C4%81" title="Goā-kài sèⁿ-miā – Minnan" lang="nan" hreflang="nan" data-title="Goā-kài sèⁿ-miā" 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%95%D1%80%D2%99%D3%99%D0%BD_%D1%81%D0%B8%D1%82%D1%82%D3%99%D0%B3%D0%B5_%D1%82%D0%B5%D1%80%D0%B5%D0%BA%D0%BB%D0%B5%D0%BA" title="Ерҙән ситтәге тереклек – Bashkir" lang="ba" hreflang="ba" data-title="Ерҙән ситтәге тереклек" 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%9F%D0%B0%D0%B7%D0%B0%D0%B7%D0%B5%D0%BC%D0%BD%D0%B0%D0%B5_%D0%B6%D1%8B%D1%86%D1%86%D1%91" title="Пазаземнае жыццё – Belarusian" lang="be" hreflang="be" data-title="Пазаземнае жыццё" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target">Беларуская</a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%98%D0%B7%D0%B2%D1%8A%D0%BD%D0%B7%D0%B5%D0%BC%D0%B5%D0%BD_%D0%B6%D0%B8%D0%B2%D0%BE%D1%82" title="Извънземен живот – Bulgarian" lang="bg" hreflang="bg" data-title="Извънземен живот" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target">Български</a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Buhez_arallved" title="Buhez arallved – Breton" lang="br" hreflang="br" data-title="Buhez arallved" data-language-autonym="Brezhoneg" data-language-local-name="Breton" class="interlanguage-link-target">Brezhoneg</a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Vida_extraterrestre" title="Vida extraterrestre – Catalan" lang="ca" hreflang="ca" data-title="Vida extraterrestre" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target">Català</a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Mimozemsk%C3%BD_%C5%BEivot" title="Mimozemský život – Czech" lang="cs" hreflang="cs" data-title="Mimozemský život" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target">Čeština</a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Udenjordisk_liv" title="Udenjordisk liv – Danish" lang="da" hreflang="da" data-title="Udenjordisk liv" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target">Dansk</a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Au%C3%9Ferirdisches_Leben" title="Außerirdisches Leben – German" lang="de" hreflang="de" data-title="Außerirdisches Leben" 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/Maav%C3%A4line_elu" title="Maaväline elu – Estonian" lang="et" hreflang="et" data-title="Maaväline elu" 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%95%CE%BE%CF%89%CE%B3%CE%AE%CE%B9%CE%BD%CE%B7_%CE%B6%CF%89%CE%AE" title="Εξωγήινη ζωή – Greek" lang="el" hreflang="el" data-title="Εξωγήινη ζωή" 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/Vida_extraterrestre" title="Vida extraterrestre – Spanish" lang="es" hreflang="es" data-title="Vida extraterrestre" 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/Ekstertera_vivo" title="Ekstertera vivo – Esperanto" lang="eo" hreflang="eo" data-title="Ekstertera vivo" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target">Esperanto</a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Bizi_estralurtar" title="Bizi estralurtar – Basque" lang="eu" hreflang="eu" data-title="Bizi estralurtar" 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%AD%DB%8C%D8%A7%D8%AA_%D9%81%D8%B1%D8%A7%D8%B2%D9%85%DB%8C%D9%86%DB%8C" title="حیات فرازمینی – Persian" lang="fa" hreflang="fa" data-title="حیات فرازمینی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target">فارسی</a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Vie_extraterrestre" title="Vie extraterrestre – French" lang="fr" hreflang="fr" data-title="Vie extraterrestre" 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/B%C3%BBtenierdsk_libben" title="Bûtenierdsk libben – Western Frisian" lang="fy" hreflang="fy" data-title="Bûtenierdsk libben" data-language-autonym="Frysk" data-language-local-name="Western Frisian" class="interlanguage-link-target">Frysk</a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Beatha_eachtardhomhanda" title="Beatha eachtardhomhanda – Irish" lang="ga" hreflang="ga" data-title="Beatha eachtardhomhanda" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target">Gaeilge</a></li><li class="interlanguage-link interwiki-gv mw-list-item"><a href="https://gv.wikipedia.org/wiki/Bea_neuhallooinagh" title="Bea neuhallooinagh – Manx" lang="gv" hreflang="gv" data-title="Bea neuhallooinagh" data-language-autonym="Gaelg" data-language-local-name="Manx" class="interlanguage-link-target">Gaelg</a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Vida_extraterrestre" title="Vida extraterrestre – Galician" lang="gl" hreflang="gl" data-title="Vida extraterrestre" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target">Galego</a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%99%B8%EA%B3%84%EC%83%9D%EB%AA%85" title="외계생명 – Korean" lang="ko" hreflang="ko" data-title="외계생명" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target">한국어</a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AA%E0%A4%B0%E0%A4%97%E0%A5%8D%E0%A4%B0%E0%A4%B9%E0%A5%80_%E0%A4%9C%E0%A5%80%E0%A4%B5%E0%A4%A8" title="परग्रही जीवन – Hindi" lang="hi" hreflang="hi" data-title="परग्रही जीवन" 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/Izvanzemaljski_%C5%BEivot" title="Izvanzemaljski život – Croatian" lang="hr" hreflang="hr" data-title="Izvanzemaljski život" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target">Hrvatski</a></li><li class="interlanguage-link interwiki-ig mw-list-item"><a href="https://ig.wikipedia.org/wiki/Nd%E1%BB%A5_nd%E1%BB%8B_%E1%BB%8Dz%E1%BB%8D" title="Ndụ ndị ọzọ – Igbo" lang="ig" hreflang="ig" data-title="Ndụ ndị ọzọ" data-language-autonym="Igbo" data-language-local-name="Igbo" class="interlanguage-link-target">Igbo</a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Kehidupan_ekstraterestrial" title="Kehidupan ekstraterestrial – Indonesian" lang="id" hreflang="id" data-title="Kehidupan ekstraterestrial" 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/Vita_extraterrestre" title="Vita extraterrestre – Interlingua" lang="ia" hreflang="ia" data-title="Vita extraterrestre" data-language-autonym="Interlingua" data-language-local-name="Interlingua" class="interlanguage-link-target">Interlingua</a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%97%D7%99%D7%99%D7%9D_%D7%9E%D7%97%D7%95%D7%A5_%D7%9C%D7%9B%D7%93%D7%95%D7%A8_%D7%94%D7%90%D7%A8%D7%A5" title="חיים מחוץ לכדור הארץ – Hebrew" lang="he" hreflang="he" data-title="חיים מחוץ לכדור הארץ" 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%90%E1%83%A0%E1%83%90%E1%83%9B%E1%83%98%E1%83%AC%E1%83%98%E1%83%94%E1%83%A0%E1%83%98_%E1%83%A1%E1%83%98%E1%83%AA%E1%83%9D%E1%83%AA%E1%83%AE%E1%83%9A%E1%83%94" title="არამიწიერი სიცოცხლე – Georgian" lang="ka" hreflang="ka" data-title="არამიწიერი სიცოცხლე" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target">ქართული</a></li><li class="interlanguage-link interwiki-ks mw-list-item"><a href="https://ks.wikipedia.org/wiki/%D9%86%DB%8C%D9%9A%D8%A8%D9%95%D8%B1_%D8%A2%D8%B3%D9%85%D8%A3%D9%86%D8%A0_%D8%A8%D9%84%D8%A3%DB%92" title="نیٚبٕر آسمأنؠ بلأے – Kashmiri" lang="ks" hreflang="ks" data-title="نیٚبٕر آسمأنؠ بلأے" data-language-autonym="कॉशुर / کٲشُر" data-language-local-name="Kashmiri" class="interlanguage-link-target">कॉशुर / کٲشُر</a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%91%D3%A9%D0%B3%D0%B4%D0%B5%D2%93%D0%B0%D0%BB%D0%B0%D0%BC%D0%B4%D1%8B%D2%9B_%D1%82%D1%96%D1%80%D1%88%D1%96%D0%BB%D1%96%D0%BA" title="Бөгдеғаламдық тіршілік – Kazakh" lang="kk" hreflang="kk" data-title="Бөгдеғаламдық тіршілік" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target">Қазақша</a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Vita_extranea" title="Vita extranea – Latin" lang="la" hreflang="la" data-title="Vita extranea" 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/%C4%80rpuszemes_dz%C4%ABv%C4%ABba" title="Ārpuszemes dzīvība – Latvian" lang="lv" hreflang="lv" data-title="Ārpuszemes dzīvība" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target">Latviešu</a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Ne%C5%BEemi%C5%A1ka_gyvyb%C4%97" title="Nežemiška gyvybė – Lithuanian" lang="lt" hreflang="lt" data-title="Nežemiška gyvybė" 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/Viventes_estrateran" title="Viventes estrateran – Lingua Franca Nova" lang="lfn" hreflang="lfn" data-title="Viventes estrateran" 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-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/F%C3%B6ld%C3%B6n_k%C3%ADv%C3%BCli_%C3%A9let" title="Földön kívüli élet – Hungarian" lang="hu" hreflang="hu" data-title="Földön kívüli élet" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target">Magyar</a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%92%D0%BE%D0%BD%D0%B7%D0%B5%D0%BC%D1%81%D0%BA%D0%B8_%D0%B6%D0%B8%D0%B2%D0%BE%D1%82" title="Вонземски живот – Macedonian" lang="mk" hreflang="mk" data-title="Вонземски живот" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target">Македонски</a></li><li class="interlanguage-link interwiki-mg mw-list-item"><a href="https://mg.wikipedia.org/wiki/Fiainana_ivelan-tany" title="Fiainana ivelan-tany – Malagasy" lang="mg" hreflang="mg" data-title="Fiainana ivelan-tany" data-language-autonym="Malagasy" data-language-local-name="Malagasy" class="interlanguage-link-target">Malagasy</a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%85%E0%B4%A8%E0%B5%8D%E0%B4%AF%E0%B4%97%E0%B5%8D%E0%B4%B0%E0%B4%B9%E0%B4%9C%E0%B5%80%E0%B4%B5%E0%B5%BB" title="അന്യഗ്രഹജീവൻ – Malayalam" lang="ml" hreflang="ml" data-title="അന്യഗ്രഹജീവൻ" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target">മലയാളം</a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Makhluk_luar_angkasa" title="Makhluk luar angkasa – Malay" lang="ms" hreflang="ms" data-title="Makhluk luar angkasa" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target">Bahasa Melayu</a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%A5%D0%B0%D1%80%D1%8C_%D0%B3%D0%B0%D1%80%D0%B0%D0%B3%D0%B8%D0%B9%D0%BD_%D1%81%D0%BE%D1%91%D0%BB_%D0%B8%D1%80%D0%B3%D1%8D%D0%BD%D1%88%D0%B8%D0%BB" title="Харь гарагийн соёл иргэншил – Mongolian" lang="mn" hreflang="mn" data-title="Харь гарагийн соёл иргэншил" 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%82%E1%80%BC%E1%80%AD%E1%80%AF%E1%80%9F%E1%80%BA%E1%80%9E%E1%80%AC%E1%80%B8" title="ဂြိုဟ်သား – Burmese" lang="my" hreflang="my" data-title="ဂြိုဟ်သား" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target">မြန်မာဘာသာ</a></li><li class="interlanguage-link interwiki-pcm mw-list-item"><a href="https://pcm.wikipedia.org/wiki/Extraterrestrial_laif" title="Extraterrestrial laif – Nigerian Pidgin" lang="pcm" hreflang="pcm" data-title="Extraterrestrial laif" data-language-autonym="Naijá" data-language-local-name="Nigerian Pidgin" class="interlanguage-link-target">Naijá</a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Buitenaards_leven" title="Buitenaards leven – Dutch" lang="nl" hreflang="nl" data-title="Buitenaards leven" 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%9C%B0%E7%90%83%E5%A4%96%E7%94%9F%E5%91%BD" title="地球外生命 – Japanese" lang="ja" hreflang="ja" data-title="地球外生命" 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-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Utanomjordisk_liv" title="Utanomjordisk liv – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Utanomjordisk liv" 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/Vida_extraterr%C3%A8stra" title="Vida extraterrèstra – Occitan" lang="oc" hreflang="oc" data-title="Vida extraterrèstra" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target">Occitan</a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/O%CA%BBzga_sayyoraliklar" title="Oʻzga sayyoraliklar – Uzbek" lang="uz" hreflang="uz" data-title="Oʻzga sayyoraliklar" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target">Oʻzbekcha / ўзбекча</a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D8%AE%D9%84%D8%A7%D8%A6%DB%8C_%D9%85%D8%AE%D9%84%D9%88%D9%82" title="خلائی مخلوق – Western Punjabi" lang="pnb" hreflang="pnb" data-title="خلائی مخلوق" 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/%D9%84%D9%87_%D9%86%DA%93%DB%8D_%DA%85%D8%AE%D9%87_%D8%AF_%D8%A8%D8%A7%D9%86%D8%AF%DB%90_%DA%98%D9%88%D9%86%D8%AF" title="له نړۍ څخه د باندې ژوند – Pashto" lang="ps" hreflang="ps" data-title="له نړۍ څخه د باندې ژوند" data-language-autonym="پښتو" data-language-local-name="Pashto" class="interlanguage-link-target">پښتو</a></li><li class="interlanguage-link interwiki-km mw-list-item"><a href="https://km.wikipedia.org/wiki/%E1%9E%87%E1%9E%B8%E1%9E%9C%E1%9E%B7%E1%9E%8F%E1%9E%80%E1%9F%92%E1%9E%9A%E1%9F%85%E1%9E%97%E1%9E%96" title="ជីវិតក្រៅភព – Khmer" lang="km" hreflang="km" data-title="ជីវិតក្រៅភព" data-language-autonym="ភាសាខ្មែរ" data-language-local-name="Khmer" class="interlanguage-link-target">ភាសាខ្មែរ</a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/%C5%BBycie_pozaziemskie" title="Życie pozaziemskie – Polish" lang="pl" hreflang="pl" data-title="Życie pozaziemskie" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target">Polski</a></li><li class="interlanguage-link interwiki-pt badge-Q17437798 badge-goodarticle mw-list-item" title="good article badge"><a href="https://pt.wikipedia.org/wiki/Vida_extraterrestre" title="Vida extraterrestre – Portuguese" lang="pt" hreflang="pt" data-title="Vida extraterrestre" 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/Via%C8%9B%C4%83_extraterestr%C4%83" title="Viață extraterestră – Romanian" lang="ro" hreflang="ro" data-title="Viață extraterestră" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target">Română</a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%92%D0%BD%D0%B5%D0%B7%D0%B5%D0%BC%D0%BD%D0%B0%D1%8F_%D0%B6%D0%B8%D0%B7%D0%BD%D1%8C" title="Внеземная жизнь – Russian" lang="ru" hreflang="ru" data-title="Внеземная жизнь" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target">Русский</a></li><li class="interlanguage-link interwiki-stq mw-list-item"><a href="https://stq.wikipedia.org/wiki/Buuten%C3%A4idsk_Lieuwend" title="Buutenäidsk Lieuwend – Saterland Frisian" lang="stq" hreflang="stq" data-title="Buutenäidsk Lieuwend" 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/Jeta_jasht%C3%ABtok%C3%ABsore" title="Jeta jashtëtokësore – Albanian" lang="sq" hreflang="sq" data-title="Jeta jashtëtokësore" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target">Shqip</a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B6%B4%E0%B7%92%E0%B6%A7%E0%B7%83%E0%B6%9A%E0%B7%8A%E0%B7%80%E0%B6%BD_%E0%B6%A2%E0%B7%93%E0%B7%80%E0%B7%93%E0%B6%B1%E0%B7%8A" title="පිටසක්වල ජීවීන් – Sinhala" lang="si" hreflang="si" data-title="පිටසක්වල ජීවීන්" 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/Extraterrestrial_life" title="Extraterrestrial life – Simple English" lang="en-simple" hreflang="en-simple" data-title="Extraterrestrial life" 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 mw-list-item"><a href="https://sk.wikipedia.org/wiki/Mimozemsk%C3%BD_%C5%BEivot" title="Mimozemský život – Slovak" lang="sk" hreflang="sk" data-title="Mimozemský život" 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/Nezemeljsko_%C5%BEivljenje" title="Nezemeljsko življenje – Slovenian" lang="sl" hreflang="sl" data-title="Nezemeljsko življenje" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target">Slovenščina</a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%DA%98%DB%8C%D8%A7%D9%86_%D9%84%DB%95_%D8%AF%DB%95%D8%B1%DB%95%D9%88%DB%95%DB%8C_%D8%B2%DB%95%D9%88%DB%8C" title="ژیان لە دەرەوەی زەوی – Central Kurdish" lang="ckb" hreflang="ckb" data-title="ژیان لە دەرەوەی زەوی" 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%92%D0%B0%D0%BD%D0%B7%D0%B5%D0%BC%D0%B0%D1%99%D1%81%D0%BA%D0%B8_%D0%B6%D0%B8%D0%B2%D0%BE%D1%82" title="Ванземаљски живот – Serbian" lang="sr" hreflang="sr" data-title="Ванземаљски живот" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target">Српски / srpski</a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Maan_ulkopuolinen_el%C3%A4m%C3%A4" title="Maan ulkopuolinen elämä – Finnish" lang="fi" hreflang="fi" data-title="Maan ulkopuolinen elämä" 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/Utomjordiskt_liv" title="Utomjordiskt liv – Swedish" lang="sv" hreflang="sv" data-title="Utomjordiskt liv" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target">Svenska</a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%B5%E0%AF%87%E0%AE%B1%E0%AF%8D%E0%AE%B1%E0%AF%81%E0%AE%B2%E0%AE%95_%E0%AE%89%E0%AE%AF%E0%AE%BF%E0%AE%B0%E0%AE%BF" title="வேற்றுலக உயிரி – Tamil" lang="ta" hreflang="ta" data-title="வேற்றுலக உயிரி" 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/%D2%96%D0%B8%D1%80%D0%B4%D3%99%D0%BD_%D1%87%D0%B8%D1%82%D1%82%D3%99%D0%B3%D0%B5_%D1%82%D0%B5%D1%80%D0%B5%D0%BA%D0%BB%D0%B5%D0%BA" title="Җирдән читтәге тереклек – Tatar" lang="tt" hreflang="tt" data-title="Җирдән читтәге тереклек" 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%97%E0%B1%8D%E0%B0%B0%E0%B0%B9%E0%B0%BE%E0%B0%82%E0%B0%A4%E0%B0%B0_%E0%B0%B5%E0%B0%BE%E0%B0%B8%E0%B1%81%E0%B0%B2%E0%B1%81" title="గ్రహాంతర వాసులు – Telugu" lang="te" hreflang="te" data-title="గ్రహాంతర వాసులు" 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%AA%E0%B8%B4%E0%B9%88%E0%B8%87%E0%B8%A1%E0%B8%B5%E0%B8%8A%E0%B8%B5%E0%B8%A7%E0%B8%B4%E0%B8%95%E0%B8%99%E0%B8%AD%E0%B8%81%E0%B9%82%E0%B8%A5%E0%B8%81" title="สิ่งมีชีวิตนอกโลก – Thai" lang="th" hreflang="th" data-title="สิ่งมีชีวิตนอกโลก" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target">ไทย</a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/D%C3%BCnya_d%C4%B1%C5%9F%C4%B1_ya%C5%9Fam" title="Dünya dışı yaşam – Turkish" lang="tr" hreflang="tr" data-title="Dünya dışı yaşam" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target">Türkçe</a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9F%D0%BE%D0%B7%D0%B0%D0%B7%D0%B5%D0%BC%D0%BD%D0%B5_%D0%B6%D0%B8%D1%82%D1%82%D1%8F" title="Позаземне життя – Ukrainian" lang="uk" hreflang="uk" data-title="Позаземне життя" 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%AE%D9%84%D8%A7%D8%A6%DB%8C_%D9%85%D8%AE%D9%84%D9%88%D9%82" title="خلائی مخلوق – Urdu" lang="ur" hreflang="ur" data-title="خلائی مخلوق" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target">اردو</a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/S%E1%BB%B1_s%E1%BB%91ng_ngo%C3%A0i_Tr%C3%A1i_%C4%90%E1%BA%A5t" title="Sự sống ngoài Trái Đất – Vietnamese" lang="vi" hreflang="vi" data-title="Sự sống ngoài Trái Đất" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target">Tiếng Việt</a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E5%A4%96%E6%98%9F%E7%94%9F%E5%91%BD" 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class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Life not on Earth</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">This article is about any kind of extraterrestrial life. For aliens with human-like intelligence, see <a href="/wiki/Extraterrestrial_intelligence" title="Extraterrestrial intelligence">Extraterrestrial intelligence</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1233989161">.mw-parser-output .unsolved{margin:0.5em 0 1em 1em;border:#ccc solid;padding:0.35em 0.35em 0.35em 2.2em;background-color:var(--background-color-interactive-subtle);background-image:url("https://upload.wikimedia.org/wikipedia/commons/2/26/Question%2C_Web_Fundamentals.svg");background-position:top 50%left 0.35em;background-size:1.5em;background-repeat:no-repeat}@media(min-width:720px){.mw-parser-output .unsolved{clear:right;float:right;max-width:25%}}.mw-parser-output .unsolved-label{font-weight:bold}.mw-parser-output .unsolved-body{margin:0.35em;font-style:italic}.mw-parser-output .unsolved-more{font-size:smaller}</style> <div role="note" aria-labelledby="unsolved-label-astronomy" class="unsolved"> <div>Unsolved problem in astronomy:</div> <div class="unsolved-body">Could life have arisen elsewhere? What are the <a href="/wiki/Abiogenesis" title="Abiogenesis">requirements for life</a>? Are there <a href="/wiki/Exoplanet" title="Exoplanet">exoplanets</a> like Earth? How likely is the <a href="/wiki/Extraterrestrial_intelligence" title="Extraterrestrial intelligence">evolution of intelligent life</a>?</div> <div class="unsolved-more"><a href="/wiki/List_of_unsolved_problems_in_astronomy" title="List of unsolved problems in astronomy">(more unsolved problems in astronomy)</a></div> </div> Extraterrestrial life, or alien life (colloquially, alien), is <a href="/wiki/Life" title="Life">life</a> that originates from another world rather than on <a href="/wiki/Earth" title="Earth">Earth</a>. No extraterrestrial life has yet been scientifically conclusively detected. Such life might range from simple forms such as <a href="/wiki/Prokaryote" title="Prokaryote">prokaryotes</a> to <a href="/wiki/Extraterrestrial_intelligence" title="Extraterrestrial intelligence">intelligent beings</a>, possibly bringing forth <a href="/wiki/Civilization" title="Civilization">civilizations</a> that might be <a href="/wiki/Kardashev_scale" title="Kardashev scale">far more advanced</a> than humans.<a href="#cite_note-WP-20201231-1">[1]</a><a href="#cite_note-NYT-20131118-2">[2]</a><a href="#cite_note-3">[3]</a> The <a href="/wiki/Drake_equation" title="Drake equation">Drake equation</a> speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life is known as <a href="/wiki/Astrobiology" title="Astrobiology">astrobiology</a>. Speculation about the possibility of inhabited worlds beyond Earth dates back to antiquity. Early <a href="/wiki/Christianity" title="Christianity">Christian</a> writers discussed the idea of a "plurality of worlds" as proposed by earlier thinkers such as <a href="/wiki/Democritus" title="Democritus">Democritus</a>; <a href="/wiki/Augustine_of_Hippo" title="Augustine of Hippo">Augustine</a> references <a href="/wiki/Epicurus" title="Epicurus">Epicurus</a>'s idea of innumerable worlds "throughout the boundless immensity of space" in <a href="/wiki/The_City_of_God" title="The City of God">The City of God</a>.<a href="#cite_note-4">[4]</a> <a href="/wiki/Pre-modern" class="mw-redirect" title="Pre-modern">Pre-modern</a> writers typically assumed extraterrestrial "worlds" are inhabited by living beings. <a href="/wiki/William_Vorilong" title="William Vorilong">William Vorilong</a>, in the 15th century, acknowledged the possibility <a href="/wiki/Jesus" title="Jesus">Jesus</a> could have visited extraterrestrial worlds to redeem their inhabitants.<a href="#cite_note-5">[5]</a> <a href="/wiki/Nicholas_of_Cusa" title="Nicholas of Cusa">Nicholas of Cusa</a> wrote in 1440 that Earth is "a brilliant star" like other celestial objects visible in space; which would appear similar to the <a href="/wiki/Sun" title="Sun">Sun</a>, from an exterior perspective, due to a layer of "fiery brightness" in the outer layer of the atmosphere. He theorised all extraterrestrial bodies could be inhabited by men, plants, and animals, including the Sun.<a href="#cite_note-6">[6]</a> <a href="/wiki/Ren%C3%A9_Descartes" title="René Descartes">Descartes</a> wrote that there was no means to prove the stars were not inhabited by "intelligent creatures", but their existence was a matter of speculation.<a href="#cite_note-7">[7]</a> When considering the <a href="/wiki/Atmospheric_composition" class="mw-redirect" title="Atmospheric composition">atmospheric composition</a> and ecosystems hosted by extraterrestrial bodies, extraterrestrial life can seem more speculation than reality, due to the harsh conditions and disparate chemical composition of the atmospheres,<a href="#cite_note-8">[8]</a> when compared to the life-abundant Earth. However, there are many extreme and chemically harsh ecosystems on Earth that do support forms of life and are often hypothesized to be the origin of life on Earth. <a href="/wiki/Hydrothermal_vent" title="Hydrothermal vent">Hydrothermal vents</a>,<a href="#cite_note-:0-9">[9]</a> acidic hot springs,<a href="#cite_note-10">[10]</a> and <a href="/wiki/Volcanic_lakes" class="mw-redirect" title="Volcanic lakes">volcanic lakes</a><a href="#cite_note-11">[11]</a> are examples of life forming under difficult circumstances, provide parallels to the extreme environments on other planets and support the possibility of extraterrestrial life. Since the mid-20th century, active research has taken place to look for signs of extraterrestrial life, encompassing searches for current and historic extraterrestrial life, and a narrower <a href="/wiki/Search_for_extraterrestrial_intelligence" title="Search for extraterrestrial intelligence">search for extraterrestrial intelligent life</a>. Depending on the category of search, methods range from analysis of telescope and specimen data<a href="#cite_note-NYT-20150106-DB-12">[12]</a> to radios used to detect and transmit communications.<a href="#cite_note-13">[13]</a> The concept of extraterrestrial life, and particularly extraterrestrial intelligence, has had a major cultural impact, especially <a href="/wiki/Extraterrestrials_in_fiction" title="Extraterrestrials in fiction">extraterrestrials in fiction</a>. <a href="/wiki/Science_fiction" title="Science fiction">Science fiction</a> has communicated scientific ideas, imagined a range of possibilities, and influenced public interest in and perspectives on extraterrestrial life. One shared space is the debate over the wisdom of attempting communication with extraterrestrial intelligence. Some encourage aggressive methods to try to contact intelligent extraterrestrial life. Others – citing the tendency of technologically advanced human societies to <a href="/wiki/Slavery" title="Slavery">enslave</a> or destroy less advanced societies – argue it may be dangerous to actively draw attention to Earth.<a href="#cite_note-14">[14]</a><a href="#cite_note-15">[15]</a> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Context">Context</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=1" title="Edit section: Context">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output 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.sidebar-list-title-c{padding:0 0.4em;text-align:center;margin:0 3.3em}@media(max-width:640px){body.mediawiki .mw-parser-output .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><table class="sidebar nomobile nowraplinks"><tbody><tr><td class="sidebar-top-image"><a href="/wiki/File:MarsCuriosityRover-Drilling-Sol170%2B%2B-2.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/eb/MarsCuriosityRover-Drilling-Sol170%2B%2B-2.jpg/200px-MarsCuriosityRover-Drilling-Sol170%2B%2B-2.jpg" decoding="async" width="200" height="221" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/eb/MarsCuriosityRover-Drilling-Sol170%2B%2B-2.jpg/300px-MarsCuriosityRover-Drilling-Sol170%2B%2B-2.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/eb/MarsCuriosityRover-Drilling-Sol170%2B%2B-2.jpg/400px-MarsCuriosityRover-Drilling-Sol170%2B%2B-2.jpg 2x" data-file-width="3819" data-file-height="4223" /></a></td></tr><tr><td class="sidebar-pretitle-with-top-image">This article is one of a series on:</td></tr><tr><th class="sidebar-title-with-pretitle"><a class="mw-selflink selflink">Life in the universe</a></th></tr><tr><td class="sidebar-above"> <a href="/wiki/Outline_of_extraterrestrial_life" title="Outline of extraterrestrial life">Outline</a></td></tr><tr><th class="sidebar-heading" style="background:#ddd; border-bottom:1px #fafafa solid;"> <a href="/wiki/Planetary_habitability_in_the_Solar_System" title="Planetary habitability in the Solar System">Planetary habitability in the Solar System</a></th></tr><tr><td class="sidebar-content hlist"> <ul><li><a href="/wiki/Life_on_Venus" title="Life on Venus">Venus</a></li> <li><a href="/wiki/Life" title="Life">Earth</a></li> <li><a href="/wiki/Life_on_Mars" title="Life on Mars">Mars</a></li> <li><a href="/wiki/Europa_(moon)#Habitability" title="Europa (moon)">Europa</a></li> <li><a href="/wiki/Enceladus#Potential_habitability" title="Enceladus">Enceladus</a></li> <li><a href="/wiki/Life_on_Titan" title="Life on Titan">Titan</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#ddd; border-bottom:1px #fafafa solid;"> Life outside the <a href="/wiki/Solar_System" title="Solar System">Solar System</a></th></tr><tr><td class="sidebar-content hlist"> <ul><li><a href="/wiki/List_of_potentially_habitable_exoplanets" title="List of potentially habitable exoplanets">Potentially habitable exoplanets</a></li> <li><a href="/wiki/Galactic_habitable_zone" title="Galactic habitable zone">Galactic habitable zone</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#ddd; border-bottom:1px #fafafa solid;"> Habitability of...</th></tr><tr><td class="sidebar-content hlist"> <ul><li><a href="/wiki/Habitability_of_binary_star_systems" title="Habitability of binary star systems">Binary star systems</a></li> <li><a href="/wiki/Habitability_of_natural_satellites" title="Habitability of natural satellites">Natural satellites</a></li> <li><a href="/wiki/Habitability_of_neutron_star_systems" title="Habitability of neutron star systems">Neutron star systems</a></li> <li><a href="/wiki/Habitability_of_red_dwarf_systems" title="Habitability of red dwarf systems">Red dwarf systems</a></li> <li><a href="/wiki/Habitability_of_K-type_main-sequence_star_systems" title="Habitability of K-type main-sequence star systems">K-type main-sequence star systems</a></li> <li><a href="/wiki/Habitability_of_yellow_dwarf_systems" title="Habitability of yellow dwarf systems">Yellow dwarf systems</a></li> <li><a href="/wiki/Habitability_of_F-type_main-sequence_star_systems" title="Habitability of F-type main-sequence star systems">F-type main-sequence star systems</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:Life_in_the_Universe" title="Template:Life in the Universe"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Life_in_the_Universe" title="Template talk:Life in the Universe"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Life_in_the_Universe" title="Special:EditPage/Template:Life in the Universe"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> Initially, after the <a href="/wiki/Big_Bang" title="Big Bang">Big Bang</a> the universe was too hot to allow life. <a href="/wiki/Chronology_of_the_universe" title="Chronology of the universe">15 million years later</a>, it cooled to temperate levels, but the elements that make up living things did not exist yet. The only freely available elements at that point were <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a> and <a href="/wiki/Helium" title="Helium">helium</a>. <a href="/wiki/Carbon" title="Carbon">Carbon</a> and <a href="/wiki/Oxygen" title="Oxygen">oxygen</a> (and later, <a href="/wiki/Water" title="Water">water</a>) would not appear until 50 million years later, created through stellar fusion. At that point, the difficulty for life to appear was not the temperature, but the scarcity of free heavy elements.<a href="#cite_note-16">[16]</a> <a href="/wiki/Planetary_system" title="Planetary system">Planetary systems</a> emerged, and the first <a href="/wiki/Organic_compound" title="Organic compound">organic compounds</a> may have formed in the <a href="/wiki/Protoplanetary_disk" title="Protoplanetary disk">protoplanetary disk</a> of <a href="/wiki/Cosmic_dust" title="Cosmic dust">dust grains</a> that would eventually create rocky planets like Earth. Although Earth was in a molten state after its birth and may have burned any organics that fell in it, it would have been more receptive once it cooled down.<a href="#cite_note-17">[17]</a> Once the right conditions on Earth were met, life started by a chemical process known as <a href="/wiki/Abiogenesis" title="Abiogenesis">abiogenesis</a>. Alternatively, life may have formed less frequently, then spread – by <a href="/wiki/Meteoroid" title="Meteoroid">meteoroids</a>, for example – between <a href="/wiki/Habitable_planet" class="mw-redirect" title="Habitable planet">habitable planets</a> in a process called <a href="/wiki/Panspermia" title="Panspermia">panspermia</a>.<a href="#cite_note-USRA-2010-18">[18]</a><a href="#cite_note-19">[19]</a> During most of its <a href="/wiki/Stellar_evolution" title="Stellar evolution">stellar evolution</a> stars combine hydrogen nuclei to make helium nuclei by stellar fusion, and the comparatively lighter weight of helium allows the star to release the extra energy. The process continues until the star uses all of its available fuel, with the speed of consumption being related to the size of the star. During its last stages, stars start combining helium nuclei to form carbon nuclei. The higher-sized stars can further combine carbon nuclei to create oxygen and silicon, oxygen into neon and sulfur, and so on until iron. In the end, the star blows much of its content back into the stellar medium, where it would join clouds that would eventually become new generations of stars and planets. Many of those materials are the raw components of life on Earth. As this process takes place in all the universe, said materials are ubiquitous in the cosmos and not a rarity from the Solar System.<a href="#cite_note-20">[20]</a> <a href="/wiki/Earth" title="Earth">Earth</a> is a planet in the <a href="/wiki/Solar_System" title="Solar System">Solar System</a>, a planetary system formed by a star at the center, the <a href="/wiki/Sun" title="Sun">Sun</a>, and the objects that orbit it: other planets, moons, asteroids, and comets. The sun is part of the <a href="/wiki/Milky_Way" title="Milky Way">Milky Way</a>, a <a href="/wiki/Galaxy" title="Galaxy">galaxy</a>. The Milky Way is part of the <a href="/wiki/Local_Group" title="Local Group">Local Group</a>, a <a href="/wiki/Galaxy_group" title="Galaxy group">galaxy group</a> that is in turn part of the <a href="/wiki/Laniakea_Supercluster" title="Laniakea Supercluster">Laniakea Supercluster</a>. The <a href="/wiki/Universe" title="Universe">universe</a> is composed of all similar structures in existence.<a href="#cite_note-21">[21]</a> The immense distances between celestial objects is a difficulty for the study of extraterrestrial life. So far, humans have only set foot on the <a href="/wiki/Moon" title="Moon">Moon</a> and sent robotic probes to other planets and moons in the Solar System. Although probes can withstand conditions that may be lethal to humans, the distances cause time delays: the <a href="/wiki/New_Horizons" title="New Horizons">New Horizons</a> took nine years after launch to reach <a href="/wiki/Pluto" title="Pluto">Pluto</a>.<a href="#cite_note-bennett55-22">[22]</a> No probe has ever reached extrasolar planetary systems. The <a href="/wiki/Voyager_2" title="Voyager 2">Voyager 2</a> has left the Solar System at a speed of 50,000 kilometers per hour, if it headed towards the <a href="/wiki/Alpha_Centauri" title="Alpha Centauri">Alpha Centauri</a> system, the closest one to Earth at 4.4 light years, it would reach it in 100,000 years. Under current technology such systems can only be studied by telescopes, which have limitations.<a href="#cite_note-bennett55-22">[22]</a> It is estimated that <a href="/wiki/Dark_matter" title="Dark matter">dark matter</a> has a larger amount of combined matter than stars and gas clouds, but as it plays no role on the stellar evolution of stars and planets, it is usually not taken into account by astrobiology.<a href="#cite_note-23">[23]</a> There is an area around a star, the <a href="/wiki/Circumstellar_habitable_zone" class="mw-redirect" title="Circumstellar habitable zone">circumstellar habitable zone</a> or "Goldilocks zone", where water may be at the right temperature to exist in liquid form at a planetary surface. This area is neither too close to the star, where water would become steam, nor too far away, where water would be frozen as ice. However, although useful as an approximation, <a href="/wiki/Planetary_habitability" title="Planetary habitability">planetary habitability</a> is complex and defined by several factors. Being in the habitable zone is not enough for a planet to be habitable, not even to actually have such liquid water. Venus is located in the habitable zone of the Solar System but does not have liquid water because of the conditions of its atmosphere. Jovian planets or <a href="/wiki/Gas_giant" title="Gas giant">gas giants</a> are not considered habitable even if they orbit close enough to their stars as <a href="/wiki/Hot_Jupiter" title="Hot Jupiter">hot Jupiters</a>, due to crushing atmospheric pressures.<a href="#cite_note-Neighbors-24">[24]</a> The actual distances for the habitable zones vary according to the type of star, and even the <a href="/wiki/Solar_activity" class="mw-redirect" title="Solar activity">solar activity</a> of each specific star influences the local habitability. The type of star also defines the time the habitable zone will exist, as its presence and limits will change along with the stars stellar evolution.<a href="#cite_note-25">[25]</a> The Big Bang took place 14 billion years ago, the Solar System was formed 4 and a half billion years ago, and the first hominids appeared 60 million years ago. Life on other planets may have started, evolved, given birth to extraterrestrial intelligences, and perhaps even faced a planetary extinction event millions or even billions of years ago. The brief times of existence of Earth's species, when considered from a cosmic perspective, may suggest that extraterrestrial life may be equally fleeting under such a scale.<a href="#cite_note-26">[26]</a> Life on Earth is quite ubiquitous across the planet and has adapted over time to almost all the available environments in it, <a href="/wiki/Extremophile" title="Extremophile">extremophiles</a> and the <a href="/wiki/Deep_biosphere" title="Deep biosphere">deep biosphere</a> thrive at even the most hostile ones. As a result, it is inferred that life in other celestial bodies may be equally adaptive. However, the origin of life is unrelated to its ease of adaptation, and may have stricter requirements. A celestial body may not have any life on it, even if it was habitable.<a href="#cite_note-27">[27]</a> <div class="mw-heading mw-heading2"><h2 id="Likelihood_of_existence">Likelihood of existence</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=2" title="Edit section: Likelihood of existence">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Drake_equation" title="Drake equation">Drake equation</a> and <a href="/wiki/Extraterrestrial_intelligence" title="Extraterrestrial intelligence">Extraterrestrial intelligence</a></div> It is unclear if life and intelligent life are ubiquitous in the cosmos or rare. The hypothesis of ubiquitous extraterrestrial life relies on three main ideas. The first one, the <a href="/wiki/Size_of_the_universe" class="mw-redirect" title="Size of the universe">size of the universe</a> allows for plenty of planets to have a similar habitability to Earth, and the <a href="/wiki/Age_of_the_universe" title="Age of the universe">age of the universe</a> gives enough time for a long process analog to the <a href="/wiki/History_of_Earth" title="History of Earth">history of Earth</a> to happen there. The second is that the chemical elements that make up life, such as carbon and water, are ubiquitous in the universe. The third is that the <a href="/wiki/Physical_law" class="mw-redirect" title="Physical law">physical laws</a> are universal, which means that the forces that would facilitate or prevent the existence of life would be the same ones as on Earth.<a href="#cite_note-28">[28]</a> According to this argument, made by scientists such as <a href="/wiki/Carl_Sagan" title="Carl Sagan">Carl Sagan</a> and <a href="/wiki/Stephen_Hawking" title="Stephen Hawking">Stephen Hawking</a>, it would be improbable for life not to exist somewhere else other than Earth.<a href="#cite_note-29">[29]</a><a href="#cite_note-30">[30]</a> This argument is embodied in the <a href="/wiki/Copernican_principle" title="Copernican principle">Copernican principle</a>, which states that Earth does not occupy a unique position in the Universe, and the <a href="/wiki/Mediocrity_principle" title="Mediocrity principle">mediocrity principle</a>, which states that there is nothing special about life on Earth.<a href="#cite_note-31">[31]</a> Other authors consider instead that life in the cosmos, or at least multicellular life, may be actually rare. The <a href="/wiki/Rare_Earth_hypothesis" title="Rare Earth hypothesis">Rare Earth hypothesis</a> maintains that life on Earth is possible because of a series of factors that range from the location in the galaxy and the configuration of the <a href="/wiki/Solar_System" title="Solar System">Solar System</a> to local characteristics of the planet, and that it is unlikely that all such requirements are simultaneously met by another planet. The proponents of this hypothesis consider that very little evidence suggests the existence of extraterrestrial life, and that at this point it is just a desired result and not a reasonable scientific explanation for any gathered data.<a href="#cite_note-32">[32]</a><a href="#cite_note-33">[33]</a> In 1961, astronomer and astrophysicist <a href="/wiki/Frank_Drake" title="Frank Drake">Frank Drake</a> devised the <a href="/wiki/Drake_equation" title="Drake equation">Drake equation</a> as a way to stimulate scientific dialogue at a meeting on the <a href="/wiki/Search_for_extraterrestrial_intelligence" title="Search for extraterrestrial intelligence">search for extraterrestrial intelligence</a> (SETI).<a href="#cite_note-December_2002-34">[34]</a>[<a href="/wiki/Wikipedia:NOTRS" class="mw-redirect" title="Wikipedia:NOTRS">better source needed</a>] The Drake equation is a <a href="/wiki/Probability_theory" title="Probability theory">probabilistic argument</a> used to estimate the number of active, communicative extraterrestrial civilisations in the <a href="/wiki/Milky_Way" title="Milky Way">Milky Way</a> <a href="/wiki/Galaxy" title="Galaxy">galaxy</a>. The Drake equation is: <dl><dd><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle N=R_{\ast }\cdot f_{p}\cdot n_{e}\cdot f_{\ell }\cdot f_{i}\cdot f_{c}\cdot L}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>N</mi> <mo>=</mo> <msub> <mi>R</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>∗</mo> </mrow> </msub> <mo>⋅</mo> <msub> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> </mrow> </msub> <mo>⋅</mo> <msub> <mi>n</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>e</mi> </mrow> </msub> <mo>⋅</mo> <msub> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>ℓ</mi> </mrow> </msub> <mo>⋅</mo> <msub> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> <mo>⋅</mo> <msub> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>c</mi> </mrow> </msub> <mo>⋅</mo> <mi>L</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle N=R_{\ast }\cdot f_{p}\cdot n_{e}\cdot f_{\ell }\cdot f_{i}\cdot f_{c}\cdot L}</annotation> </semantics> </math><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/df83ab73eacd94fd43a9136a2e7352b70e32fc5d" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:30.309ex; height:2.843ex;" alt="{\displaystyle N=R_{\ast }\cdot f_{p}\cdot n_{e}\cdot f_{\ell }\cdot f_{i}\cdot f_{c}\cdot L}"></dd></dl> where: <dl><dd>N = the number of Milky Way galaxy civilisations already capable of communicating across <a href="/wiki/Interplanetary_space" class="mw-redirect" title="Interplanetary space">interplanetary space</a></dd></dl> and <dl><dd>R* = the average rate of <a href="/wiki/Star_formation" title="Star formation">star formation</a> in <a href="/wiki/Milky_Way" title="Milky Way">our galaxy</a></dd> <dd>fp = the fraction of those stars that have <a href="/wiki/Planet" title="Planet">planets</a></dd> <dd>ne = the average number of planets that can potentially support life</dd> <dd>fl = the fraction of planets that actually support life</dd> <dd>fi = the fraction of planets with life that evolves to become <a href="/wiki/Intelligence" title="Intelligence">intelligent</a> life (civilisations)</dd> <dd>fc = the fraction of civilisations that develop a technology to broadcast detectable signs of their existence into space</dd> <dd>L = the length of time over which such civilisations broadcast detectable signals into space</dd></dl> Drake's proposed estimates are as follows, but numbers on the right side of the equation are agreed as speculative and open to substitution: <math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 10{,}000=5\cdot 0.5\cdot 2\cdot 1\cdot 0.2\cdot 1\cdot 10{,}000}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mn>10,000</mn> <mo>=</mo> <mn>5</mn> <mo>⋅</mo> <mn>0.5</mn> <mo>⋅</mo> <mn>2</mn> <mo>⋅</mo> <mn>1</mn> <mo>⋅</mo> <mn>0.2</mn> <mo>⋅</mo> <mn>1</mn> <mo>⋅</mo> <mn>10,000</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle 10{,}000=5\cdot 0.5\cdot 2\cdot 1\cdot 0.2\cdot 1\cdot 10{,}000}</annotation> </semantics> </math><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/9fdbafc89588f7a3ee2cd08f53edd3942914018d" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:36.685ex; height:2.509ex;" alt="{\displaystyle 10{,}000=5\cdot 0.5\cdot 2\cdot 1\cdot 0.2\cdot 1\cdot 10{,}000}"><a href="#cite_note-NOVA-35">[35]</a>[<a href="/wiki/Wikipedia:NOTRS" class="mw-redirect" title="Wikipedia:NOTRS">better source needed</a>] The Drake equation has proved controversial since, although it is written as a math equation, none of its values were known at the time. Although some values may eventually be measured, others are based on <a href="/wiki/Social_science" title="Social science">social sciences</a> and are not knowable by their very nature.<a href="#cite_note-Burchell-36">[36]</a> This does not allow one to make noteworthy conclusions from the equation.<a href="#cite_note-37">[37]</a> Based on observations from the <a href="/wiki/Hubble_Space_Telescope" title="Hubble Space Telescope">Hubble Space Telescope</a>, there are nearly 2 trillion galaxies in the observable universe.<a href="#cite_note-38">[38]</a> It is estimated that at least ten per cent of all Sun-like stars have a system of planets,<a href="#cite_note-marcyprogth05-39">[39]</a> i.e. there are 6.25×1018 stars with planets orbiting them in the observable universe. Even if it is assumed that only one out of a billion of these stars has planets supporting life, there would be some 6.25 billion life-supporting planetary systems in the observable universe. A 2013 study based on results from the <a href="/wiki/Kepler_(spacecraft)" class="mw-redirect" title="Kepler (spacecraft)">Kepler</a> spacecraft estimated that the Milky Way contains at least as many planets as it does stars, resulting in 100–400 billion exoplanets.<a href="#cite_note-Swift2013-40">[40]</a><a href="#cite_note-space20130102-41">[41]</a> The apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilisations and the lack of evidence for such civilisations is known as the <a href="/wiki/Fermi_paradox" title="Fermi paradox">Fermi paradox</a>.<a href="#cite_note-NYT-20150803-42">[42]</a> <a href="/wiki/Dennis_W._Sciama" title="Dennis W. Sciama">Dennis W. Sciama</a> claimed that life's existence in the universe depends on various fundamental constants. <a href="/w/index.php?title=Zhi-Wei_Wang&action=edit&redlink=1" class="new" title="Zhi-Wei Wang (page does not exist)">Zhi-Wei Wang</a> and <a href="/wiki/Samuel_L._Braunstein" title="Samuel L. Braunstein">Samuel L. Braunstein</a> suggest that a random universe capable of supporting life is likely to be just barely able to do so, giving a potential explanation to the Fermi paradox.<a href="#cite_note-43">[43]</a> <div class="mw-heading mw-heading2"><h2 id="Biochemical_basis">Biochemical basis</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=3" title="Edit section: Biochemical basis">edit</a>]</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/Hypothetical_types_of_biochemistry" title="Hypothetical types of biochemistry">Hypothetical types of biochemistry</a></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/Water#Effects_on_life" title="Water">Water § Effects on life</a></div> If extraterrestrial life exists, it could range from simple <a href="/wiki/Microorganism" title="Microorganism">microorganisms</a> and <a href="/wiki/Multicellular_organism" title="Multicellular organism">multicellular organisms</a> similar to animals or plants, to complex <a href="/wiki/Alien_intelligence" class="mw-redirect" title="Alien intelligence">alien intelligences</a> akin to <a href="/wiki/Human" title="Human">humans</a>. When scientists talk about extraterrestrial life, they consider all those types. Although it is possible that extraterrestrial life may have other configurations, scientists use the hierarchy of lifeforms from Earth for simplicity, as it is the only one known to exist.<a href="#cite_note-44">[44]</a> The first basic requirement for life is an environment with <a href="/wiki/Non-equilibrium_thermodynamics" title="Non-equilibrium thermodynamics">non-equilibrium thermodynamics</a>, which means that the <a href="/wiki/Thermodynamic_equilibrium" title="Thermodynamic equilibrium">thermodynamic equilibrium</a> must be broken by a source of energy. The traditional sources of energy in the cosmos are the stars, such as for life on Earth, which depends on the energy of the sun. However, there are other alternative energy sources, such as <a href="/wiki/Volcano" title="Volcano">volcanoes</a>, <a href="/wiki/Plate_tectonics" title="Plate tectonics">plate tectonics</a>, and <a href="/wiki/Hydrothermal_vent" title="Hydrothermal vent">hydrothermal vents</a>. There are ecosystems on Earth in deep areas of the ocean that do not receive sunlight, and take energy from <a href="/wiki/Black_smoker" class="mw-redirect" title="Black smoker">black smokers</a> instead.<a href="#cite_note-45">[45]</a> <a href="/wiki/Magnetic_field" title="Magnetic field">Magnetic fields</a> and <a href="/wiki/Radioactivity" class="mw-redirect" title="Radioactivity">radioactivity</a> have also been proposed as sources of energy, although they would be less efficient ones.<a href="#cite_note-46">[46]</a> Life on Earth requires water in a liquid state as a <a href="/wiki/Solvent" title="Solvent">solvent</a> in which biochemical reactions take place. It is highly unlikely that an <a href="/wiki/Abiogenesis" title="Abiogenesis">abiogenesis</a> process can start within a gaseous or solid medium: the atom speeds, either too fast or too slow, make it difficult for specific ones to meet and start chemical reactions. A liquid medium also allows the transport of nutrients and substances required for metabolism.<a href="#cite_note-47">[47]</a> Sufficient quantities of carbon and other elements, along with water, might enable the formation of living organisms on <a href="/wiki/Terrestrial_planet" title="Terrestrial planet">terrestrial planets</a> with a chemical make-up and temperature range similar to that of Earth.<a href="#cite_note-48">[48]</a><a href="#cite_note-49">[49]</a> Life based on <a href="/wiki/Ammonia" title="Ammonia">ammonia</a> rather than water has been suggested as an alternative, though this solvent appears less suitable than water. It is also conceivable that there are forms of life whose solvent is a liquid <a href="/wiki/Hydrocarbon" title="Hydrocarbon">hydrocarbon</a>, such as <a href="/wiki/Methane" title="Methane">methane</a>, <a href="/wiki/Ethane" title="Ethane">ethane</a> or <a href="/wiki/Propane" title="Propane">propane</a>.<a href="#cite_note-50">[50]</a> Another unknown aspect of potential extraterrestrial life would be the <a href="/wiki/Chemical_element" title="Chemical element">chemical elements</a> that would compose it. Life on Earth is largely composed of carbon, but there could be other <a href="/wiki/Hypothetical_types_of_biochemistry" title="Hypothetical types of biochemistry">hypothetical types of biochemistry</a>. A replacement for carbon would need to be able to create complex molecules, store information required for evolution, and be freely available in the medium. To create <a href="/wiki/DNA" title="DNA">DNA</a>, <a href="/wiki/RNA" title="RNA">RNA</a>, or a close analog, such an element should be able to bind its atoms with many others, creating complex and stable molecules. It should be able to create at least three covalent bonds: two for making long strings and at least a third to add new links and allow for diverse information. Only nine elements meet this requirement: <a href="/wiki/Boron" title="Boron">boron</a>, <a href="/wiki/Nitrogen" title="Nitrogen">nitrogen</a>, <a href="/wiki/Phosphorus" title="Phosphorus">phosphorus</a>, <a href="/wiki/Arsenic" title="Arsenic">arsenic</a>, <a href="/wiki/Antimony" title="Antimony">antimony</a> (three bonds), <a href="/wiki/Carbon" title="Carbon">carbon</a>, <a href="/wiki/Silicon" title="Silicon">silicon</a>, <a href="/wiki/Germanium" title="Germanium">germanium</a> and <a href="/wiki/Tin" title="Tin">tin</a> (four bonds). As for abundance, carbon, nitrogen, and silicon are the most abundant ones in the universe, far more than the others. On <a href="/wiki/Earth%27s_crust" title="Earth's crust">Earth's crust</a> the most abundant of those elements is silicon, in the <a href="/wiki/Hydrosphere" title="Hydrosphere">Hydrosphere</a> it is carbon and in the atmosphere, it is carbon and nitrogen. Silicon, however, has disadvantages over carbon. The molecules formed with silicon atoms are less stable, and more vulnerable to acids, oxygen, and light. An ecosystem of silicon-based lifeforms would require very low temperatures, high <a href="/wiki/Atmospheric_pressure" title="Atmospheric pressure">atmospheric pressure</a>, an atmosphere devoid of oxygen, and a solvent other than water. The low temperatures required would add an extra problem, the difficulty to kickstart a process of abiogenesis to create life in the first place.<a href="#cite_note-51">[51]</a> <a href="/wiki/Norman_Horowitz" title="Norman Horowitz">Norman Horowitz</a>, head of the Jet Propulsion Laboratory bioscience section for the Mariner and Viking missions from 1965 to 1976 considered that the great versatility of the <a href="/wiki/Carbon" title="Carbon">carbon</a> atom makes it the element most likely to provide solutions, even exotic solutions, to the problems of survival of life on other planets.<a href="#cite_note-52">[52]</a> However, he also considered that the conditions found on <a href="/wiki/Mars" title="Mars">Mars</a> were incompatible with carbon based life. Even if extraterrestrial life is based on carbon and uses water as a solvent, like Earth life, it may still have a radically different <a href="/wiki/Biochemistry" title="Biochemistry">biochemistry</a>. Life is generally considered to be a product of <a href="/wiki/Natural_selection" title="Natural selection">natural selection</a>. It has been proposed that to undergo natural selection a living entity must have the capacity to <a href="/wiki/DNA_replication" title="DNA replication">replicate</a> itself, the capacity to avoid damage/decay, and the capacity to acquire and process resources in support of the first two capacities.<a href="#cite_note-53">[53]</a> Life on Earth started with an <a href="/wiki/RNA_world" title="RNA world">RNA world</a> and later evolved to its current form, where some of the <a href="/wiki/RNA" title="RNA">RNA</a> tasks were transferred to <a href="/wiki/DNA" title="DNA">DNA</a> and <a href="/wiki/Proteins" class="mw-redirect" title="Proteins">proteins</a>. Extraterrestrial life may still be stuck using RNA, or evolve into other configurations. It is unclear if our biochemistry is the most efficient one that could be generated, or which elements would follow a similar pattern.<a href="#cite_note-54">[54]</a> However, it is likely that, even if cells had a different composition to those from Earth, they would still have a <a href="/wiki/Cell_membrane" title="Cell membrane">cell membrane</a>. Life on Earth jumped from <a href="/wiki/Prokaryote" title="Prokaryote">prokaryotes</a> to <a href="/wiki/Eukaryote" title="Eukaryote">eukaryotes</a> and from <a href="/wiki/Unicellular_organism" title="Unicellular organism">unicellular organisms</a> to multicellular organisms through <a href="/wiki/Evolution" title="Evolution">evolution</a>. So far no alternative process to achieve such a result has been conceived, even if hypothetical. Evolution requires life to be divided into individual organisms, and no alternative organisation has been satisfactorily proposed either. At the basic level, membranes define the limit of a cell, between it and its environment, while remaining partially open to exchange energy and resources with it.<a href="#cite_note-55">[55]</a> The evolution from simple cells to eukaryotes, and from them to multicellular lifeforms, is not guaranteed. The <a href="/wiki/Cambrian_explosion" title="Cambrian explosion">Cambrian explosion</a> took place thousands of millions of years after the origin of life, and its causes are not fully known yet. On the other hand, the jump to multicellularity took place several times, which suggests that it could be a case of <a href="/wiki/Convergent_evolution" title="Convergent evolution">convergent evolution</a>, and so likely to take place on other planets as well. Palaeontologist <a href="/wiki/Simon_Conway_Morris" title="Simon Conway Morris">Simon Conway Morris</a> considers that convergent evolution would lead to kingdoms similar to our plants and animals, and that many features are likely to develop in alien animals as well, such as <a href="/wiki/Bilateral_symmetry" class="mw-redirect" title="Bilateral symmetry">bilateral symmetry</a>, <a href="/wiki/Limb_(anatomy)" title="Limb (anatomy)">limbs</a>, <a href="/wiki/Digestion" title="Digestion">digestive systems</a> and heads with <a href="/wiki/Sensory_organ" class="mw-redirect" title="Sensory organ">sensory organs</a>.<a href="#cite_note-AM6166-56">[56]</a> Scientists from the University of Oxford analysed it from the perspective of evolutionary theory and wrote in a study in the <a href="/wiki/International_Journal_of_Astrobiology" title="International Journal of Astrobiology">International Journal of Astrobiology</a> that aliens may be similar to humans.<a href="#cite_note-57">[57]</a> The planetary context would also have an influence: a planet with higher <a href="/wiki/Gravity" title="Gravity">gravity</a> would have smaller animals, and other types of stars can lead to <a href="/wiki/Hypothetical_types_of_biochemistry#Non-green_photosynthesizers" title="Hypothetical types of biochemistry">non-green photosynthesizers</a>. The amount of energy available would also affect <a href="/wiki/Biodiversity" title="Biodiversity">biodiversity</a>, as an ecosystem sustained by black smokers or hydrothermal vents would have less energy available than those sustained by a star's light and heat, and so its lifeforms would not grow beyond a certain complexity.<a href="#cite_note-AM6166-56">[56]</a> There is also research in assessing the capacity of life for developing intelligence. It has been suggested that this capacity arises with the number of potential <a href="/wiki/Ecological_niche" title="Ecological niche">niches</a> a planet contains, and that the complexity of life itself is reflected in the information density of planetary environments, which in turn can be computed from its niches.<a href="#cite_note-58">[58]</a> <div class="mw-heading mw-heading3"><h3 id="Harsh_environmental_conditions_on_Earth_harboring_life">Harsh environmental conditions on Earth harboring life</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=4" title="Edit section: Harsh environmental conditions on Earth harboring life">edit</a>]</div> It is common knowledge that the conditions on other planets in the solar system, in addition to the many galaxies outside of the <a href="/wiki/Milky_Way_galaxy" class="mw-redirect" title="Milky Way galaxy">Milky Way galaxy</a>, are very harsh and seem to be too extreme to harbor any life.<a href="#cite_note-59">[59]</a> The environmental conditions on these planets can have intense <a href="/wiki/UV_radiation" class="mw-redirect" title="UV radiation">UV radiation</a> paired with extreme temperatures, lack of water,<a href="#cite_note-60">[60]</a> and much more that can lead to conditions that don't seem to favor the creation or maintenance of extraterrestrial life. However, there has been much historical evidence that some of the earliest and most basic forms of life on Earth originated in some extreme environments<a href="#cite_note-61">[61]</a> that seem unlikely to have harbored life at least at one point in Earth's history. Fossil evidence as well as many historical theories backed up by years of research and studies have marked environments like <a href="/wiki/Hydrothermal_vent" title="Hydrothermal vent">hydrothermal vents</a> or acidic hot springs as some of the first places that life could have originated on Earth.<a href="#cite_note-62">[62]</a> These environments can be considered extreme when compared to the typical ecosystems that the majority of life on Earth now inhabit, as hydrothermal vents are scorching hot due to the <a href="/wiki/Magma" title="Magma">magma</a> escaping from the <a href="/wiki/Earth%27s_mantle" title="Earth's mantle">Earth's mantle</a> and meeting the much colder oceanic water. Even in today's world, there can be a diverse population of bacteria found inhabiting the area surrounding these hydrothermal vents<a href="#cite_note-:1-63">[63]</a> which can suggest that some form of life can be supported even in the harshest of environments like the other planets in the solar system. The aspects of these harsh environments that make them ideal for the origin of life on Earth, as well as the possibility of creation of life on other planets, is the <a href="/wiki/Chemical_reaction" title="Chemical reaction">chemical reactions</a> forming spontaneously. For example, the <a href="/wiki/Hydrothermal_vent" title="Hydrothermal vent">hydrothermal vents</a> found on the ocean floor are known to support many <a href="/wiki/Chemosynthesis" title="Chemosynthesis">chemosynthetic</a> processes<a href="#cite_note-:0-9">[9]</a> which allow organisms to utilize energy through reduced chemical compounds that fix carbon.<a href="#cite_note-:1-63">[63]</a> In return, these reactions will allow for organisms to live in relatively low oxygenated environments while maintaining enough energy to support themselves. The early Earth environment was reducing<a href="#cite_note-64">[64]</a> and therefore, these carbon fixing compounds were necessary for the survival and possible <a href="/wiki/Origin_of_life_on_Earth" class="mw-redirect" title="Origin of life on Earth">origin of life on Earth</a>. With the little amount of information that scientists have found regarding the atmosphere on other planets in the <a href="/wiki/Milky_Way_galaxy" class="mw-redirect" title="Milky Way galaxy">Milky Way galaxy</a> and beyond, the atmospheres are most likely reducing or with very low oxygen levels,<a href="#cite_note-65">[65]</a> especially when compared with Earth's atmosphere. If there were the necessary elements and ions on these planets, the same carbon fixing, reduced chemical compounds occurring around hydrothermal vents could also occur on these planets' surfaces and possibly result in the origin of extraterrestrial life. <div class="mw-heading mw-heading2"><h2 id="Planetary_habitability_in_the_Solar_System">Planetary habitability in the Solar System</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=5" title="Edit section: Planetary habitability in the Solar System">edit</a>]</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/Planetary_habitability_in_the_Solar_System" title="Planetary habitability in the Solar System">Planetary habitability in the Solar System</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Habitable_Worlds_2.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Habitable_Worlds_2.jpg/220px-Habitable_Worlds_2.jpg" decoding="async" width="220" height="431" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Habitable_Worlds_2.jpg/330px-Habitable_Worlds_2.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Habitable_Worlds_2.jpg/440px-Habitable_Worlds_2.jpg 2x" data-file-width="635" data-file-height="1245" /></a><figcaption>Besides Earth, <a href="/wiki/Mars" title="Mars">Mars</a>, <a href="/wiki/Europa_(moon)" title="Europa (moon)">Europa</a> and <a href="/wiki/Enceladus" title="Enceladus">Enceladus</a> are the most likely places in the Solar System to find life.</figcaption></figure> The Solar System has a wide variety of planets, dwarf planets, and moons, and each one is studied for its potential to host life. Each one has its own specific conditions that may benefit or harm life. So far, the only lifeforms found are those from Earth. No <a href="/wiki/Extraterrestrial_intelligence" title="Extraterrestrial intelligence">extraterrestrial intelligence</a> other than <a href="/wiki/Human" title="Human">humans</a> exists or has ever existed within the Solar System.<a href="#cite_note-66">[66]</a> Astrobiologist Mary Voytek points out that it would be unlikely to find large ecosystems, as they would have already been detected by now.<a href="#cite_note-Neighbors-24">[24]</a> The inner Solar System is likely devoid of life. However, <a href="/wiki/Venus" title="Venus">Venus</a> is still of interest to astrobiologists, as it is a <a href="/wiki/Terrestrial_planet" title="Terrestrial planet">terrestrial planet</a> that was likely similar to Earth in its early stages and developed in a different way. There is a <a href="/wiki/Greenhouse_effect" title="Greenhouse effect">greenhouse effect</a>, the surface is the hottest in the Solar System, sulfuric acid clouds, all surface liquid water is lost, and it has a thick carbon-dioxide atmosphere with huge pressure.<a href="#cite_note-67">[67]</a> Comparing both helps to understand the precise differences that lead to beneficial or harmful conditions for life. And despite the conditions against <a href="/wiki/Life_on_Venus" title="Life on Venus">life on Venus</a>, there are suspicions that microbial life-forms may still survive in high-altitude clouds.<a href="#cite_note-Neighbors-24">[24]</a> <a href="/wiki/Mars" title="Mars">Mars</a> is a cold and almost airless desert, inhospitable to life. However, recent studies revealed that <a href="/wiki/Water_on_Mars" title="Water on Mars">water on Mars</a> used to be quite abundant, forming rivers, lakes, and perhaps even oceans. Mars may have been habitable back then, and <a href="/wiki/Life_on_Mars" title="Life on Mars">life on Mars</a> may have been possible. But when the planetary core ceased to generate a magnetic field, solar winds removed the atmosphere and the planet became vulnerable to solar radiation. Ancient life-forms may still have left fossilised remains, and microbes may still survive deep underground.<a href="#cite_note-Neighbors-24">[24]</a> As mentioned, the gas giants and <a href="/wiki/Ice_giants" class="mw-redirect" title="Ice giants">ice giants</a> are unlikely to contain life. The most distant solar system bodies, found in the <a href="/wiki/Kuiper_Belt" class="mw-redirect" title="Kuiper Belt">Kuiper Belt</a> and outwards, are locked in permanent deep-freeze, but cannot be ruled out completely.<a href="#cite_note-Neighbors-24">[24]</a> Although the giant planets themselves are highly unlikely to have life, there is much hope to find it on moons orbiting these planets. <a href="/wiki/Europa_(moon)" title="Europa (moon)">Europa</a>, from the Jovian system, has a subsurface ocean below a thick layer of ice. <a href="/wiki/Ganymede_(moon)" title="Ganymede (moon)">Ganymede</a> and <a href="/wiki/Callisto_(moon)" title="Callisto (moon)">Callisto</a> also have subsurface oceans, but life is less likely in them because water is sandwiched between layers of solid ice. Europa would have contact between the ocean and the rocky surface, which helps the chemical reactions. It may be difficult to dig so deep in order to study those oceans, though. <a href="/wiki/Enceladus" title="Enceladus">Enceladus</a>, a tiny moon of <a href="/wiki/Saturn" title="Saturn">Saturn</a> with another subsurface ocean, may not need to be dug, as it releases water to space in <a href="/wiki/Eruption_column" title="Eruption column">eruption columns</a>. The space probe <a href="/wiki/Cassini%E2%80%93Huygens" title="Cassini–Huygens">Cassini</a> flew inside one of these, but could not make a full study because NASA did not expect this phenomenon and did not equip the probe to study ocean water. Still, Cassini detected complex organic molecules, salts, evidence of hydrothermal activity, hydrogen, and methane.<a href="#cite_note-Neighbors-24">[24]</a> <a href="/wiki/Titan_(moon)" title="Titan (moon)">Titan</a> is the only celestial body in the Solar System besides Earth that has liquid bodies on the surface. It has rivers, lakes, and rain of hydrocarbons, methane, and ethane, and even a cycle similar to Earth's <a href="/wiki/Water_cycle" title="Water cycle">water cycle</a>. This special context encourages speculations about <a href="/wiki/Life_on_Titan" title="Life on Titan">lifeforms</a> with different biochemistry, but the cold temperatures would make such chemistry take place at a very slow pace. Water is rock-solid on the surface, but Titan does have a subsurface water ocean like several other moons. However, it is of such a great depth that it would be very difficult to access it for study.<a href="#cite_note-Neighbors-24">[24]</a> <div class="mw-heading mw-heading2"><h2 id="Scientific_search">Scientific search</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=6" title="Edit section: Scientific search">edit</a>]</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/Astrobiology" title="Astrobiology">Astrobiology</a></div> The science that searches and studies life in the universe, both on Earth and elsewhere, is called <a href="/wiki/Astrobiology" title="Astrobiology">astrobiology</a>. With the study of Earth's life, the only known form of life, astrobiology seeks to study how life starts and evolves and the requirements for its continuous existence. This helps to determine what to look for when searching for life in other celestial bodies. This is a complex area of study, and uses the combined perspectives of several scientific disciplines, such as <a href="/wiki/Astronomy" title="Astronomy">astronomy</a>, <a href="/wiki/Biology" title="Biology">biology</a>, <a href="/wiki/Chemistry" title="Chemistry">chemistry</a>, <a href="/wiki/Geology" title="Geology">geology</a>, <a href="/wiki/Planetary_oceanography" title="Planetary oceanography">oceanography</a>, and <a href="/wiki/Atmospheric_science" title="Atmospheric science">atmospheric sciences</a>.<a href="#cite_note-68">[68]</a> The scientific search for extraterrestrial life is being carried out both directly and indirectly. As of September 2017<a class="external text" href="https://en.wikipedia.org/w/index.php?title=Extraterrestrial_life&action=edit">[update]</a>, 3,667 <a href="/wiki/Exoplanet" title="Exoplanet">exoplanets</a> in 2,747 <a href="/wiki/Planetary_system" title="Planetary system">systems</a> have been <a href="/wiki/Exoplanet" title="Exoplanet">identified</a>, and other planets and moons in the <a href="/wiki/Solar_System" title="Solar System">Solar System</a> hold the potential for hosting primitive life such as <a href="/wiki/Microorganism" title="Microorganism">microorganisms</a>. As of 8 February 2021, an updated status of studies considering the possible detection of <a href="/wiki/Lifeform" class="mw-redirect" title="Lifeform">lifeforms</a> on Venus (via <a href="/wiki/Phosphine" title="Phosphine">phosphine</a>) and Mars (via <a href="/wiki/Methane" title="Methane">methane</a>) was reported.<a href="#cite_note-NYT-20210208-69">[69]</a> <div class="mw-heading mw-heading3"><h3 id="Search_for_basic_life">Search for basic life</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=7" title="Edit section: Search for basic life">edit</a>]</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:NASA-WhatBiosignaturesDoesLifeProduce-20180625.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1e/NASA-WhatBiosignaturesDoesLifeProduce-20180625.jpg/170px-NASA-WhatBiosignaturesDoesLifeProduce-20180625.jpg" decoding="async" width="170" height="272" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1e/NASA-WhatBiosignaturesDoesLifeProduce-20180625.jpg/255px-NASA-WhatBiosignaturesDoesLifeProduce-20180625.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1e/NASA-WhatBiosignaturesDoesLifeProduce-20180625.jpg/340px-NASA-WhatBiosignaturesDoesLifeProduce-20180625.jpg 2x" data-file-width="422" data-file-height="675" /></a><figcaption>Lifeforms produce a variety of biosignatures that may be detectable by telescopes.<a href="#cite_note-NASA-20180625-70">[70]</a><a href="#cite_note-EA-20180625-71">[71]</a></figcaption></figure> Scientists search for <a href="/wiki/Biosignature" title="Biosignature">biosignatures</a> within the <a href="/wiki/Solar_System" title="Solar System">Solar System</a> by studying planetary surfaces and examining <a href="/wiki/Meteoroid" title="Meteoroid">meteorites</a>. Some claim to have identified evidence that microbial life has existed on Mars.<a href="#cite_note-disbelief-72">[72]</a><a href="#cite_note-life-73">[73]</a><a href="#cite_note-NASA-20140227-74">[74]</a><a href="#cite_note-SP-20140228-75">[75]</a> In 1996, a controversial report stated that structures resembling <a href="/wiki/Nanobacterium" title="Nanobacterium">nanobacteria</a> were discovered in a meteorite, <a href="/wiki/ALH84001" class="mw-redirect" title="ALH84001">ALH84001</a>, formed of <a href="/wiki/Martian_meteorite" title="Martian meteorite">rock ejected from Mars</a>.<a href="#cite_note-disbelief-72">[72]</a><a href="#cite_note-life-73">[73]</a> Although all the unusual properties of the meteorite were eventually explained as the result of inorganic processes, the controversy over its discovery laid the groundwork for the development of astrobiology.<a href="#cite_note-disbelief-72">[72]</a> An experiment on the two <a href="/wiki/Viking_program" title="Viking program">Viking</a> Mars landers reported gas emissions from heated Martian soil samples that some scientists argue are consistent with the presence of living microorganisms.<a href="#cite_note-Chambers-76">[76]</a> Lack of corroborating evidence from other experiments on the same samples suggests that a non-biological reaction is a more likely hypothesis.<a href="#cite_note-Chambers-76">[76]</a><a href="#cite_note-77">[77]</a><a href="#cite_note-Beegle-78">[78]</a><a href="#cite_note-79">[79]</a> In February 2005 NASA scientists reported they may have found some evidence of extraterrestrial life on Mars.<a href="#cite_note-80">[80]</a> The two scientists, Carol Stoker and Larry Lemke of NASA's <a href="/wiki/Ames_Research_Center" title="Ames Research Center">Ames Research Center</a>, based their claim on methane signatures found in Mars's atmosphere resembling the methane production of some forms of primitive life on Earth, as well as on their own study of primitive life near the <a href="/wiki/Rio_Tinto_river" class="mw-redirect" title="Rio Tinto river">Rio Tinto river</a> in Spain. NASA officials soon distanced NASA from the scientists' claims, and Stoker herself backed off from her initial assertions.<a href="#cite_note-81">[81]</a> In November 2011, NASA launched the <a href="/wiki/Mars_Science_Laboratory" title="Mars Science Laboratory">Mars Science Laboratory</a> that landed the Curiosity rover on Mars. It is designed to assess the past and present habitability on Mars using a variety of scientific instruments. The rover landed on Mars at <a href="/wiki/Gale_(crater)" title="Gale (crater)">Gale Crater</a> in August 2012.<a href="#cite_note-Gale_Crater2-82">[82]</a><a href="#cite_note-Gale_Crater3-83">[83]</a> A group of scientists at Cornell University started a catalog of microorganisms, with the way each one reacts to sunlight. The goal is to help with the search for similar organisms in exoplanets, as the starlight reflected by planets rich in such organisms would have a specific spectrum, unlike that of starlight reflected from lifeless planets. If Earth was studied from afar with this system, it would reveal a shade of green, as a result of the abundance of plants with photosynthesis.<a href="#cite_note-ColorCatalog-84">[84]</a> In August 2011, NASA studied <a href="/wiki/Meteorite" title="Meteorite">meteorites</a> found on Antarctica, finding <a href="/wiki/Adenine" title="Adenine">adenine</a>, <a href="/wiki/Guanine" title="Guanine">guanine</a>, <a href="/wiki/Hypoxanthine" title="Hypoxanthine">hypoxanthine</a> and <a href="/wiki/Xanthine" title="Xanthine">xanthine</a>. Adenine and guanine are components of DNA, and the others are used in other biological processes. The studies ruled out pollution of the meteorites on Earth, as those components would not be freely available the way they were found in the samples. This discovery suggests that several <a href="/wiki/Organic_molecules" class="mw-redirect" title="Organic molecules">organic molecules</a> that serve as building blocks of life may be generated within asteroids and comets.<a href="#cite_note-Callahan-85">[85]</a><a href="#cite_note-Steigerwald-86">[86]</a> In October 2011, scientists reported that <a href="/wiki/Cosmic_dust" title="Cosmic dust">cosmic dust</a> contains complex <a href="/wiki/Organic_compound" title="Organic compound">organic compounds</a> ("amorphous organic solids with a mixed <a href="/wiki/Aromatic" class="mw-redirect" title="Aromatic">aromatic</a>-<a href="/wiki/Aliphatic" class="mw-redirect" title="Aliphatic">aliphatic</a> structure") that could be created naturally, and rapidly, by <a href="/wiki/Stars" class="mw-redirect" title="Stars">stars</a>.<a href="#cite_note-Space-20111026-87">[87]</a><a href="#cite_note-ScienceDaily-20111026-88">[88]</a><a href="#cite_note-Nature-20111026-89">[89]</a> It is still unclear if those compounds played a role in the creation of life on Earth, but Sun Kwok, of the University of Hong Kong, thinks so. "If this is the case, life on Earth may have had an easier time getting started as these organics can serve as basic ingredients for life."<a href="#cite_note-Space-20111026-87">[87]</a> In August 2012, and in a world first, astronomers at <a href="/wiki/Copenhagen_University" class="mw-redirect" title="Copenhagen University">Copenhagen University</a> reported the detection of a specific sugar molecule, <a href="/wiki/Glycolaldehyde" title="Glycolaldehyde">glycolaldehyde</a>, in a distant star system. The molecule was found around the <a href="/wiki/Protostar" title="Protostar">protostellar</a> binary <a href="/wiki/IRAS_16293%E2%88%922422" title="IRAS 16293−2422">IRAS 16293-2422</a>, which is located 400 light years from Earth.<a href="#cite_note-90">[90]</a> Glycolaldehyde is needed to form <a href="/wiki/Ribonucleic_acid" class="mw-redirect" title="Ribonucleic acid">ribonucleic acid</a>, or RNA, which is similar in function to DNA. This finding suggests that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation.<a href="#cite_note-91">[91]</a> In December 2023, astronomers reported the first time discovery, in the <a href="/wiki/Plume_(fluid_dynamics)" title="Plume (fluid dynamics)">plumes</a> of <a href="/wiki/Enceladus" title="Enceladus">Enceladus</a>, moon of the planet <a href="/wiki/Saturn" title="Saturn">Saturn</a>, of <a href="/wiki/Hydrogen_cyanide" title="Hydrogen cyanide">hydrogen cyanide</a>, a possible chemical essential for <a href="/wiki/Life" title="Life">life</a><a href="#cite_note-ATL-20231205-92">[92]</a> as we know it, as well as other <a href="/wiki/Organic_molecule" class="mw-redirect" title="Organic molecule">organic molecules</a>, some of which are yet to be better identified and understood. According to the researchers, "these [newly discovered] compounds could potentially support extant <a href="/wiki/Microorganism" title="Microorganism">microbial communities</a> or drive complex <a href="/wiki/Organic_synthesis" title="Organic synthesis">organic synthesis</a> leading to the <a href="/wiki/Origin_of_life" class="mw-redirect" title="Origin of life">origin of life</a>."<a href="#cite_note-NYT-20231214kc-93">[93]</a><a href="#cite_note-NA-20231214-94">[94]</a> <div class="mw-heading mw-heading3"><h3 id="Search_for_extraterrestrial_intelligences">Search for extraterrestrial intelligences</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=8" title="Edit section: Search for extraterrestrial intelligences">edit</a>]</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/Search_for_extraterrestrial_intelligence" title="Search for extraterrestrial intelligence">Search for extraterrestrial intelligence</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Green_Bank_100m_diameter_Radio_Telescope.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Green_Bank_100m_diameter_Radio_Telescope.jpg/220px-Green_Bank_100m_diameter_Radio_Telescope.jpg" decoding="async" width="220" height="148" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Green_Bank_100m_diameter_Radio_Telescope.jpg/330px-Green_Bank_100m_diameter_Radio_Telescope.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Green_Bank_100m_diameter_Radio_Telescope.jpg/440px-Green_Bank_100m_diameter_Radio_Telescope.jpg 2x" data-file-width="1200" data-file-height="808" /></a><figcaption>The <a href="/wiki/Green_Bank_Telescope" title="Green Bank Telescope">Green Bank Telescope</a> is one of the <a href="/wiki/Radio_telescope" title="Radio telescope">radio telescopes</a> used by the <a href="/wiki/Breakthrough_Listen" title="Breakthrough Listen">Breakthrough Listen</a> project to search for alien communications.</figcaption></figure> Although most searches are focused on the biology of extraterrestrial life, an extraterrestrial intelligence capable enough to develop a <a href="/wiki/Civilization" title="Civilization">civilization</a> may be detectable by other means as well. Technology may generate <a href="/wiki/Technosignature" title="Technosignature">technosignatures</a>, effects on the native planet that may not be caused by natural causes. There are three main types of techno-signatures considered: <a href="/wiki/Interstellar_communication" title="Interstellar communication">interstellar communications</a>, effects on the atmosphere, and planetary-sized structures such as <a href="/wiki/Dyson_sphere" title="Dyson sphere">Dyson spheres</a>.<a href="#cite_note-techno-95">[95]</a> Organizations such as the <a href="/wiki/SETI_Institute" title="SETI Institute">SETI Institute</a> search the cosmos for potential forms of communication. They started with <a href="/wiki/Radio_waves" class="mw-redirect" title="Radio waves">radio waves</a>, and now search for <a href="/wiki/Laser_pulse" class="mw-redirect" title="Laser pulse">laser pulses</a> as well. The challenge for this search is that there are natural sources of such signals as well, such as gamma-ray bursts and supernovae, and the difference between a natural signal and an artificial one would be in its specific patterns. Astronomers intend to use <a href="/wiki/Artificial_intelligence" title="Artificial intelligence">artificial intelligence</a> for this, as it can manage large amounts of data and is devoid of biases and preconceptions.<a href="#cite_note-techno-95">[95]</a> Besides, even if there is an advanced extraterrestrial civilization, there is no guarantee that it is transmitting radio communications in the direction of Earth. The length of time required for a signal to travel across space means that a potential answer may arrive decades or centuries after the initial message.<a href="#cite_note-96">[96]</a> The atmosphere of Earth is rich in <a href="/wiki/Nitrogen_dioxide" title="Nitrogen dioxide">nitrogen dioxide</a> as a result of <a href="/wiki/Air_pollution" title="Air pollution">air pollution</a>, which can be detectable. The natural abundance of carbon, which is also relatively reactive, makes it likely to be a basic component of the development of a potential extraterrestrial technological civilization, as it is on Earth. <a href="/wiki/Fossil_fuel" title="Fossil fuel">Fossil fuels</a> may likely be generated and used on such worlds as well. The abundance of <a href="/wiki/Chlorofluorocarbon" title="Chlorofluorocarbon">chlorofluorocarbons</a> in the atmosphere can also be a clear technosignature, considering their role in <a href="/wiki/Ozone_depletion" title="Ozone depletion">ozone depletion</a>. <a href="/wiki/Light_pollution" title="Light pollution">Light pollution</a> may be another technosignature, as multiple lights on the night side of a rocky planet can be a sign of advanced technological development. However, modern telescopes are not strong enough to study exoplanets with the required level of detail to perceive it.<a href="#cite_note-techno-95">[95]</a> The <a href="/wiki/Kardashev_scale" title="Kardashev scale">Kardashev scale</a> proposes that a civilization may eventually start consuming energy directly from its local star. This would require giant structures built next to it, called Dyson spheres. Those speculative structures would cause an excess infrared radiation, that telescopes may notice. The infrared radiation is typical of young stars, surrounded by dusty <a href="/wiki/Protoplanetary_disk" title="Protoplanetary disk">protoplanetary disks</a> that will eventually form planets. An older star such as the Sun would have no natural reason to have excess infrared radiation.<a href="#cite_note-techno-95">[95]</a> The presence of heavy elements in a star's light-spectrum is another potential <a href="/wiki/Biosignature" title="Biosignature">biosignature</a>; such elements would (in theory) be found if the star were being used as an incinerator/repository for nuclear waste products.<a href="#cite_note-97">[97]</a> <div class="mw-heading mw-heading3"><h3 id="Extrasolar_planets">Extrasolar planets</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=9" title="Edit section: Extrasolar planets">edit</a>]</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/Exoplanet" title="Exoplanet">Exoplanet</a></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/List_of_potentially_habitable_exoplanets" title="List of potentially habitable exoplanets">List of potentially habitable exoplanets</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Glieseupdated.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Glieseupdated.jpg/220px-Glieseupdated.jpg" decoding="async" width="220" height="167" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Glieseupdated.jpg/330px-Glieseupdated.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Glieseupdated.jpg/440px-Glieseupdated.jpg 2x" data-file-width="647" data-file-height="491" /></a><figcaption>Artist's impression of <a href="/wiki/Gliese_581_c" class="mw-redirect" title="Gliese 581 c">Gliese 581 c</a>, the first <a href="/wiki/Terrestrial_planet" title="Terrestrial planet">terrestrial extrasolar planet</a> discovered within its star's habitable zone</figcaption></figure> Some astronomers search for <a href="/wiki/Exoplanet" title="Exoplanet">extrasolar planets</a> that may be conducive to life, narrowing the search to <a href="/wiki/Terrestrial_planet" title="Terrestrial planet">terrestrial planets</a> within the habitable zones of their stars.<a href="#cite_note-Earth-likeplanet1-98">[98]</a><a href="#cite_note-GlieseSpace-99">[99]</a> Since 1992, over four thousand exoplanets have been discovered (7,026 planets in 4,949 planetary systems including 1007 <a href="/wiki/List_of_multiplanetary_systems" title="List of multiplanetary systems">multiple planetary systems</a> as of 24 July 2024).<a href="#cite_note-Encyclopaedia-100">[100]</a> The extrasolar planets so far discovered range in size from that of terrestrial planets similar to Earth's size to that of gas giants larger than Jupiter.<a href="#cite_note-Encyclopaedia-100">[100]</a> The number of observed exoplanets is expected to increase greatly in the coming years.<a href="#cite_note-101">[101]</a>[<a href="/wiki/Wikipedia:NOTRS" class="mw-redirect" title="Wikipedia:NOTRS">better source needed</a>] The <a href="/wiki/Kepler_space_telescope" title="Kepler space telescope">Kepler space telescope</a> has also detected a few thousand<a href="#cite_note-keplersite-102">[102]</a><a href="#cite_note-usher-103">[103]</a> candidate planets,<a href="#cite_note-104">[104]</a><a href="#cite_note-mygoditsfullofplanets-105">[105]</a> of which about 11% may be <a href="/wiki/False_positive" class="mw-redirect" title="False positive">false positives</a>.<a href="#cite_note-106">[106]</a> There is at least one planet on average per star.<a href="#cite_note-Nature-20120111-107">[107]</a> About 1 in 5 <a href="/wiki/Solar_analog" title="Solar analog">Sun-like stars</a><a href="#cite_note-footnoteA-108">[a]</a> have an "Earth-sized"<a href="#cite_note-footnoteB-109">[b]</a> planet in the habitable zone,<a href="#cite_note-footnoteC-110">[c]</a> with the nearest expected to be within 12 light-years distance from Earth.<a href="#cite_note-ucb1in5-111">[108]</a><a href="#cite_note-earthsunhzprev-112">[109]</a> Assuming 200 billion stars in the Milky Way,<a href="#cite_note-footnoteD-113">[d]</a> that would be 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if <a href="/wiki/Red_dwarf" title="Red dwarf">red dwarfs</a> are included.<a href="#cite_note-114">[110]</a> The <a href="/wiki/Rogue_planet" title="Rogue planet">rogue planets</a> in the Milky Way possibly number in the trillions.<a href="#cite_note-115">[111]</a> The nearest known exoplanet is <a href="/wiki/Proxima_Centauri_b" title="Proxima Centauri b">Proxima Centauri b</a>, located 4.2 <a href="/wiki/Light-year" title="Light-year">light-years</a> (1.3 <a href="/wiki/Parsec" title="Parsec">pc</a>) from Earth in the southern <a href="/wiki/Constellation" title="Constellation">constellation</a> of <a href="/wiki/Centaurus" title="Centaurus">Centaurus</a>.<a href="#cite_note-nyt20160824-116">[112]</a> As of March 2014<a class="external text" href="https://en.wikipedia.org/w/index.php?title=Extraterrestrial_life&action=edit">[update]</a>, the <a href="/wiki/List_of_exoplanet_extremes#Planetary_characteristics" title="List of exoplanet extremes">least massive exoplanet</a> known is <a href="/wiki/PSR_B1257%2B12_A" title="PSR B1257+12 A">PSR B1257+12 A</a>, which is about twice the mass of the <a href="/wiki/Moon" title="Moon">Moon</a>. The <a href="/wiki/List_of_exoplanet_extremes#Planetary_characteristics" title="List of exoplanet extremes">most massive planet</a> listed on the <a href="/wiki/NASA_Exoplanet_Archive" title="NASA Exoplanet Archive">NASA Exoplanet Archive</a> is <a href="/wiki/DENIS-P_J082303.1%E2%88%92491201_b" title="DENIS-P J082303.1−491201 b">DENIS-P J082303.1−491201 b</a>,<a href="#cite_note-CT-Exo-2014-117">[113]</a><a href="#cite_note-HU-201308-118">[114]</a> about 29 times the mass of <a href="/wiki/Jupiter" title="Jupiter">Jupiter</a>, although according to most definitions of a <a href="/wiki/Planet" title="Planet">planet</a>, it is too massive to be a planet and may be a <a href="/wiki/Brown_dwarf" title="Brown dwarf">brown dwarf</a> instead. Almost all of the planets detected so far are within the Milky Way, but there have also been a few possible detections of <a href="/wiki/Extragalactic_planet" title="Extragalactic planet">extragalactic planets</a>. The study of <a href="/wiki/Planetary_habitability" title="Planetary habitability">planetary habitability</a> also considers a wide range of other factors in determining the suitability of a planet for hosting life.<a href="#cite_note-NYT-20150106-DB-12">[12]</a> One sign that a planet probably already contains life is the presence of an atmosphere with significant amounts of <a href="/wiki/Oxygen" title="Oxygen">oxygen</a>, since that gas is highly reactive and generally would not last long without constant replenishment. This replenishment occurs on Earth through photosynthetic organisms. One way to analyse the atmosphere of an exoplanet is through <a href="/wiki/Spectrography" class="mw-redirect" title="Spectrography">spectrography</a> when it <a href="/wiki/Transit_(astronomy)" class="mw-redirect" title="Transit (astronomy)">transits</a> its star, though this might only be feasible with dim stars like <a href="/wiki/White_dwarf" title="White dwarf">white dwarfs</a>.<a href="#cite_note-hscfa20130225-119">[115]</a> <div class="mw-heading mw-heading2"><h2 id="History_and_cultural_impact">History and cultural impact</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=10" title="Edit section: History and cultural impact">edit</a>]</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/History_of_the_extraterrestrial_life_debate" title="History of the extraterrestrial life debate">History of the extraterrestrial life debate</a></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_astronomy" title="History of astronomy">History of astronomy</a> and <a href="/wiki/Potential_cultural_impact_of_extraterrestrial_contact" title="Potential cultural impact of extraterrestrial contact">Potential cultural impact of extraterrestrial contact</a></div> <div class="mw-heading mw-heading3"><h3 id="Cosmic_pluralism">Cosmic pluralism</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=11" title="Edit section: Cosmic pluralism">edit</a>]</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/Cosmic_pluralism" title="Cosmic pluralism">Cosmic pluralism</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Epikouros_BM_1843.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/88/Epikouros_BM_1843.jpg/170px-Epikouros_BM_1843.jpg" decoding="async" width="170" height="255" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/88/Epikouros_BM_1843.jpg/255px-Epikouros_BM_1843.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/88/Epikouros_BM_1843.jpg/340px-Epikouros_BM_1843.jpg 2x" data-file-width="2533" data-file-height="3800" /></a><figcaption>The Greek <a href="/wiki/Epicurus" title="Epicurus">Epicurus</a> proposed that other worlds may have their own animals and plants.</figcaption></figure> The modern concept of extraterrestrial life is based on assumptions that were not commonplace during the early days of <a href="/wiki/History_of_astronomy" title="History of astronomy">astronomy</a>. The first explanations for the celestial objects seen in the <a href="/wiki/Night_sky" title="Night sky">night sky</a> were based on mythology. Scholars from <a href="/wiki/Ancient_Greece" title="Ancient Greece">Ancient Greece</a> were the first to consider that the universe is inherently understandable and rejected explanations based on supernatural incomprehensible forces, such as the myth of the Sun being pulled across the sky in the chariot of <a href="/wiki/Apollo" title="Apollo">Apollo</a>. They had not developed the <a href="/wiki/Scientific_method" title="Scientific method">scientific method</a> yet and based their ideas on pure thought and speculation, but they developed precursor ideas to it, such as that explanations had to be discarded if they contradict observable facts. The discussions of those Greek scholars established many of the pillars that would eventually lead to the idea of extraterrestrial life, such as Earth being round and not flat. The cosmos was first structured in a <a href="/wiki/Geocentric_model" title="Geocentric model">geocentric model</a> that considered that the sun and all other celestial bodies revolve around Earth. However, they did not consider them as worlds. In Greek understanding, the world was composed by both Earth and the celestial objects with noticeable movements. <a href="/wiki/Anaximander" title="Anaximander">Anaximander</a> thought that the cosmos was made from apeiron, a substance that created the world, and that the world would eventually return to the cosmos. Eventually two groups emerged, the <a href="/wiki/Atomism" title="Atomism">atomists</a> that thought that matter at both Earth and the cosmos was equally made of small atoms of the <a href="/wiki/Classical_elements" class="mw-redirect" title="Classical elements">classical elements</a> (earth, water, fire and air), and the <a href="/wiki/Aristotelian_physics" title="Aristotelian physics">Aristotelians</a> who thought that those elements were exclusive of Earth and that the cosmos was made of a fifth one, the <a href="/wiki/Aether_(classical_element)" title="Aether (classical element)">aether</a>. Atomist <a href="/wiki/Epicurus" title="Epicurus">Epicurus</a> thought that the processes that created the world, its animals and plants should have created other worlds elsewhere, along with their own animals and plants. Aristotle thought instead that all the earth element naturally fell towards the center of the universe, and that would made it impossible for other planets to exist elsewhere. Under that reasoning, Earth was not only in the center, it was also the only planet in the universe.<a href="#cite_note-120">[116]</a> Cosmic pluralism, the plurality of worlds, or simply pluralism, describes the philosophical belief in numerous "worlds" in addition to Earth, which might harbor extraterrestrial life. The earliest recorded assertion of extraterrestrial human life is found in ancient scriptures of <a href="/wiki/Jainism" title="Jainism">Jainism</a>. There are multiple "worlds" mentioned in Jain scriptures that support human life. These include, among others, Bharat Kshetra, Mahavideh Kshetra, Airavat Kshetra, and Hari kshetra.<a href="#cite_note-crowe1999-121">[117]</a><a href="#cite_note-122">[118]</a><a href="#cite_note-Irwin-123">[119]</a> Medieval Muslim writers like <a href="/wiki/Fakhr_al-Din_al-Razi" title="Fakhr al-Din al-Razi">Fakhr al-Din al-Razi</a> and <a href="/wiki/Muhammad_al-Baqir" title="Muhammad al-Baqir">Muhammad al-Baqir</a> supported cosmic pluralism on the basis of the <a href="/wiki/Qur%27an" class="mw-redirect" title="Qur'an">Qur'an</a>.<a href="#cite_note-Weintraub-124">[120]</a> <a href="/wiki/Geoffrey_Chaucer" title="Geoffrey Chaucer">Chaucer</a>'s poem <a href="/wiki/The_House_of_Fame" title="The House of Fame">The House of Fame</a> engaged in medieval thought experiments that postulated the plurality of worlds.<a href="#cite_note-Gabrovsky_2016_p._83-125">[121]</a> However, those ideas about other worlds were different from the current knowledge about the structure of the universe, and did not postulate the existence of planetary systems other than the Solar System. When those authors talk about other worlds, they talk about places located at the center of their own systems, and with their own stellar vaults and cosmos surrounding them.<a href="#cite_note-126">[122]</a> The Greek ideas and the disputes between atomists and Aristotelians outlived the fall of the Greek empire. The <a href="/wiki/Great_Library_of_Alexandria" class="mw-redirect" title="Great Library of Alexandria">Great Library of Alexandria</a> compiled information about it, part of which was translated by Islamic scholars and thus survived the end of the Library. Baghdad combined the knowledge of the Greeks, the Indians, the Chinese and its own scholars, and the knowledge expanded through the <a href="/wiki/Byzantine_Empire" title="Byzantine Empire">Byzantine Empire</a>. From there it eventually returned to Europe by the time of the <a href="/wiki/Middle_Ages" title="Middle Ages">Middle Ages</a>. However, as the Greek atomist doctrine held that the world was created by random movements of atoms, with no need for a <a href="/wiki/Creator_deity" title="Creator deity">creator deity</a>, it became associated with <a href="/wiki/Atheism" title="Atheism">atheism</a>, and the dispute intertwined with religious ones.<a href="#cite_note-127">[123]</a> Still, the Church did not react to those topics in a homogeneous way, and there were stricter and more permissive views within the church itself.<a href="#cite_note-Bennet31-128">[124]</a> The first known mention of the term 'panspermia' was in the writings of the 5th-century BC <a href="/wiki/Ancient_Greece" title="Ancient Greece">Greek</a> philosopher <a href="/wiki/Anaxagoras" title="Anaxagoras">Anaxagoras</a>. He proposed the idea that life exists everywhere.<a href="#cite_note-Anaxagoras-129">[125]</a> <div class="mw-heading mw-heading3"><h3 id="Early_modern_period">Early modern period</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=12" title="Edit section: Early modern period">edit</a>]</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Galileo_before_the_Holy_Office_-_Joseph-Nicolas_Robert-Fleury,_1847.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6b/Galileo_before_the_Holy_Office_-_Joseph-Nicolas_Robert-Fleury%2C_1847.png/300px-Galileo_before_the_Holy_Office_-_Joseph-Nicolas_Robert-Fleury%2C_1847.png" decoding="async" width="300" height="190" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6b/Galileo_before_the_Holy_Office_-_Joseph-Nicolas_Robert-Fleury%2C_1847.png/450px-Galileo_before_the_Holy_Office_-_Joseph-Nicolas_Robert-Fleury%2C_1847.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6b/Galileo_before_the_Holy_Office_-_Joseph-Nicolas_Robert-Fleury%2C_1847.png/600px-Galileo_before_the_Holy_Office_-_Joseph-Nicolas_Robert-Fleury%2C_1847.png 2x" data-file-width="5425" data-file-height="3441" /></a><figcaption>Galileo before the Holy Office, a 19th-century painting by <a href="/wiki/Joseph-Nicolas_Robert-Fleury" title="Joseph-Nicolas Robert-Fleury">Joseph-Nicolas Robert-Fleury</a></figcaption></figure> By the time of the <a href="/wiki/Late_Middle_Ages" title="Late Middle Ages">late Middle Ages</a> there were many known inaccuracies in the geocentric model, but it was kept in use because <a href="/wiki/Naked_eye" title="Naked eye">naked eye</a> observations provided limited data. <a href="/wiki/Nicolaus_Copernicus" title="Nicolaus Copernicus">Nicolaus Copernicus</a> started the <a href="/wiki/Copernican_Revolution" title="Copernican Revolution">Copernican Revolution</a> by proposing that the planets revolve around the sun rather than Earth. His proposal had little acceptance at first because, as he kept the assumption that orbits were perfect circles, his model led to as many inaccuracies as the geocentric one. <a href="/wiki/Tycho_Brahe" title="Tycho Brahe">Tycho Brahe</a> improved the available data with naked-eye observatories, which worked with highly complex <a href="/wiki/Sextant" title="Sextant">sextants</a> and <a href="/wiki/Quadrant_(instrument)" title="Quadrant (instrument)">quadrants</a>. Tycho could not make sense of his observations, but <a href="/wiki/Johannes_Kepler" title="Johannes Kepler">Johannes Kepler</a> did: orbits were not perfect circles, but ellipses. This knowledge benefited the Copernican model, which worked now almost perfectly. The invention of the <a href="/wiki/Telescope" title="Telescope">telescope</a> a short time later, perfected by <a href="/wiki/Galileo_Galilei" title="Galileo Galilei">Galileo Galilei</a>, clarified the final doubts, and the <a href="/wiki/Paradigm_shift" title="Paradigm shift">paradigm shift</a> was completed.<a href="#cite_note-130">[126]</a> Under this new understanding, the notion of extraterrestrial life became feasible: if Earth is but just a planet orbiting around a star, there may be planets similar to Earth elsewhere. The astronomical study of distant bodies also proved that physical laws are the same elsewhere in the universe as on Earth, with nothing making the planet truly special.<a href="#cite_note-131">[127]</a> The new ideas were met with resistance from the Catholic church. Galileo was <a href="/wiki/Galileo_affair" title="Galileo affair">tried</a> for the heliocentric model, which was considered heretical, and forced to recant it.<a href="#cite_note-132">[128]</a> The best-known early-modern proponent of ideas of extraterrestrial life was the Italian philosopher <a href="/wiki/Giordano_Bruno" title="Giordano Bruno">Giordano Bruno</a>, who argued in the 16th century for an infinite universe in which every star is surrounded by its own <a href="/wiki/Planetary_system" title="Planetary system">planetary system</a>. Bruno wrote that other worlds "have no less virtue nor a nature different to that of our earth" and, like Earth, "contain animals and inhabitants".<a href="#cite_note-133">[129]</a> Bruno's belief in the plurality of worlds was one of the charges leveled against him by the <a href="/wiki/Venetian_Holy_Inquisition" title="Venetian Holy Inquisition">Venetian Holy Inquisition</a>, which trialed and executed him.<a href="#cite_note-AM8-134">[130]</a> The heliocentric model was further strengthened by the postulation of the <a href="/wiki/Theory_of_gravity" class="mw-redirect" title="Theory of gravity">theory of gravity</a> by Sir <a href="/wiki/Isaac_Newton" title="Isaac Newton">Isaac Newton</a>. This theory provided the mathematics that explains the motions of all things in the universe, including planetary orbits. By this point, the geocentric model was definitely discarded. By this time, the use of the scientific method had become a standard, and new discoveries were expected to provide evidence and rigorous mathematical explanations. Science also took a deeper interest in the mechanics of natural phenomena, trying to explain not just the way nature works but also the reasons for working that way.<a href="#cite_note-135">[131]</a> There was very little actual discussion about extraterrestrial life before this point, as the Aristotlean ideas remained influential while geocentrism was still accepted. When it was finally proved wrong, it not only meant that Earth was not the center of the universe, but also that the lights seen in the sky were not just lights, but physical objects. The notion that life may exist in them as well soon became an ongoing topic of discussion, although one with no practical ways to investigate.<a href="#cite_note-136">[132]</a> The possibility of extraterrestrials remained a widespread speculation as scientific discovery accelerated. <a href="/wiki/William_Herschel" title="William Herschel">William Herschel</a>, the discoverer of <a href="/wiki/Uranus" title="Uranus">Uranus</a>, was one of many 18th–19th-century astronomers who believed that the <a href="/wiki/Solar_System" title="Solar System">Solar System</a> is populated by alien life. Other scholars of the period who championed "cosmic pluralism" included <a href="/wiki/Immanuel_Kant" title="Immanuel Kant">Immanuel Kant</a> and <a href="/wiki/Benjamin_Franklin" title="Benjamin Franklin">Benjamin Franklin</a>. At the height of the <a href="/wiki/Age_of_Enlightenment" title="Age of Enlightenment">Enlightenment</a>, even the <a href="/wiki/Sun" title="Sun">Sun</a> and Moon were considered candidates for extraterrestrial inhabitants.<a href="#cite_note-137">[133]</a><a href="#cite_note-138">[134]</a> <div class="mw-heading mw-heading3"><h3 id="19th_century">19th century</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=13" title="Edit section: 19th century">edit</a>]</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Lowell_Mars_channels.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f3/Lowell_Mars_channels.jpg/220px-Lowell_Mars_channels.jpg" decoding="async" width="220" height="112" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f3/Lowell_Mars_channels.jpg/330px-Lowell_Mars_channels.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f3/Lowell_Mars_channels.jpg/440px-Lowell_Mars_channels.jpg 2x" data-file-width="800" data-file-height="409" /></a><figcaption>Artificial Martian channels, depicted by Percival Lowell</figcaption></figure> Speculation about life on Mars increased in the late 19th century, following telescopic observation of apparent <a href="/wiki/Martian_canals" title="Martian canals">Martian canals</a> – which soon, however, turned out to be optical illusions.<a href="#cite_note-139">[135]</a> Despite this, in 1895, American astronomer <a href="/wiki/Percival_Lowell" title="Percival Lowell">Percival Lowell</a> published his book Mars, followed by Mars and its Canals in 1906, proposing that the canals were the work of a long-gone civilisation.<a href="#cite_note-Wallace1907-140">[136]</a> <a href="/wiki/Spectroscopy" title="Spectroscopy">Spectroscopic</a> analysis of Mars's atmosphere began in earnest in 1894, when U.S. astronomer <a href="/wiki/William_Wallace_Campbell" title="William Wallace Campbell">William Wallace Campbell</a> showed that neither water nor oxygen was present in the <a href="/wiki/Martian_atmosphere" class="mw-redirect" title="Martian atmosphere">Martian atmosphere</a>.<a href="#cite_note-chambers-141">[137]</a> By 1909 better telescopes and the best perihelic opposition of Mars since 1877 conclusively put an end to the canal hypothesis.<a href="#cite_note-142">[138]</a> As a consequence of the belief in the <a href="/wiki/Spontaneous_generation" title="Spontaneous generation">spontaneous generation</a> there was little thought about the conditions of each celestial body: it was simply assumed that life would thrive anywhere. This theory was disproved by <a href="/wiki/Louis_Pasteur" title="Louis Pasteur">Louis Pasteur</a> in the 19th century. Popular belief in thriving alien civilisations elsewhere in the solar system still remained strong until <a href="/wiki/Mariner_4" title="Mariner 4">Mariner 4</a> and <a href="/wiki/Mariner_9" title="Mariner 9">Mariner 9</a> provided close images of Mars, which debunked forever the idea of the existence of Martians and decreased the previous expectations of finding alien life in general.<a href="#cite_note-143">[139]</a> The end of the spontaneous generation belief forced to investigate the origin of life. Although <a href="/wiki/Abiogenesis" title="Abiogenesis">abiogenesis</a> is the more accepted theory, a number of authors reclaimed the term "panspermia" and proposed that life was brought to Earth from elsewhere.<a href="#cite_note-Anaxagoras-129">[125]</a> Some of those authors are <a href="/wiki/J%C3%B6ns_Jacob_Berzelius" title="Jöns Jacob Berzelius">Jöns Jacob Berzelius</a> (1834),<a href="#cite_note-144">[140]</a> <a href="/wiki/William_Thomson,_1st_Baron_Kelvin" class="mw-redirect" title="William Thomson, 1st Baron Kelvin">Kelvin</a> (1871),<a href="#cite_note-145">[141]</a> <a href="/wiki/Hermann_von_Helmholtz" title="Hermann von Helmholtz">Hermann von Helmholtz</a> (1879)<a href="#cite_note-146">[142]</a> and, somewhat later, by <a href="/wiki/Svante_Arrhenius" title="Svante Arrhenius">Svante Arrhenius</a> (1903).<a href="#cite_note-147">[143]</a> The science fiction genre, although not so named during the time, developed during the late 19th century. The expansion of the genre of <a href="/wiki/Extraterrestrials_in_fiction" title="Extraterrestrials in fiction">extraterrestrials in fiction</a> influenced the popular perception over the real-life topic, making people eager to jump to conclusions about the discovery of aliens. Science marched at a slower pace, some discoveries fueled expectations and others dashed excessive hopes. For example, with the advent of telescopes, most structures seen on the Moon or Mars were immediately attributed to Selenites or Martians, and later ones (such as more powerful telescopes) revealed that all such discoveries were natural features.<a href="#cite_note-AM8-134">[130]</a> A famous case is the <a href="/wiki/Cydonia_(Mars)" title="Cydonia (Mars)">Cydonia</a> region of Mars, first imaged by the <a href="/wiki/Viking_1" title="Viking 1">Viking 1</a> orbiter. The low-resolution photos showed a rock formation that resembled a human face, but later spacecraft took photos in higher detail that showed that there was nothing special about the site.<a href="#cite_note-148">[144]</a> <div class="mw-heading mw-heading3"><h3 id="Recent_history">Recent history</h3>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=14" title="Edit section: Recent history">edit</a>]</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/Space_exploration" title="Space exploration">Space exploration</a></div> <style data-mw-deduplicate="TemplateStyles:r1237032888/mw-parser-output/.tmulti">.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmulti .multiimageinner img{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmulti .multiimageinner img{background-color:white}}</style><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:292px;max-width:292px"><div class="trow"><div class="tsingle" style="width:184px;max-width:184px"><div class="thumbimage" style="height:124px;overflow:hidden"><a href="/wiki/File:Telescope_Kepler-NASA.jpeg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Telescope_Kepler-NASA.jpeg/182px-Telescope_Kepler-NASA.jpeg" decoding="async" width="182" height="124" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Telescope_Kepler-NASA.jpeg/273px-Telescope_Kepler-NASA.jpeg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/83/Telescope_Kepler-NASA.jpeg/364px-Telescope_Kepler-NASA.jpeg 2x" data-file-width="864" data-file-height="591" /></a></div></div><div class="tsingle" style="width:104px;max-width:104px"><div class="thumbimage" style="height:124px;overflow:hidden"><a href="/wiki/File:C_G-K_-_DSC_0421.jpg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/C_G-K_-_DSC_0421.jpg/102px-C_G-K_-_DSC_0421.jpg" decoding="async" width="102" height="125" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/C_G-K_-_DSC_0421.jpg/153px-C_G-K_-_DSC_0421.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0c/C_G-K_-_DSC_0421.jpg/204px-C_G-K_-_DSC_0421.jpg 2x" data-file-width="408" data-file-height="500" /></a></div></div></div><div class="trow"><div class="tsingle" style="width:290px;max-width:290px"><div class="thumbimage" style="height:161px;overflow:hidden"><a href="/wiki/File:MSL_Sol_3070_-_MAHLI_(Version_2)_(51084526931).jpg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5d/MSL_Sol_3070_-_MAHLI_%28Version_2%29_%2851084526931%29.jpg/288px-MSL_Sol_3070_-_MAHLI_%28Version_2%29_%2851084526931%29.jpg" decoding="async" width="288" height="208" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5d/MSL_Sol_3070_-_MAHLI_%28Version_2%29_%2851084526931%29.jpg/432px-MSL_Sol_3070_-_MAHLI_%28Version_2%29_%2851084526931%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5d/MSL_Sol_3070_-_MAHLI_%28Version_2%29_%2851084526931%29.jpg/576px-MSL_Sol_3070_-_MAHLI_%28Version_2%29_%2851084526931%29.jpg 2x" data-file-width="8749" data-file-height="6313" /></a></div></div></div><div class="trow" style="display:flex"><div class="thumbcaption">Some major international efforts to search for extraterrestrial life, clockwise from top left: <ul><li>The search for <a href="/wiki/Extrasolar_planet" class="mw-redirect" title="Extrasolar planet">extrasolar planets</a> (image: <a href="/wiki/Kepler_space_telescope" title="Kepler space telescope">Kepler telescope</a>)</li> <li><a href="/wiki/SETI" class="mw-redirect" title="SETI">Listening for extraterrestrial signals indicating intelligence</a> (image: <a href="/wiki/Allen_Telescope_Array" title="Allen Telescope Array">Allen array</a>)</li> <li><a href="/wiki/Robotic_spacecraft" class="mw-redirect" title="Robotic spacecraft">Robotic exploration</a> of the <a href="/wiki/Solar_System" title="Solar System">Solar System</a> (image: <a href="/wiki/Curiosity_(rover)" title="Curiosity (rover)">Curiosity rover</a> on <a href="/wiki/Mars" title="Mars">Mars</a>)</li></ul></div></div></div></div> The search and study of extraterrestrial life became a science of its own, <a href="/wiki/Astrobiology" title="Astrobiology">astrobiology</a>. Also known as exobiology, this discipline is studied by the <a href="/wiki/NASA" title="NASA">NASA</a>, the <a href="/wiki/ESA" class="mw-redirect" title="ESA">ESA</a>, the <a href="/wiki/INAF" class="mw-redirect" title="INAF">INAF</a>, and others. Astrobiology studies life from Earth as well, but with a cosmic perspective. For example, <a href="/wiki/Abiogenesis" title="Abiogenesis">abiogenesis</a> is of interest to astrobiology, not because of the origin of life on Earth, but for the chances of a similar process taking place in other celestial bodies. Many aspects of life, from its definition to its chemistry, are analyzed as either likely to be similar in all forms of life across the cosmos or only native to Earth.<a href="#cite_note-149">[145]</a> Astrobiology, however, remains constrained by the current lack of extraterrestrial life-forms to study, as all life on Earth comes from the same ancestor, and it is hard to infer general characteristics from a group with a single example to analyse.<a href="#cite_note-150">[146]</a> The 20th century came with great technological advances, speculations about future <a href="/wiki/Hypothetical_technology" title="Hypothetical technology">hypothetical technologies</a>, and an increased basic knowledge of science by the general population thanks to <a href="/wiki/Science_divulgation" class="mw-redirect" title="Science divulgation">science divulgation</a> through the mass media. The public interest in extraterrestrial life and the lack of discoveries by mainstream science led to the emergence of <a href="/wiki/Pseudoscience" title="Pseudoscience">pseudosciences</a> that provided affirmative, if questionable, answers to the existence of aliens. <a href="/wiki/Ufology" title="Ufology">Ufology</a> claims that many <a href="/wiki/Unidentified_flying_object" title="Unidentified flying object">unidentified flying objects</a> (UFOs) would be spaceships from alien species, and <a href="/wiki/Ancient_astronauts" title="Ancient astronauts">ancient astronauts</a> hypothesis claim that aliens would have visited Earth in antiquity and prehistoric times but people would have failed to understand it by then.<a href="#cite_note-151">[147]</a> Most UFOs or <a href="/wiki/List_of_UFO_sightings" class="mw-redirect" title="List of UFO sightings">UFO sightings</a><a href="#cite_note-152">[148]</a> can be readily explained as sightings of Earth-based aircraft (including <a href="/wiki/Black_project" title="Black project">top-secret aircraft</a>), known <a href="/wiki/Astronomical_object" title="Astronomical object">astronomical objects</a> or weather phenomenons, or as <a href="/wiki/Hoax" title="Hoax">hoaxes</a>.<a href="#cite_note-153">[149]</a> Looking beyond the pseudosciences, <a href="/wiki/Lewis_White_Beck" title="Lewis White Beck">Lewis White Beck</a> strove to elevate the level of public discourse on the topic of extraterrestrial life by tracing the evolution of philosophical thought over the centuries from ancient times into the modern era. His review of the contributions made by <a href="/wiki/Lucretius" title="Lucretius">Lucretius</a>, <a href="/wiki/Plutarch" title="Plutarch">Plutarch</a>, <a href="/wiki/Aristotle" title="Aristotle">Aristotle</a>, <a href="/wiki/Copernicus" class="mw-redirect" title="Copernicus">Copernicus</a>, <a href="/wiki/Immanuel_Kant" title="Immanuel Kant">Immanuel Kant</a>, <a href="/wiki/Thomas_Wilkins" class="mw-disambig" title="Thomas Wilkins">Thomas Wilkins</a>, <a href="/wiki/Charles_Darwin" title="Charles Darwin">Charles Darwin</a> and <a href="/wiki/Karl_Marx" title="Karl Marx">Karl Marx</a> demonstrated that even in modern times, humanity could be profoundly influenced in its search for extraterrestrial life by subtle and comforting archetypal ideas which are largely derived from firmly held religious, philosophical and existential belief systems. On a positive note, however, Beck further argued that even if the search for extraterrestrial life proves to be unsuccessful, the endeavor itself could have beneficial consequences by assisting humanity in its attempt to actualize superior ways of living here on Earth.<a href="#cite_note-154">[150]</a> By the 21st century, it was accepted that multicellular life in the Solar System can only exist on Earth, but the interest in extraterrestrial life increased regardless. This is a result of the advances in several sciences. The knowledge of planetary habitability allows to consider on scientific terms the likelihood of finding life at each specific celestial body, as it is known which features are beneficial and harmful for life. Astronomy and telescopes also improved to the point exoplanets can be confirmed and even studied, increasing the number of search places. Life may still exist elsewhere in the Solar System in unicellular form, but the advances in spacecraft allow to send robots to study samples in situ, with tools of growing complexity and reliability. Although no extraterrestrial life has been found and life may still be just a rarity from Earth, there are scientific reasons to suspect that it can exist elsewhere, and technological advances that may detect it if it does.<a href="#cite_note-155">[151]</a> Many scientists are optimistic about the chances of finding alien life. In the words of SETI's Frank Drake, "All we know for sure is that the sky is not littered with powerful microwave transmitters".<a href="#cite_note-156">[152]</a> Drake noted that it is entirely possible that advanced technology results in communication being carried out in some way other than conventional radio transmission. At the same time, the data returned by space probes, and giant strides in detection methods, have allowed science to begin delineating <a href="/wiki/Planetary_habitability" title="Planetary habitability">habitability criteria</a> on other worlds, and to confirm that at least other planets are plentiful, though aliens remain a question mark. The <a href="/wiki/Wow!_signal" title="Wow! signal">Wow! signal</a>, detected in 1977 by a SETI project, remains a subject of speculative debate.<a href="#cite_note-157">[153]</a> On the other hand, other scientists are pessimistic. Jacques Monod wrote that "Man knows at last that he is alone in the indifferent immensity of the universe, whence which he has emerged by chance".<a href="#cite_note-158">[154]</a> In 2000, geologist and <a href="/wiki/Paleontologist" class="mw-redirect" title="Paleontologist">paleontologist</a> <a href="/wiki/Peter_Ward_(paleontologist)" title="Peter Ward (paleontologist)">Peter Ward</a> and <a href="/wiki/Astrobiology" title="Astrobiology">astrobiologist</a> <a href="/wiki/Donald_Brownlee" class="mw-redirect" title="Donald Brownlee">Donald Brownlee</a> published a book entitled <a href="/wiki/Rare_Earth_(book)" class="mw-redirect" title="Rare Earth (book)">Rare Earth: Why Complex Life is Uncommon in the Universe</a>.<a href="#cite_note-159">[155]</a>[<a href="/wiki/Wikipedia:NOTRS" class="mw-redirect" title="Wikipedia:NOTRS">better source needed</a>] In it, they discussed the <a href="/wiki/Rare_Earth_hypothesis" title="Rare Earth hypothesis">Rare Earth hypothesis</a>, in which they claim that Earth-like life is rare in the <a href="/wiki/Universe" title="Universe">universe</a>, whereas <a href="/wiki/Bacteria" title="Bacteria">microbial</a> life is common. Ward and Brownlee are open to the idea of evolution on other planets that is not based on essential Earth-like characteristics such as DNA and carbon. As for the possible risks, theoretical physicist <a href="/wiki/Stephen_Hawking" title="Stephen Hawking">Stephen Hawking</a> warned in 2010 that humans should not try to contact alien life forms. He warned that aliens might pillage Earth for resources. "If aliens visit us, the outcome would be much as when <a href="/wiki/Christopher_Columbus" title="Christopher Columbus">Columbus</a> landed in <a href="/wiki/Americas" title="Americas">America</a>, which didn't turn out well for the <a href="/wiki/Indigenous_peoples_of_the_Americas" title="Indigenous peoples of the Americas">Native Americans</a>", he said.<a href="#cite_note-160">[156]</a> <a href="/wiki/Jared_Diamond" title="Jared Diamond">Jared Diamond</a> had earlier expressed similar concerns.<a href="#cite_note-161">[157]</a> On 20 July 2015, Hawking and Russian billionaire <a href="/wiki/Yuri_Milner" title="Yuri Milner">Yuri Milner</a>, along with the <a href="/wiki/SETI_Institute" title="SETI Institute">SETI Institute</a>, announced a well-funded effort, called the <a href="/wiki/Breakthrough_Initiatives" title="Breakthrough Initiatives">Breakthrough Initiatives</a>, to expand efforts to search for extraterrestrial life. The group contracted the services of the 100-meter <a href="/wiki/Robert_C._Byrd" class="mw-redirect" title="Robert C. Byrd">Robert C. Byrd</a> <a href="/wiki/Green_Bank_Telescope" title="Green Bank Telescope">Green Bank Telescope</a> in West Virginia in the United States and the 64-meter <a href="/wiki/Parkes_Telescope" class="mw-redirect" title="Parkes Telescope">Parkes Telescope</a> in New South Wales, Australia.<a href="#cite_note-AP-20150720-162">[158]</a> On 13 February 2015, scientists (including <a href="/wiki/Geoffrey_Marcy" title="Geoffrey Marcy">Geoffrey Marcy</a>, <a href="/wiki/Seth_Shostak" title="Seth Shostak">Seth Shostak</a>, <a href="/wiki/Frank_Drake" title="Frank Drake">Frank Drake</a> and <a href="/wiki/David_Brin" title="David Brin">David Brin</a>) at a convention of the <a href="/wiki/American_Association_for_the_Advancement_of_Science" title="American Association for the Advancement of Science">American Association for the Advancement of Science</a>, discussed <a href="/wiki/Active_SETI" title="Active SETI">Active SETI</a> and whether transmitting a message to possible intelligent extraterrestrials in the <a href="/wiki/Cosmos" title="Cosmos">Cosmos</a> was a good idea;<a href="#cite_note-NYT-20150213-163">[159]</a><a href="#cite_note-BBC-20150212-164">[160]</a> one result was a statement, signed by many, that a "worldwide scientific, political and humanitarian discussion must occur before any message is sent".<a href="#cite_note-UCB-20150213-165">[161]</a> <div class="mw-heading mw-heading2"><h2 id="Government_responses">Government responses</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=15" title="Edit section: Government responses">edit</a>]</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/Planetary_protection" title="Planetary protection">Planetary protection</a></div> The 1967 <a href="/wiki/Outer_Space_Treaty" title="Outer Space Treaty">Outer Space Treaty</a> and the 1979 <a href="/wiki/Moon_Agreement" class="mw-redirect" title="Moon Agreement">Moon Agreement</a> define rules of <a href="/wiki/Planetary_protection" title="Planetary protection">planetary protection</a> against potentially hazardous extraterrestrial life. <a href="/wiki/COSPAR" class="mw-redirect" title="COSPAR">COSPAR</a> also provides guidelines for planetary protection.<a href="#cite_note-166">[162]</a> A committee of the <a href="/wiki/United_Nations_Office_for_Outer_Space_Affairs" title="United Nations Office for Outer Space Affairs">United Nations Office for Outer Space Affairs</a> had in 1977 discussed for a year strategies for interacting with extraterrestrial life or intelligence. The discussion ended without any conclusions. As of 2010, the UN lacks response mechanisms for the case of an extraterrestrial contact.<a href="#cite_note-167">[163]</a> One of the NASA divisions is the Office of Safety and Mission Assurance (OSMA), also known as the Planetary Protection Office. A part of its mission is to "rigorously preclude backward contamination of Earth by extraterrestrial life."<a href="#cite_note-168">[164]</a> In 2016, the Chinese Government released a white paper detailing its <a href="/wiki/Chinese_Space_Program" class="mw-redirect" title="Chinese Space Program">space program</a>. According to the document, one of the research objectives of the program is the search for extraterrestrial life.<a href="#cite_note-169">[165]</a> It is also one of the objectives of the Chinese <a href="/wiki/Five-hundred-meter_Aperture_Spherical_Telescope" title="Five-hundred-meter Aperture Spherical Telescope">Five-hundred-meter Aperture Spherical Telescope</a> (FAST) program.<a href="#cite_note-170">[166]</a> In 2020, <a href="/wiki/Dmitry_Rogozin" title="Dmitry Rogozin">Dmitry Rogozin</a>, the head of the <a href="/wiki/Roskosmos" class="mw-redirect" title="Roskosmos">Russian space agency</a>, said the search for extraterrestrial life is one of the main goals of deep space research. He also acknowledged the possibility of existence of primitive life on other planets of the Solar System.<a href="#cite_note-171">[167]</a> The <a href="/wiki/CNES" title="CNES">French space agency</a> has an office for the study of "non-identified aero spatial phenomena".<a href="#cite_note-newscientist.com-172">[168]</a><a href="#cite_note-173">[169]</a> The agency is maintaining a publicly accessible database of such phenomena, with over 1600 detailed entries. According to the head of the office, the vast majority of entries have a mundane explanation; but for 25% of entries, their extraterrestrial origin can neither be confirmed nor denied.<a href="#cite_note-newscientist.com-172">[168]</a> In 2020, chairman of the <a href="/wiki/Israel_Space_Agency" title="Israel Space Agency">Israel Space Agency</a> <a href="/wiki/Isaac_Ben-Israel" title="Isaac Ben-Israel">Isaac Ben-Israel</a> stated that the probability of detecting life in outer space is "quite large". But he disagrees with his former colleague <a href="/wiki/Haim_Eshed" title="Haim Eshed">Haim Eshed</a> who stated that there are contacts between an advanced alien civilisation and some of Earth's governments.<a href="#cite_note-174">[170]</a> <div class="mw-heading mw-heading2"><h2 id="In_fiction">In fiction</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=16" title="Edit section: In fiction">edit</a>]</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/Extraterrestrials_in_fiction" title="Extraterrestrials in fiction">Extraterrestrials in fiction</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Grey_Aliens_Drawing.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Grey_Aliens_Drawing.jpg/220px-Grey_Aliens_Drawing.jpg" decoding="async" width="220" height="143" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Grey_Aliens_Drawing.jpg/330px-Grey_Aliens_Drawing.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Grey_Aliens_Drawing.jpg/440px-Grey_Aliens_Drawing.jpg 2x" data-file-width="3393" data-file-height="2204" /></a><figcaption><a href="/wiki/Grey_alien" title="Grey alien">Grey aliens</a> are a common way to depict extraterrestrials in fiction.</figcaption></figure> Although the idea of extraterrestrial peoples became feasible once astronomy developed enough to understand the nature of planets, they were not thought of as being any different from humans. Having no scientific explanation for the <a href="/wiki/Origin_of_mankind" class="mw-redirect" title="Origin of mankind">origin of mankind</a> and its relation to other species, there was no reason to expect them to be any other way. This was changed by the 1859 book <a href="/wiki/On_the_Origin_of_Species" title="On the Origin of Species">On the Origin of Species</a> by <a href="/wiki/Charles_Darwin" title="Charles Darwin">Charles Darwin</a>, which proposed the <a href="/wiki/Theory_of_evolution" class="mw-redirect" title="Theory of evolution">theory of evolution</a>. Now with the notion that evolution on other planets may take other directions, <a href="/wiki/Science_fiction" title="Science fiction">science fiction</a> authors created bizarre aliens, clearly distinct from humans. A usual way to do that was to add body features from other animals, such as insects or octopuses. Costuming and special effects feasibility alongside budget considerations forced films and TV series to tone down the fantasy, but these limitations lessened since the 1990s with the advent of <a href="/wiki/Computer-generated_imagery" title="Computer-generated imagery">computer-generated imagery</a> (CGI), and later on as CGI became more effective and less expensive.<a href="#cite_note-early-175">[171]</a> Real-life events sometimes captivate people's imagination and this influences the works of fiction. For example, during the <a href="/wiki/Barney_and_Betty_Hill_incident" title="Barney and Betty Hill incident">Barney and Betty Hill incident</a>, the first recorded claim of an <a href="/wiki/Alien_abduction" title="Alien abduction">alien abduction</a>, the couple reported that they were abducted and experimented on by aliens with oversized heads, big eyes, pale grey skin, and small noses, a description that eventually became the <a href="/wiki/Grey_alien" title="Grey alien">grey alien</a> archetype once used in works of fiction.<a href="#cite_note-early-175">[171]</a> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=17" title="Edit section: See also">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col 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: 30em;"> <ul><li><a href="/wiki/Assembly_theory" title="Assembly theory">Assembly theory</a></li> <li><a href="/wiki/Carbon_chauvinism" title="Carbon chauvinism">Carbon chauvinism</a></li> <li><a href="/wiki/First_contact_(anthropology)" title="First contact (anthropology)">First contact (anthropology)</a></li> <li><a href="/wiki/Hemolithin" title="Hemolithin">Hemolithin</a></li> <li><a href="/wiki/Hypothetical_types_of_biochemistry" title="Hypothetical types of biochemistry">Hypothetical types of biochemistry</a></li> <li><a href="/wiki/Life_origination_beyond_planets" title="Life origination beyond planets">Life origination beyond planets</a></li> <li><a href="/wiki/Outline_of_extraterrestrial_life" title="Outline of extraterrestrial life">Outline of extraterrestrial life</a></li> <li><a href="/wiki/Quiet_and_loud_aliens" title="Quiet and loud aliens">Quiet and loud aliens</a></li> <li><a href="/wiki/Sentiocentrism" class="mw-redirect" title="Sentiocentrism">Sentiocentrism</a></li> <li><a href="/wiki/Speciesism" title="Speciesism">Speciesism</a></li> <li><a href="/wiki/Uncontacted_peoples" title="Uncontacted peoples">Uncontacted peoples</a></li></ul></div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=18" title="Edit section: Notes">edit</a>]</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-lower-alpha"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-footnoteA-108"><a href="#cite_ref-footnoteA_108-0">^</a> For the purpose of this 1 in 5 statistic, "Sun-like" means <a href="/wiki/G-type_main-sequence_star" title="G-type main-sequence star">G-type star</a>. Data for Sun-like stars wasn't available so this statistic is an extrapolation from data about <a href="/wiki/K-type_main-sequence_star" title="K-type main-sequence star">K-type stars</a> </li> <li id="cite_note-footnoteB-109"><a href="#cite_ref-footnoteB_109-0">^</a> For the purpose of this 1 in 5 statistic, Earth-sized means 1–2 Earth radii </li> <li id="cite_note-footnoteC-110"><a href="#cite_ref-footnoteC_110-0">^</a> For the purpose of this 1 in 5 statistic, "habitable zone" means the region with 0.25 to 4 times Earth's stellar flux (corresponding to 0.5–2 AU for the Sun). </li> <li id="cite_note-footnoteD-113"><a href="#cite_ref-footnoteD_113-0">^</a> About 1/4 of stars are GK Sun-like stars. The number of stars in the galaxy is not accurately known, but assuming 200 billion stars in total, the Milky Way would have about 50 billion Sun-like (GK) stars, of which about 1 in 5 (22%) or 11 billion would be Earth-sized in the habitable zone. Including red dwarfs would increase this to 40 billion. </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=19" title="Edit section: References">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-WP-20201231-1"><a href="#cite_ref-WP-20201231_1-0">^</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="CITEREFFrank2020" class="citation news cs1">Frank, Adam (31 December 2020). <a rel="nofollow" class="external text" href="https://www.washingtonpost.com/outlook/2020/12/31/breakthrough-listen-seti-technosignatures/">"A new frontier is opening in the search for extraterrestrial life – The reason we haven't found life elsewhere in the universe is simple: We haven't really looked until now"</a>. <a href="/wiki/The_Washington_Post" title="The Washington Post">The Washington Post</a>. Retrieved 1 January 2021.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Washington+Post&rft.atitle=A+new+frontier+is+opening+in+the+search+for+extraterrestrial+life+%E2%80%93+The+reason+we+haven%27t+found+life+elsewhere+in+the+universe+is+simple%3A+We+haven%27t+really+looked+until+now.&rft.date=2020-12-31&rft.aulast=Frank&rft.aufirst=Adam&rft_id=https%3A%2F%2Fwww.washingtonpost.com%2Foutlook%2F2020%2F12%2F31%2Fbreakthrough-listen-seti-technosignatures%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NYT-20131118-2"><a href="#cite_ref-NYT-20131118_2-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDavies2013" class="citation news cs1"><a href="/wiki/Paul_Davies" title="Paul Davies">Davies, Paul</a> (18 November 2013). <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2013/11/19/opinion/are-we-alone-in-the-universe.html">"Are We Alone in the Universe?"</a>. <a href="/wiki/The_New_York_Times" title="The New York Times">The New York Times</a>. Archived from <a rel="nofollow" class="external text" href="https://www.nytimes.com/2013/11/19/opinion/are-we-alone-in-the-universe.html">the original</a> on 1 January 2022. Retrieved 20 November 2013.</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=Are+We+Alone+in+the+Universe%3F&rft.date=2013-11-18&rft.aulast=Davies&rft.aufirst=Paul&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2013%2F11%2F19%2Fopinion%2Fare-we-alone-in-the-universe.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-3"><a href="#cite_ref-3">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPickrell2006" class="citation news cs1">Pickrell, John (4 September 2006). <a rel="nofollow" class="external text" href="https://www.newscientist.com/article/dn9943-top-10-controversial-pieces-of-evidence-for-extraterrestrial-life.html">"Top 10: Controversial pieces of evidence for extraterrestrial life"</a>. <a href="/wiki/New_Scientist" title="New Scientist">New Scientist</a>. Retrieved 18 February 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=New+Scientist&rft.atitle=Top+10%3A+Controversial+pieces+of+evidence+for+extraterrestrial+life&rft.date=2006-09-04&rft.aulast=Pickrell&rft.aufirst=John&rft_id=https%3A%2F%2Fwww.newscientist.com%2Farticle%2Fdn9943-top-10-controversial-pieces-of-evidence-for-extraterrestrial-life.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-4"><a href="#cite_ref-4">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrowe2008" class="citation book cs1">Crowe, Michael J. (2008). The extraterrestrial life debate, antiquity to 1915: a source book/edited by Michael J. Crowe. University of Notre Dame. pp. 14–16.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+extraterrestrial+life+debate%2C+antiquity+to+1915%3A+a+source+book%2Fedited+by+Michael+J.+Crowe&rft.pages=14-16&rft.pub=University+of+Notre+Dame&rft.date=2008&rft.aulast=Crowe&rft.aufirst=Michael+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-5"><a href="#cite_ref-5">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrowe2008" class="citation book cs1">Crowe, Michael J. (2008). The extraterrestrial life debate, antiquity to 1915: a source book/edited by Michael J. Crowe. University of Notre Dame. pp. 26–27.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+extraterrestrial+life+debate%2C+antiquity+to+1915%3A+a+source+book%2Fedited+by+Michael+J.+Crowe&rft.pages=26-27&rft.pub=University+of+Notre+Dame&rft.date=2008&rft.aulast=Crowe&rft.aufirst=Michael+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-6"><a href="#cite_ref-6">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNicholas_of_Cusa.1954" class="citation book cs1">Nicholas of Cusa. (1954). Of Learned Ignorance. Translated by Germain Heron. Routledge. pp. 111–118.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Of+Learned+Ignorance&rft.pages=111-118&rft.pub=Routledge&rft.date=1954&rft.au=Nicholas+of+Cusa.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFCrowe2008" class="citation book cs1">Crowe, Michael J. (2008). The extraterrestrial life debate, antiquity to 1915: a source book/edited by Michael J. Crowe. University of Notre Dame. p. 67.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+extraterrestrial+life+debate%2C+antiquity+to+1915%3A+a+source+book%2Fedited+by+Michael+J.+Crowe&rft.pages=67&rft.pub=University+of+Notre+Dame&rft.date=2008&rft.aulast=Crowe&rft.aufirst=Michael+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </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="CITEREFCatling2015" class="citation cs2">Catling, D.C. (2015), <a rel="nofollow" class="external text" href="https://linkinghub.elsevier.com/retrieve/pii/B9780444538024001858">"Planetary Atmospheres"</a>, Treatise on Geophysics, Elsevier, pp. 429–472, <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/2015trge.book..429C">2015trge.book..429C</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%2Fb978-0-444-53802-4.00185-8">10.1016/b978-0-444-53802-4.00185-8</a>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-444-53803-1" title="Special:BookSources/978-0-444-53803-1"><bdi>978-0-444-53803-1</bdi></a>, retrieved 17 April 2024</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Treatise+on+Geophysics&rft.atitle=Planetary+Atmospheres&rft.pages=429-472&rft.date=2015&rft_id=info%3Adoi%2F10.1016%2Fb978-0-444-53802-4.00185-8&rft_id=info%3Abibcode%2F2015trge.book..429C&rft.isbn=978-0-444-53803-1&rft.aulast=Catling&rft.aufirst=D.C.&rft_id=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FB9780444538024001858&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-:0-9">^ <a href="#cite_ref-:0_9-0">a</a> <a href="#cite_ref-:0_9-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFShibuyaTakai2022" class="citation journal cs1">Shibuya, Takazo; Takai, Ken (16 November 2022). <a rel="nofollow" class="external text" href="https://doi.org/10.1186%2Fs40645-022-00510-6">"Liquid and supercritical CO2 as an organic solvent in Hadean seafloor hydrothermal systems: implications for prebiotic chemical evolution"</a>. Progress in Earth and Planetary Science. 9 (1). <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1186%2Fs40645-022-00510-6">10.1186/s40645-022-00510-6</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/2197-4284">2197-4284</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Progress+in+Earth+and+Planetary+Science&rft.atitle=Liquid+and+supercritical+CO2+as+an+organic+solvent+in+Hadean+seafloor+hydrothermal+systems%3A+implications+for+prebiotic+chemical+evolution&rft.volume=9&rft.issue=1&rft.date=2022-11-16&rft_id=info%3Adoi%2F10.1186%2Fs40645-022-00510-6&rft.issn=2197-4284&rft.aulast=Shibuya&rft.aufirst=Takazo&rft.au=Takai%2C+Ken&rft_id=https%3A%2F%2Fdoi.org%2F10.1186%252Fs40645-022-00510-6&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFDamerDeamer2020" class="citation journal cs1">Damer, Bruce; Deamer, David (1 April 2020). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7133448">"The Hot Spring Hypothesis for an Origin of Life"</a>. Astrobiology. 20 (4): 429–452. <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/2020AsBio..20..429D">2020AsBio..20..429D</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1089%2Fast.2019.2045">10.1089/ast.2019.2045</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/1531-1074">1531-1074</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7133448">7133448</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/31841362">31841362</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astrobiology&rft.atitle=The+Hot+Spring+Hypothesis+for+an+Origin+of+Life&rft.volume=20&rft.issue=4&rft.pages=429-452&rft.date=2020-04-01&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC7133448%23id-name%3DPMC&rft_id=info%3Abibcode%2F2020AsBio..20..429D&rft_id=info%3Apmid%2F31841362&rft_id=info%3Adoi%2F10.1089%2Fast.2019.2045&rft.issn=1531-1074&rft.aulast=Damer&rft.aufirst=Bruce&rft.au=Deamer%2C+David&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC7133448&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-11"><a href="#cite_ref-11">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMapelliMarascoRolliDaffonchio2015" class="citation cs2">Mapelli, Francesca; Marasco, Ramona; Rolli, Eleonora; Daffonchio, Daniele; Donachie, Stuart; Borin, Sara (2015), Rouwet, Dmitri; Christenson, Bruce; Tassi, Franco; Vandemeulebrouck, Jean (eds.), <a rel="nofollow" class="external text" href="http://link.springer.com/10.1007/978-3-642-36833-2_23">"Microbial Life in Volcanic Lakes"</a>, Volcanic Lakes, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 507–522, <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%2F978-3-642-36833-2_23">10.1007/978-3-642-36833-2_23</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/2434%2F266460">2434/266460</a>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-642-36832-5" title="Special:BookSources/978-3-642-36832-5"><bdi>978-3-642-36832-5</bdi></a>, retrieved 17 April 2024</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Volcanic+Lakes&rft.atitle=Microbial+Life+in+Volcanic+Lakes&rft.pages=507-522&rft.date=2015&rft_id=info%3Ahdl%2F2434%2F266460&rft_id=info%3Adoi%2F10.1007%2F978-3-642-36833-2_23&rft.isbn=978-3-642-36832-5&rft.aulast=Mapelli&rft.aufirst=Francesca&rft.au=Marasco%2C+Ramona&rft.au=Rolli%2C+Eleonora&rft.au=Daffonchio%2C+Daniele&rft.au=Donachie%2C+Stuart&rft.au=Borin%2C+Sara&rft_id=http%3A%2F%2Flink.springer.com%2F10.1007%2F978-3-642-36833-2_23&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NYT-20150106-DB-12">^ <a href="#cite_ref-NYT-20150106-DB_12-0">a</a> <a href="#cite_ref-NYT-20150106-DB_12-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOverbye2015" class="citation news cs1"><a href="/wiki/Dennis_Overbye" title="Dennis Overbye">Overbye, Dennis</a> (6 January 2015). <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2015/01/07/science/space/as-ranks-of-goldilocks-planets-grow-astronomers-consider-whats-next.html">"So Many Earth-Like Planets, So Few Telescopes"</a>. <a href="/wiki/The_New_York_Times" title="The New York Times">The New York Times</a>. Archived from <a rel="nofollow" class="external text" href="https://www.nytimes.com/2015/01/07/science/space/as-ranks-of-goldilocks-planets-grow-astronomers-consider-whats-next.html">the original</a> on 1 January 2022. Retrieved 6 January 2015.</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=So+Many+Earth-Like+Planets%2C+So+Few+Telescopes&rft.date=2015-01-06&rft.aulast=Overbye&rft.aufirst=Dennis&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2015%2F01%2F07%2Fscience%2Fspace%2Fas-ranks-of-goldilocks-planets-grow-astronomers-consider-whats-next.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-13"><a href="#cite_ref-13">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMann2020" class="citation web cs1">Mann, Adam (1 December 2020). <a rel="nofollow" class="external text" href="https://www.scientificamerican.com/article/want-to-talk-to-aliens-try-changing-the-technological-channel-beyond-radio/">"Want to Talk to Aliens? Try Changing the Technological Channel beyond Radio"</a>. Scientific American. Retrieved 10 May 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Scientific+American&rft.atitle=Want+to+Talk+to+Aliens%3F+Try+Changing+the+Technological+Channel+beyond+Radio&rft.date=2020-12-01&rft.aulast=Mann&rft.aufirst=Adam&rft_id=https%3A%2F%2Fwww.scientificamerican.com%2Farticle%2Fwant-to-talk-to-aliens-try-changing-the-technological-channel-beyond-radio%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </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="CITEREFGhosh2015" class="citation news cs1">Ghosh, Pallab (12 February 2015). <a rel="nofollow" class="external text" href="https://www.bbc.com/news/science-environment-31442952">"Scientists in US are urged to seek contact with aliens"</a>. BBC News.</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=Scientists+in+US+are+urged+to+seek+contact+with+aliens&rft.date=2015-02-12&rft.aulast=Ghosh&rft.aufirst=Pallab&rft_id=http%3A%2F%2Fwww.bbc.com%2Fnews%2Fscience-environment-31442952&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-15"><a href="#cite_ref-15">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBaumHaqq-MisraDomagal-Goldman2011" class="citation journal cs1">Baum, Seth; Haqq-Misra, Jacob; Domagal-Goldman, Shawn (June 2011). "Would Contact with Extraterrestrials Benefit or Harm Humanity? A Scenario Analysis". Acta Astronautica. 68 (11): 2114–2129. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1104.4462">1104.4462</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/2011AcAau..68.2114B">2011AcAau..68.2114B</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%2Fj.actaastro.2010.10.012">10.1016/j.actaastro.2010.10.012</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/0094-5765">0094-5765</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:16889489">16889489</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Astronautica&rft.atitle=Would+Contact+with+Extraterrestrials+Benefit+or+Harm+Humanity%3F+A+Scenario+Analysis&rft.volume=68&rft.issue=11&rft.pages=2114-2129&rft.date=2011-06&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A16889489%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2011AcAau..68.2114B&rft_id=info%3Aarxiv%2F1104.4462&rft.issn=0094-5765&rft_id=info%3Adoi%2F10.1016%2Fj.actaastro.2010.10.012&rft.aulast=Baum&rft.aufirst=Seth&rft.au=Haqq-Misra%2C+Jacob&rft.au=Domagal-Goldman%2C+Shawn&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-16"><a href="#cite_ref-16">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAvi_Loeb2021" class="citation web cs1">Avi Loeb (4 April 2021). <a rel="nofollow" class="external text" href="https://www.scientificamerican.com/article/when-did-life-first-emerge-in-the-universe/">"When Did Life First Emerge in the Universe?"</a>. Scientific American. Retrieved 17 April 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=When+Did+Life+First+Emerge+in+the+Universe%3F&rft.pub=Scientific+American&rft.date=2021-04-04&rft.au=Avi+Loeb&rft_id=https%3A%2F%2Fwww.scientificamerican.com%2Farticle%2Fwhen-did-life-first-emerge-in-the-universe%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-17"><a href="#cite_ref-17">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMoskowitz2012" class="citation web cs1"><a href="/wiki/Clara_Moskowitz" title="Clara Moskowitz">Moskowitz, Clara</a> (29 March 2012). <a rel="nofollow" class="external text" href="http://www.space.com/15089-life-building-blocks-young-sun-dust.html">"Life's Building Blocks May Have Formed in Dust Around Young Sun"</a>. <a href="/wiki/Space.com" title="Space.com">Space.com</a>. Retrieved 30 March 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Life%27s+Building+Blocks+May+Have+Formed+in+Dust+Around+Young+Sun&rft.pub=Space.com&rft.date=2012-03-29&rft.aulast=Moskowitz&rft.aufirst=Clara&rft_id=http%3A%2F%2Fwww.space.com%2F15089-life-building-blocks-young-sun-dust.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-USRA-2010-18"><a href="#cite_ref-USRA-2010_18-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRampelotto2010" class="citation conference cs1">Rampelotto, P. H. (April 2010). <a rel="nofollow" class="external text" href="http://www.lpi.usra.edu/meetings/abscicon2010/pdf/5224.pdf">Panspermia: A Promising Field of Research</a> (PDF). Astrobiology Science Conference 2010: Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond. 20–26 April 2010. League City, Texas. <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/2010LPICo1538.5224R">2010LPICo1538.5224R</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=Panspermia%3A+A+Promising+Field+of+Research&rft.date=2010-04&rft_id=info%3Abibcode%2F2010LPICo1538.5224R&rft.aulast=Rampelotto&rft.aufirst=P.+H.&rft_id=http%3A%2F%2Fwww.lpi.usra.edu%2Fmeetings%2Fabscicon2010%2Fpdf%2F5224.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-19"><a href="#cite_ref-19">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGonzalezRichards2004" class="citation book cs1">Gonzalez, Guillermo; Richards, Jay Wesley (2004). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=KFdu4CyQ1k0C&pg=PA343">The privileged planet: how our place in the cosmos is designed for discovery</a>. Regnery Publishing. pp. 343–345. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-89526-065-9" title="Special:BookSources/978-0-89526-065-9"><bdi>978-0-89526-065-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+privileged+planet%3A+how+our+place+in+the+cosmos+is+designed+for+discovery&rft.pages=343-345&rft.pub=Regnery+Publishing&rft.date=2004&rft.isbn=978-0-89526-065-9&rft.aulast=Gonzalez&rft.aufirst=Guillermo&rft.au=Richards%2C+Jay+Wesley&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DKFdu4CyQ1k0C%26pg%3DPA343&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-20"><a href="#cite_ref-20">^</a> Bennet, pp. 60-63 </li> <li id="cite_note-21"><a href="#cite_ref-21">^</a> Bennett, p. 53 </li> <li id="cite_note-bennett55-22">^ <a href="#cite_ref-bennett55_22-0">a</a> <a href="#cite_ref-bennett55_22-1">b</a> Bennet, p. 55 </li> <li id="cite_note-23"><a href="#cite_ref-23">^</a> Bennet, pp. 57-58 </li> <li id="cite_note-Neighbors-24">^ <a href="#cite_ref-Neighbors_24-0">a</a> <a href="#cite_ref-Neighbors_24-1">b</a> <a href="#cite_ref-Neighbors_24-2">c</a> <a href="#cite_ref-Neighbors_24-3">d</a> <a href="#cite_ref-Neighbors_24-4">e</a> <a href="#cite_ref-Neighbors_24-5">f</a> <a href="#cite_ref-Neighbors_24-6">g</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPat_Brennan2020" class="citation web cs1">Pat Brennan (10 November 2020). <a rel="nofollow" class="external text" href="https://exoplanets.nasa.gov/news/1665/life-in-our-solar-system-meet-the-neighbors/">"Life in Our Solar System? Meet the Neighbors"</a>. NASA. Retrieved 30 March 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Life+in+Our+Solar+System%3F+Meet+the+Neighbors&rft.pub=NASA&rft.date=2020-11-10&rft.au=Pat+Brennan&rft_id=https%3A%2F%2Fexoplanets.nasa.gov%2Fnews%2F1665%2Flife-in-our-solar-system-meet-the-neighbors%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFVicky_Stein2023" class="citation web cs1">Vicky Stein (16 February 2023). <a rel="nofollow" class="external text" href="https://www.space.com/goldilocks-zone-habitable-area-life">"Goldilocks zone: Everything you need to know about the habitable sweet spot"</a>. Space.com. Retrieved 22 April 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Goldilocks+zone%3A+Everything+you+need+to+know+about+the+habitable+sweet+spot&rft.pub=Space.com&rft.date=2023-02-16&rft.au=Vicky+Stein&rft_id=https%3A%2F%2Fwww.space.com%2Fgoldilocks-zone-habitable-area-life&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-26"><a href="#cite_ref-26">^</a> Bennet, p. 65 </li> <li id="cite_note-27"><a href="#cite_ref-27">^</a> Aguilera Mochon, pp. 9–10 </li> <li id="cite_note-28"><a href="#cite_ref-28">^</a> Bennet, p. 51 </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="CITEREFSteigerWhite1986" class="citation book cs1">Steiger, Brad; White, John, eds. (1986). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=vgQj5D524PYC&pg=PA3">Other Worlds, Other Universes</a>. Health Research Books. p. 3. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7873-1291-6" title="Special:BookSources/978-0-7873-1291-6"><bdi>978-0-7873-1291-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Other+Worlds%2C+Other+Universes&rft.pages=3&rft.pub=Health+Research+Books&rft.date=1986&rft.isbn=978-0-7873-1291-6&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DvgQj5D524PYC%26pg%3DPA3&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFFilkinHawking1998" class="citation book cs1">Filkin, David; Hawking, Stephen W. (1998). <a rel="nofollow" class="external text" href="https://archive.org/details/stephenhawkingsu00filk">Stephen Hawking's universe: the cosmos explained</a>. Art of Mentoring Series. Basic Books. p. <a rel="nofollow" class="external text" href="https://archive.org/details/stephenhawkingsu00filk/page/194">194</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-465-08198-1" title="Special:BookSources/978-0-465-08198-1"><bdi>978-0-465-08198-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Stephen+Hawking%27s+universe%3A+the+cosmos+explained&rft.series=Art+of+Mentoring+Series&rft.pages=194&rft.pub=Basic+Books&rft.date=1998&rft.isbn=978-0-465-08198-1&rft.aulast=Filkin&rft.aufirst=David&rft.au=Hawking%2C+Stephen+W.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fstephenhawkingsu00filk&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-31"><a href="#cite_ref-31">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRauchfuss2008" class="citation book cs1">Rauchfuss, Horst (2008). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=aRkvNoDYtvEC&pg=PA300">Chemical Evolution and the Origin of Life</a>. trans. Terence N. Mitchell. Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-3-540-78822-5" title="Special:BookSources/978-3-540-78822-5"><bdi>978-3-540-78822-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Chemical+Evolution+and+the+Origin+of+Life&rft.pub=Springer&rft.date=2008&rft.isbn=978-3-540-78822-5&rft.aulast=Rauchfuss&rft.aufirst=Horst&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DaRkvNoDYtvEC%26pg%3DPA300&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-32"><a href="#cite_ref-32">^</a> Aguilera Mochón, p. 66 </li> <li id="cite_note-33"><a href="#cite_ref-33">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMorgan_Kelly2012" class="citation web cs1">Morgan Kelly (26 April 2012). <a rel="nofollow" class="external text" href="https://www.princeton.edu/news/2012/04/26/expectation-extraterrestrial-life-built-more-optimism-evidence-study-finds">"Expectation of extraterrestrial life built more on optimism than evidence, study finds"</a>. Princeton University. Retrieved 22 April 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Expectation+of+extraterrestrial+life+built+more+on+optimism+than+evidence%2C+study+finds&rft.pub=Princeton+University&rft.date=2012-04-26&rft.au=Morgan+Kelly&rft_id=https%3A%2F%2Fwww.princeton.edu%2Fnews%2F2012%2F04%2F26%2Fexpectation-extraterrestrial-life-built-more-optimism-evidence-study-finds&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-December_2002-34"><a href="#cite_ref-December_2002_34-0">^</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.setileague.org/askdr/drake.htm">"Chapter 3 – Philosophy: "Solving the Drake Equation"</a>. SETI League. December 2002. Retrieved 24 July 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Chapter+3+%E2%80%93+Philosophy%3A+%22Solving+the+Drake+Equation&rft.pub=SETI+League&rft.date=2002-12&rft_id=http%3A%2F%2Fwww.setileague.org%2Faskdr%2Fdrake.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NOVA-35"><a href="#cite_ref-NOVA_35-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAguirre2008" class="citation web cs1">Aguirre, L. (1 July 2008). <a rel="nofollow" class="external text" href="https://www.pbs.org/wgbh/nova/origins/drake.html">"The Drake Equation"</a>. <a href="/wiki/Nova_ScienceNow" title="Nova ScienceNow">Nova ScienceNow</a>. <a href="/wiki/PBS" title="PBS">PBS</a>. Retrieved 7 March 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Nova+ScienceNow&rft.atitle=The+Drake+Equation&rft.date=2008-07-01&rft.aulast=Aguirre&rft.aufirst=L.&rft_id=https%3A%2F%2Fwww.pbs.org%2Fwgbh%2Fnova%2Forigins%2Fdrake.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Burchell-36"><a href="#cite_ref-Burchell_36-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBurchell2006" class="citation journal cs1">Burchell, M. J. (2006). "W(h)ither the Drake equation?". International Journal of Astrobiology. 5 (3): 243–250. <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/2006IJAsB...5..243B">2006IJAsB...5..243B</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%2FS1473550406003107">10.1017/S1473550406003107</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:121060763">121060763</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=International+Journal+of+Astrobiology&rft.atitle=W%28h%29ither+the+Drake+equation%3F&rft.volume=5&rft.issue=3&rft.pages=243-250&rft.date=2006&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A121060763%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1017%2FS1473550406003107&rft_id=info%3Abibcode%2F2006IJAsB...5..243B&rft.aulast=Burchell&rft.aufirst=M.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-37"><a href="#cite_ref-37">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCohenStewart2002" class="citation book cs1"><a href="/wiki/Jack_Cohen_(biologist)" title="Jack Cohen (biologist)">Cohen, Jack</a>; <a href="/wiki/Ian_Stewart_(mathematician)" title="Ian Stewart (mathematician)">Stewart, Ian</a> (2002). "Chapter 6: What does a Martian look like?". <a href="/wiki/Evolving_the_Alien:_The_Science_of_Extraterrestrial_Life" class="mw-redirect" title="Evolving the Alien: The Science of Extraterrestrial Life">Evolving the Alien: The Science of Extraterrestrial Life</a>. Hoboken, NJ: John Wiley and Sons. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-09-187927-3" title="Special:BookSources/978-0-09-187927-3"><bdi>978-0-09-187927-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Chapter+6%3A+What+does+a+Martian+look+like%3F&rft.btitle=Evolving+the+Alien%3A+The+Science+of+Extraterrestrial+Life&rft.place=Hoboken%2C+NJ&rft.pub=John+Wiley+and+Sons&rft.date=2002&rft.isbn=978-0-09-187927-3&rft.aulast=Cohen&rft.aufirst=Jack&rft.au=Stewart%2C+Ian&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFMacrobert2016" class="citation news cs1">Macrobert, Alan (13 October 2016). <a rel="nofollow" class="external text" href="https://skyandtelescope.org/astronomy-news/universe-2-trillion-galaxies/">"About those 2 trillion new galaxies..."</a> Sky & Telescope. Retrieved 24 May 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Sky+%26+Telescope&rft.atitle=About+those+2+trillion+new+galaxies...&rft.date=2016-10-13&rft.aulast=Macrobert&rft.aufirst=Alan&rft_id=https%3A%2F%2Fskyandtelescope.org%2Fastronomy-news%2Funiverse-2-trillion-galaxies%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-marcyprogth05-39"><a href="#cite_ref-marcyprogth05_39-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMarcyButlerFischer2005" class="citation journal cs1">Marcy, G.; Butler, R.; Fischer, D.; et al. (2005). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20081002085400/http://ptp.ipap.jp/link?PTPS%2F158%2F24">"Observed Properties of Exoplanets: Masses, Orbits and Metallicities"</a>. Progress of Theoretical Physics Supplement. 158: 24–42. <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/0505003">astro-ph/0505003</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/2005PThPS.158...24M">2005PThPS.158...24M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1143%2FPTPS.158.24">10.1143/PTPS.158.24</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:16349463">16349463</a>. Archived from <a rel="nofollow" class="external text" href="http://ptp.ipap.jp/link?PTPS/158/24">the original</a> on 2 October 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Progress+of+Theoretical+Physics+Supplement&rft.atitle=Observed+Properties+of+Exoplanets%3A+Masses%2C+Orbits+and+Metallicities&rft.volume=158&rft.pages=24-42&rft.date=2005&rft_id=info%3Aarxiv%2Fastro-ph%2F0505003&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A16349463%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1143%2FPTPS.158.24&rft_id=info%3Abibcode%2F2005PThPS.158...24M&rft.aulast=Marcy&rft.aufirst=G.&rft.au=Butler%2C+R.&rft.au=Fischer%2C+D.&rft_id=http%3A%2F%2Fptp.ipap.jp%2Flink%3FPTPS%2F158%2F24&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Swift2013-40"><a href="#cite_ref-Swift2013_40-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSwiftJohnsonMortonCrepp2013" class="citation journal cs1">Swift, Jonathan J.; Johnson, John Asher; Morton, Timothy D.; Crepp, Justin R.; Montet, Benjamin T.; et al. (January 2013). "Characterizing the Cool KOIs. IV. Kepler-32 as a Prototype for the Formation of Compact Planetary Systems throughout the Galaxy". The Astrophysical Journal. 764 (1). 105. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1301.0023">1301.0023</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/2013ApJ...764..105S">2013ApJ...764..105S</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%2F0004-637X%2F764%2F1%2F105">10.1088/0004-637X/764/1/105</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:43750666">43750666</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=Characterizing+the+Cool+KOIs.+IV.+Kepler-32+as+a+Prototype+for+the+Formation+of+Compact+Planetary+Systems+throughout+the+Galaxy&rft.volume=764&rft.issue=1&rft.pages=105&rft.date=2013-01&rft_id=info%3Aarxiv%2F1301.0023&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A43750666%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1088%2F0004-637X%2F764%2F1%2F105&rft_id=info%3Abibcode%2F2013ApJ...764..105S&rft.aulast=Swift&rft.aufirst=Jonathan+J.&rft.au=Johnson%2C+John+Asher&rft.au=Morton%2C+Timothy+D.&rft.au=Crepp%2C+Justin+R.&rft.au=Montet%2C+Benjamin+T.&rft.au=Fabrycky%2C+Daniel+C.&rft.au=Muirhead%2C+Philip+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-space20130102-41"><a href="#cite_ref-space20130102_41-0">^</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://web.archive.org/web/20130103060601/http://www.space.com/19103-milky-way-100-billion-planets.html">"100 Billion Alien Planets Fill Our Milky Way Galaxy: Study"</a>. Space.com. 2 January 2013. Archived from <a rel="nofollow" class="external text" href="http://www.space.com/19103-milky-way-100-billion-planets.html">the original</a> on 3 January 2013. Retrieved 10 March 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space.com&rft.atitle=100+Billion+Alien+Planets+Fill+Our+Milky+Way+Galaxy%3A+Study&rft.date=2013-01-02&rft_id=http%3A%2F%2Fwww.space.com%2F19103-milky-way-100-billion-planets.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NYT-20150803-42"><a href="#cite_ref-NYT-20150803_42-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOverbye2015" class="citation news cs1"><a href="/wiki/Dennis_Overbye" title="Dennis Overbye">Overbye, Dennis</a> (3 August 2015). <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2015/08/04/science/space/the-flip-side-of-optimism-about-life-on-other-planets.html">"The Flip Side of Optimism About Life on Other Planets"</a>. <a href="/wiki/The_New_York_Times" title="The New York Times">The New York Times</a>. Archived from <a rel="nofollow" class="external text" href="https://www.nytimes.com/2015/08/04/science/space/the-flip-side-of-optimism-about-life-on-other-planets.html">the original</a> on 1 January 2022. Retrieved 29 October 2015.</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+Flip+Side+of+Optimism+About+Life+on+Other+Planets&rft.date=2015-08-03&rft.aulast=Overbye&rft.aufirst=Dennis&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2015%2F08%2F04%2Fscience%2Fspace%2Fthe-flip-side-of-optimism-about-life-on-other-planets.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-43"><a href="#cite_ref-43">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWangBraunstein2023" class="citation journal cs1">Wang, Zhi-Wei; Braunstein, Samuel L. (2023). "Sciama's argument on life in a random universe and distinguishing apples from oranges". Nature Astronomy. 7 (2023): 755–756. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/2109.10241">2109.10241</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/2023NatAs...7..755W">2023NatAs...7..755W</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%2Fs41550-023-02014-9">10.1038/s41550-023-02014-9</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature+Astronomy&rft.atitle=Sciama%27s+argument+on+life+in+a+random+universe+and+distinguishing+apples+from+oranges&rft.volume=7&rft.issue=2023&rft.pages=755-756&rft.date=2023&rft_id=info%3Aarxiv%2F2109.10241&rft_id=info%3Adoi%2F10.1038%2Fs41550-023-02014-9&rft_id=info%3Abibcode%2F2023NatAs...7..755W&rft.aulast=Wang&rft.aufirst=Zhi-Wei&rft.au=Braunstein%2C+Samuel+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-44"><a href="#cite_ref-44">^</a> Bennett, p. 3 </li> <li id="cite_note-45"><a href="#cite_ref-45">^</a> Aguilera Mochón, p. 42 </li> <li id="cite_note-46"><a href="#cite_ref-46">^</a> Aguilera Mochón, p. 58 </li> <li id="cite_note-47"><a href="#cite_ref-47">^</a> Aguilera Mochón, p. 51 </li> <li id="cite_note-48"><a href="#cite_ref-48">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBondO'BrienLauretta2010" class="citation journal cs1">Bond, Jade C.; O'Brien, David P.; Lauretta, Dante S. (June 2010). "The Compositional Diversity of Extrasolar Terrestrial Planets. I. In Situ Simulations". The Astrophysical Journal. 715 (2): 1050–1070. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1004.0971">1004.0971</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/2010ApJ...715.1050B">2010ApJ...715.1050B</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%2F0004-637X%2F715%2F2%2F1050">10.1088/0004-637X/715/2/1050</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:118481496">118481496</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=The+Compositional+Diversity+of+Extrasolar+Terrestrial+Planets.+I.+In+Situ+Simulations&rft.volume=715&rft.issue=2&rft.pages=1050-1070&rft.date=2010-06&rft_id=info%3Aarxiv%2F1004.0971&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A118481496%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1088%2F0004-637X%2F715%2F2%2F1050&rft_id=info%3Abibcode%2F2010ApJ...715.1050B&rft.aulast=Bond&rft.aufirst=Jade+C.&rft.au=O%27Brien%2C+David+P.&rft.au=Lauretta%2C+Dante+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-49"><a href="#cite_ref-49">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPace2001" class="citation journal cs1">Pace, Norman R. (20 January 2001). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC33372">"The universal nature of biochemistry"</a>. Proceedings of the National Academy of Sciences of the United States of America. 98 (3): 805–808. <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/2001PNAS...98..805P">2001PNAS...98..805P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1073%2Fpnas.98.3.805">10.1073/pnas.98.3.805</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC33372">33372</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/11158550">11158550</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+National+Academy+of+Sciences+of+the+United+States+of+America&rft.atitle=The+universal+nature+of+biochemistry&rft.volume=98&rft.issue=3&rft.pages=805-808&rft.date=2001-01-20&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC33372%23id-name%3DPMC&rft_id=info%3Apmid%2F11158550&rft_id=info%3Adoi%2F10.1073%2Fpnas.98.3.805&rft_id=info%3Abibcode%2F2001PNAS...98..805P&rft.aulast=Pace&rft.aufirst=Norman+R.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC33372&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-50"><a href="#cite_ref-50">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNational_Research_Council2007" class="citation book cs1">National Research Council (2007). <a rel="nofollow" class="external text" href="http://www.nap.edu/read/11919/chapter/8#74">"6.2.2: Nonpolar Solvents"</a>. The Limits of Organic Life in Planetary Systems. The National Academies Press. p. 74. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17226%2F11919">10.17226/11919</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-309-10484-5" title="Special:BookSources/978-0-309-10484-5"><bdi>978-0-309-10484-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=6.2.2%3A+Nonpolar+Solvents&rft.btitle=The+Limits+of+Organic+Life+in+Planetary+Systems&rft.pages=74&rft.pub=The+National+Academies+Press&rft.date=2007&rft_id=info%3Adoi%2F10.17226%2F11919&rft.isbn=978-0-309-10484-5&rft.au=National+Research+Council&rft_id=http%3A%2F%2Fwww.nap.edu%2Fread%2F11919%2Fchapter%2F8%2374&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-51"><a href="#cite_ref-51">^</a> Aguilera Mochón, pp. 43–49 </li> <li id="cite_note-52"><a href="#cite_ref-52">^</a> Horowitz, N.H. (1986). Utopia and Back and the search for life in the solar system. New York: W.H. Freeman and Company. ISBN 0-7167-1766-2 </li> <li id="cite_note-53"><a href="#cite_ref-53">^</a> Bernstein, Harris; Byerly, Henry C.; Hopf, Frederick A.; et al. (June 1983). "The Darwinian Dynamic". The Quarterly Review of Biology. 58 (2): 185–207. doi:10.1086/413216. JSTOR 2828805. S2CID 83956410 </li> <li id="cite_note-54"><a href="#cite_ref-54">^</a> Aguilera Mochón, pp. 58–59 </li> <li id="cite_note-55"><a href="#cite_ref-55">^</a> Aguilera Mochón, pp. 42–43 </li> <li id="cite_note-AM6166-56">^ <a href="#cite_ref-AM6166_56-0">a</a> <a href="#cite_ref-AM6166_56-1">b</a> Aguilera Mochón, pp. 61–66 </li> <li id="cite_note-57"><a href="#cite_ref-57">^</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.ox.ac.uk/news/2017-10-31-aliens-may-be-more-us-we-think">"Aliens may be more like us than we think"</a>. <a href="/wiki/University_of_Oxford" title="University of Oxford">University of Oxford</a>. 31 October 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Aliens+may+be+more+like+us+than+we+think&rft.pub=University+of+Oxford&rft.date=2017-10-31&rft_id=http%3A%2F%2Fwww.ox.ac.uk%2Fnews%2F2017-10-31-aliens-may-be-more-us-we-think&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-58"><a href="#cite_ref-58">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStevensonLarge2017" class="citation journal cs1">Stevenson, David S.; Large, Sean (25 October 2017). "Evolutionary exobiology: Towards the qualitative assessment of biological potential on exoplanets". International Journal of Astrobiology. 18 (3): 204–208. <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%2FS1473550417000349">10.1017/S1473550417000349</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:125275411">125275411</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=International+Journal+of+Astrobiology&rft.atitle=Evolutionary+exobiology%3A+Towards+the+qualitative+assessment+of+biological+potential+on+exoplanets&rft.volume=18&rft.issue=3&rft.pages=204-208&rft.date=2017-10-25&rft_id=info%3Adoi%2F10.1017%2FS1473550417000349&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A125275411%23id-name%3DS2CID&rft.aulast=Stevenson&rft.aufirst=David+S.&rft.au=Large%2C+Sean&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-59"><a href="#cite_ref-59">^</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.britannica.com/science/atmosphere/The-atmospheres-of-other-planets">"Atmosphere - Planets, Composition, Pressure | Britannica"</a>. www.britannica.com. Retrieved 17 April 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.britannica.com&rft.atitle=Atmosphere+-+Planets%2C+Composition%2C+Pressure+%7C+Britannica&rft_id=https%3A%2F%2Fwww.britannica.com%2Fscience%2Fatmosphere%2FThe-atmospheres-of-other-planets&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-60"><a href="#cite_ref-60">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAmilsGonzález-TorilFernández-RemolarGómez2007" class="citation journal cs1">Amils, Ricardo; González-Toril, Elena; Fernández-Remolar, David; Gómez, Felipe; Aguilera, Ángeles; Rodríguez, Nuria; Malki, Mustafá; García-Moyano, Antonio; Fairén, Alberto G.; de la Fuente, Vicenta; Luis Sanz, José (February 2007). <a rel="nofollow" class="external text" href="https://linkinghub.elsevier.com/retrieve/pii/S0032063306001826">"Extreme environments as Mars terrestrial analogs: The Rio Tinto case"</a>. Planetary and Space Science. 55 (3): 370–381. <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/2007P&SS...55..370A">2007P&SS...55..370A</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%2Fj.pss.2006.02.006">10.1016/j.pss.2006.02.006</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Planetary+and+Space+Science&rft.atitle=Extreme+environments+as+Mars+terrestrial+analogs%3A+The+Rio+Tinto+case&rft.volume=55&rft.issue=3&rft.pages=370-381&rft.date=2007-02&rft_id=info%3Adoi%2F10.1016%2Fj.pss.2006.02.006&rft_id=info%3Abibcode%2F2007P%26SS...55..370A&rft.aulast=Amils&rft.aufirst=Ricardo&rft.au=Gonz%C3%A1lez-Toril%2C+Elena&rft.au=Fern%C3%A1ndez-Remolar%2C+David&rft.au=G%C3%B3mez%2C+Felipe&rft.au=Aguilera%2C+%C3%81ngeles&rft.au=Rodr%C3%ADguez%2C+Nuria&rft.au=Malki%2C+Mustaf%C3%A1&rft.au=Garc%C3%ADa-Moyano%2C+Antonio&rft.au=Fair%C3%A9n%2C+Alberto+G.&rft.au=de+la+Fuente%2C+Vicenta&rft.au=Luis+Sanz%2C+Jos%C3%A9&rft_id=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0032063306001826&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-61"><a href="#cite_ref-61">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDanielOgerWinter2006" class="citation journal cs1">Daniel, Isabelle; Oger, Philippe; Winter, Roland (2006). <a rel="nofollow" class="external text" href="https://xlink.rsc.org/?DOI=b517766a">"Origins of life and biochemistry under high-pressure conditions"</a>. Chemical Society Reviews. 35 (10): 858–875. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1039%2Fb517766a">10.1039/b517766a</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/0306-0012">0306-0012</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/17003893">17003893</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Chemical+Society+Reviews&rft.atitle=Origins+of+life+and+biochemistry+under+high-pressure+conditions&rft.volume=35&rft.issue=10&rft.pages=858-875&rft.date=2006&rft.issn=0306-0012&rft_id=info%3Apmid%2F17003893&rft_id=info%3Adoi%2F10.1039%2Fb517766a&rft.aulast=Daniel&rft.aufirst=Isabelle&rft.au=Oger%2C+Philippe&rft.au=Winter%2C+Roland&rft_id=https%3A%2F%2Fxlink.rsc.org%2F%3FDOI%3Db517766a&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-62"><a href="#cite_ref-62">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDongYu2007" class="citation journal cs1">Dong, Hailiang; Yu, Bingsong (1 September 2007). <a rel="nofollow" class="external text" href="https://doi.org/10.18814%2Fepiiugs%2F2007%2Fv30i3%2F003">"Geomicrobiological processes in extreme environments: A review"</a>. Episodes. 30 (3): 202–216. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.18814%2Fepiiugs%2F2007%2Fv30i3%2F003">10.18814/epiiugs/2007/v30i3/003</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/0705-3797">0705-3797</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Episodes&rft.atitle=Geomicrobiological+processes+in+extreme+environments%3A+A+review&rft.volume=30&rft.issue=3&rft.pages=202-216&rft.date=2007-09-01&rft_id=info%3Adoi%2F10.18814%2Fepiiugs%2F2007%2Fv30i3%2F003&rft.issn=0705-3797&rft.aulast=Dong&rft.aufirst=Hailiang&rft.au=Yu%2C+Bingsong&rft_id=https%3A%2F%2Fdoi.org%2F10.18814%252Fepiiugs%252F2007%252Fv30i3%252F003&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-:1-63">^ <a href="#cite_ref-:1_63-0">a</a> <a href="#cite_ref-:1_63-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGeorgievaLittleMaslennikovGlover2021" class="citation journal cs1">Georgieva, Magdalena N.; Little, Crispin T.S.; Maslennikov, Valeriy V.; Glover, Adrian G.; Ayupova, Nuriya R.; Herrington, Richard J. (June 2021). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.earscirev.2021.103602">"The history of life at hydrothermal vents"</a>. Earth-Science Reviews. 217: 103602. <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/2021ESRv..21703602G">2021ESRv..21703602G</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%2Fj.earscirev.2021.103602">10.1016/j.earscirev.2021.103602</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Earth-Science+Reviews&rft.atitle=The+history+of+life+at+hydrothermal+vents&rft.volume=217&rft.pages=103602&rft.date=2021-06&rft_id=info%3Adoi%2F10.1016%2Fj.earscirev.2021.103602&rft_id=info%3Abibcode%2F2021ESRv..21703602G&rft.aulast=Georgieva&rft.aufirst=Magdalena+N.&rft.au=Little%2C+Crispin+T.S.&rft.au=Maslennikov%2C+Valeriy+V.&rft.au=Glover%2C+Adrian+G.&rft.au=Ayupova%2C+Nuriya+R.&rft.au=Herrington%2C+Richard+J.&rft_id=https%3A%2F%2Fdoi.org%2F10.1016%252Fj.earscirev.2021.103602&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-64"><a href="#cite_ref-64">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZahnleLupuCatlingWogan2020" class="citation journal cs1">Zahnle, Kevin J.; Lupu, Roxana; Catling, David C.; Wogan, Nick (1 June 2020). <a rel="nofollow" class="external text" href="https://doi.org/10.3847%2FPSJ%2Fab7e2c">"Creation and Evolution of Impact-generated Reduced Atmospheres of Early Earth"</a>. The Planetary Science Journal. 1 (1): 11. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/2001.00095">2001.00095</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/2020PSJ.....1...11Z">2020PSJ.....1...11Z</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%2FPSJ%2Fab7e2c">10.3847/PSJ/ab7e2c</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/2632-3338">2632-3338</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Planetary+Science+Journal&rft.atitle=Creation+and+Evolution+of+Impact-generated+Reduced+Atmospheres+of+Early+Earth&rft.volume=1&rft.issue=1&rft.pages=11&rft.date=2020-06-01&rft_id=info%3Aarxiv%2F2001.00095&rft.issn=2632-3338&rft_id=info%3Adoi%2F10.3847%2FPSJ%2Fab7e2c&rft_id=info%3Abibcode%2F2020PSJ.....1...11Z&rft.aulast=Zahnle&rft.aufirst=Kevin+J.&rft.au=Lupu%2C+Roxana&rft.au=Catling%2C+David+C.&rft.au=Wogan%2C+Nick&rft_id=https%3A%2F%2Fdoi.org%2F10.3847%252FPSJ%252Fab7e2c&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-65"><a href="#cite_ref-65">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAtreyaMahaffyNiemannWong2003" class="citation journal cs1">Atreya, S.K; Mahaffy, P.R; Niemann, H.B; Wong, M.H; Owen, T.C (February 2003). <a rel="nofollow" class="external text" href="https://linkinghub.elsevier.com/retrieve/pii/S0032063302001447">"Composition and origin of the atmosphere of Jupiter—an update, and implications for the extrasolar giant planets"</a>. Planetary and Space Science. 51 (2): 105–112. <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/2003P&SS...51..105A">2003P&SS...51..105A</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%2FS0032-0633%2802%2900144-7">10.1016/S0032-0633(02)00144-7</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Planetary+and+Space+Science&rft.atitle=Composition+and+origin+of+the+atmosphere+of+Jupiter%E2%80%94an+update%2C+and+implications+for+the+extrasolar+giant+planets&rft.volume=51&rft.issue=2&rft.pages=105-112&rft.date=2003-02&rft_id=info%3Adoi%2F10.1016%2FS0032-0633%2802%2900144-7&rft_id=info%3Abibcode%2F2003P%26SS...51..105A&rft.aulast=Atreya&rft.aufirst=S.K&rft.au=Mahaffy%2C+P.R&rft.au=Niemann%2C+H.B&rft.au=Wong%2C+M.H&rft.au=Owen%2C+T.C&rft_id=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0032063302001447&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-66"><a href="#cite_ref-66">^</a> Bennett, pp. 3-4 </li> <li id="cite_note-67"><a href="#cite_ref-67">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMarcqMillsParkinsonVandaele2017" class="citation journal cs1">Marcq, Emmanuel; Mills, Franklin P.; Parkinson, Christopher D.; Vandaele, Ann Carine (30 November 2017). <a rel="nofollow" class="external text" href="https://hal-insu.archives-ouvertes.fr/insu-01656562/file/EMFMCP.pdf">"Composition and Chemistry of the Neutral Atmosphere of Venus"</a> (PDF). Space Science Reviews. 214 (1): 10. <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%2Fs11214-017-0438-5">10.1007/s11214-017-0438-5</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/1572-9672">1572-9672</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:255067610">255067610</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space+Science+Reviews&rft.atitle=Composition+and+Chemistry+of+the+Neutral+Atmosphere+of+Venus&rft.volume=214&rft.issue=1&rft.pages=10&rft.date=2017-11-30&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A255067610%23id-name%3DS2CID&rft.issn=1572-9672&rft_id=info%3Adoi%2F10.1007%2Fs11214-017-0438-5&rft.aulast=Marcq&rft.aufirst=Emmanuel&rft.au=Mills%2C+Franklin+P.&rft.au=Parkinson%2C+Christopher+D.&rft.au=Vandaele%2C+Ann+Carine&rft_id=https%3A%2F%2Fhal-insu.archives-ouvertes.fr%2Finsu-01656562%2Ffile%2FEMFMCP.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://depts.washington.edu/astrobio/wordpress/about-us/what-is-astrobiology/">"What Is Astrobiology?"</a>. University of Washington. Retrieved 28 April 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=What+Is+Astrobiology%3F&rft.pub=University+of+Washington&rft_id=https%3A%2F%2Fdepts.washington.edu%2Fastrobio%2Fwordpress%2Fabout-us%2Fwhat-is-astrobiology%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NYT-20210208-69"><a href="#cite_ref-NYT-20210208_69-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChangStirone2021" class="citation news cs1">Chang, Kenneth; Stirone, Shannon (8 February 2021). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2021/02/08/science/venus-life-phosphine.html">"Life on Venus? The Picture Gets Cloudier – Despite doubts from many scientists, a team of researchers who said they had detected an unusual gas in the planet's atmosphere were still confident of their findings"</a>. <a href="/wiki/The_New_York_Times" title="The New York Times">The New York Times</a>. Retrieved 8 February 2021.</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=Life+on+Venus%3F+The+Picture+Gets+Cloudier+%E2%80%93+Despite+doubts+from+many+scientists%2C+a+team+of+researchers+who+said+they+had+detected+an+unusual+gas+in+the+planet%27s+atmosphere+were+still+confident+of+their+findings.&rft.date=2021-02-08&rft.aulast=Chang&rft.aufirst=Kenneth&rft.au=Stirone%2C+Shannon&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2021%2F02%2F08%2Fscience%2Fvenus-life-phosphine.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NASA-20180625-70"><a href="#cite_ref-NASA-20180625_70-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCofieldChou2018" class="citation web cs1">Cofield, Calla; Chou, Felicia (25 June 2018). <a rel="nofollow" class="external text" href="https://www.jpl.nasa.gov/news/news.php?feature=7171">"NASA Asks: Will We Know Life When We See It?"</a>. <a href="/wiki/NASA" title="NASA">NASA</a>. Retrieved 26 June 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NASA+Asks%3A+Will+We+Know+Life+When+We+See+It%3F&rft.pub=NASA&rft.date=2018-06-25&rft.aulast=Cofield&rft.aufirst=Calla&rft.au=Chou%2C+Felicia&rft_id=https%3A%2F%2Fwww.jpl.nasa.gov%2Fnews%2Fnews.php%3Ffeature%3D7171&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-EA-20180625-71"><a href="#cite_ref-EA-20180625_71-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNightingale2018" class="citation news cs1">Nightingale, Sarah (25 June 2018). <a rel="nofollow" class="external text" href="https://ucrtoday.ucr.edu/54211">"UCR Team Among Scientists Developing Guidebook for Finding Life Beyond Earth"</a>. UCR Today. <a href="/wiki/University_of_California,_Riverside" title="University of California, Riverside">University of California, Riverside</a>. Retrieved 26 June 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=UCR+Today&rft.atitle=UCR+Team+Among+Scientists+Developing+Guidebook+for+Finding+Life+Beyond+Earth&rft.date=2018-06-25&rft.aulast=Nightingale&rft.aufirst=Sarah&rft_id=https%3A%2F%2Fucrtoday.ucr.edu%2F54211&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-disbelief-72">^ <a href="#cite_ref-disbelief_72-0">a</a> <a href="#cite_ref-disbelief_72-1">b</a> <a href="#cite_ref-disbelief_72-2">c</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrenson2006" class="citation web cs1">Crenson, Matt (6 August 2006). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110416094930/http://dsc.discovery.com/news/2006/08/08/marslife_spa.html?category=space&guid=20060808100030">"Experts: Little Evidence of Life on Mars"</a>. <a href="/wiki/Associated_Press" title="Associated Press">Associated Press</a>. Archived from <a rel="nofollow" class="external text" href="http://dsc.discovery.com/news/2006/08/08/marslife_spa.html?category=space&guid=20060808100030">the original</a> on 16 April 2011. Retrieved 8 March 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Experts%3A+Little+Evidence+of+Life+on+Mars&rft.pub=Associated+Press&rft.date=2006-08-06&rft.aulast=Crenson&rft.aufirst=Matt&rft_id=http%3A%2F%2Fdsc.discovery.com%2Fnews%2F2006%2F08%2F08%2Fmarslife_spa.html%3Fcategory%3Dspace%26guid%3D20060808100030&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-life-73">^ <a href="#cite_ref-life_73-0">a</a> <a href="#cite_ref-life_73-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcKayGibsonThomas-KeprtaVali1996" class="citation journal cs1">McKay, David S.; Gibson, Everett K. Jr.; Thomas-Keprta, Kathie L.; Vali, Hojatollah; Romanek, Christopher S.; et al. (August 1996). "Search for Past Life on Mars: Possible Relic Biogenic Activity in Martian Meteorite ALH84001". Science. 273 (5277): 924–930. <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/1996Sci...273..924M">1996Sci...273..924M</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.273.5277.924">10.1126/science.273.5277.924</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/8688069">8688069</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:40690489">40690489</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=Search+for+Past+Life+on+Mars%3A+Possible+Relic+Biogenic+Activity+in+Martian+Meteorite+ALH84001&rft.volume=273&rft.issue=5277&rft.pages=924-930&rft.date=1996-08&rft_id=info%3Adoi%2F10.1126%2Fscience.273.5277.924&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A40690489%23id-name%3DS2CID&rft_id=info%3Apmid%2F8688069&rft_id=info%3Abibcode%2F1996Sci...273..924M&rft.aulast=McKay&rft.aufirst=David+S.&rft.au=Gibson%2C+Everett+K.+Jr.&rft.au=Thomas-Keprta%2C+Kathie+L.&rft.au=Vali%2C+Hojatollah&rft.au=Romanek%2C+Christopher+S.&rft.au=Clemett%2C+Simon+J.&rft.au=Chillier%2C+Xavier+D.+F.&rft.au=Maechling%2C+Claude+R.&rft.au=Zare%2C+Richard+N.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NASA-20140227-74"><a href="#cite_ref-NASA-20140227_74-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWebster2014" class="citation web cs1">Webster, Guy (27 February 2014). <a rel="nofollow" class="external text" href="https://www.jpl.nasa.gov/news/news.php?release=2014-065&1">"NASA Scientists Find Evidence of Water in Meteorite, Reviving Debate Over Life on Mars"</a>. <a href="/wiki/NASA" title="NASA">NASA</a>. Retrieved 27 February 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=NASA&rft.atitle=NASA+Scientists+Find+Evidence+of+Water+in+Meteorite%2C+Reviving+Debate+Over+Life+on+Mars&rft.date=2014-02-27&rft.aulast=Webster&rft.aufirst=Guy&rft_id=http%3A%2F%2Fwww.jpl.nasa.gov%2Fnews%2Fnews.php%3Frelease%3D2014-065%261&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-SP-20140228-75"><a href="#cite_ref-SP-20140228_75-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGannon2014" class="citation web cs1">Gannon, Megan (28 February 2014). <a rel="nofollow" class="external text" href="http://www.space.com/24834-strange-mars-meteorite-life-evidence-debate.html">"Mars Meteorite with Odd 'Tunnels' & 'Spheres' Revives Debate Over Ancient Martian Life"</a>. <a href="/wiki/Space.com" title="Space.com">Space.com</a>. Retrieved 28 February 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Space.com&rft.atitle=Mars+Meteorite+with+Odd+%27Tunnels%27+%26+%27Spheres%27+Revives+Debate+Over+Ancient+Martian+Life&rft.date=2014-02-28&rft.aulast=Gannon&rft.aufirst=Megan&rft_id=http%3A%2F%2Fwww.space.com%2F24834-strange-mars-meteorite-life-evidence-debate.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Chambers-76">^ <a href="#cite_ref-Chambers_76-0">a</a> <a href="#cite_ref-Chambers_76-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChambers1999" class="citation book cs1">Chambers, Paul (1999). <a rel="nofollow" class="external text" href="https://archive.org/details/lifeonmarscomple00cham">Life on Mars; The Complete Story</a>. London: Blandford. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7137-2747-0" title="Special:BookSources/978-0-7137-2747-0"><bdi>978-0-7137-2747-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Life+on+Mars%3B+The+Complete+Story&rft.place=London&rft.pub=Blandford&rft.date=1999&rft.isbn=978-0-7137-2747-0&rft.aulast=Chambers&rft.aufirst=Paul&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Flifeonmarscomple00cham&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 id="CITEREFKleinLevinLevinOyama1976" class="citation journal cs1">Klein, Harold P.; Levin, Gilbert V.; Levin, Gilbert V.; Oyama, Vance I.; Lederberg, Joshua; Rich, Alexander; Hubbard, Jerry S.; Hobby, George L.; Straat, Patricia A.; Berdahl, Bonnie J.; Carle, Glenn C.; Brown, Frederick S.; Johnson, Richard D. (1 October 1976). "The Viking Biological Investigation: Preliminary Results". Science. 194 (4260): 99–105. <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/1976Sci...194...99K">1976Sci...194...99K</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.194.4260.99">10.1126/science.194.4260.99</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/17793090">17793090</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:24957458">24957458</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=The+Viking+Biological+Investigation%3A+Preliminary+Results&rft.volume=194&rft.issue=4260&rft.pages=99-105&rft.date=1976-10-01&rft_id=info%3Adoi%2F10.1126%2Fscience.194.4260.99&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A24957458%23id-name%3DS2CID&rft_id=info%3Apmid%2F17793090&rft_id=info%3Abibcode%2F1976Sci...194...99K&rft.aulast=Klein&rft.aufirst=Harold+P.&rft.au=Levin%2C+Gilbert+V.&rft.au=Levin%2C+Gilbert+V.&rft.au=Oyama%2C+Vance+I.&rft.au=Lederberg%2C+Joshua&rft.au=Rich%2C+Alexander&rft.au=Hubbard%2C+Jerry+S.&rft.au=Hobby%2C+George+L.&rft.au=Straat%2C+Patricia+A.&rft.au=Berdahl%2C+Bonnie+J.&rft.au=Carle%2C+Glenn+C.&rft.au=Brown%2C+Frederick+S.&rft.au=Johnson%2C+Richard+D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Beegle-78"><a href="#cite_ref-Beegle_78-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBeegleWilsonAbilleiraJordan2007" class="citation journal cs1">Beegle, Luther W.; Wilson, Michael G.; Abilleira, Fernando; Jordan, James F.; Wilson, Gregory R. (August 2007). "A Concept for NASA's Mars 2016 Astrobiology Field Laboratory". Astrobiology. 7 (4): 545–577. <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/2007AsBio...7..545B">2007AsBio...7..545B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1089%2Fast.2007.0153">10.1089/ast.2007.0153</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/17723090">17723090</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astrobiology&rft.atitle=A+Concept+for+NASA%27s+Mars+2016+Astrobiology+Field+Laboratory&rft.volume=7&rft.issue=4&rft.pages=545-577&rft.date=2007-08&rft_id=info%3Apmid%2F17723090&rft_id=info%3Adoi%2F10.1089%2Fast.2007.0153&rft_id=info%3Abibcode%2F2007AsBio...7..545B&rft.aulast=Beegle&rft.aufirst=Luther+W.&rft.au=Wilson%2C+Michael+G.&rft.au=Abilleira%2C+Fernando&rft.au=Jordan%2C+James+F.&rft.au=Wilson%2C+Gregory+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20121019105332/http://www.esa.int/SPECIALS/ExoMars/SEMK39JJX7F_0.html">"ExoMars rover"</a>. ESA. Archived from <a rel="nofollow" class="external text" href="http://www.esa.int/SPECIALS/ExoMars/SEMK39JJX7F_0.html">the original</a> on 19 October 2012. Retrieved 14 April 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=ExoMars+rover&rft.pub=ESA&rft_id=http%3A%2F%2Fwww.esa.int%2FSPECIALS%2FExoMars%2FSEMK39JJX7F_0.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFBerger2005" class="citation news cs1">Berger, Brian (16 February 2005). <a rel="nofollow" class="external text" href="http://www.space.com/scienceastronomy/mars_life_050216.html">"Exclusive: NASA Researchers Claim Evidence of Present Life on Mars"</a>. Space.com.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space.com&rft.atitle=Exclusive%3A+NASA+Researchers+Claim+Evidence+of+Present+Life+on+Mars&rft.date=2005-02-16&rft.aulast=Berger&rft.aufirst=Brian&rft_id=http%3A%2F%2Fwww.space.com%2Fscienceastronomy%2Fmars_life_050216.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation news cs1"><a rel="nofollow" class="external text" href="http://www.spacetoday.net/Summary/2804">"NASA denies Mars life reports"</a>. spacetoday.net. 19 February 2005.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=NASA+denies+Mars+life+reports&rft.date=2005-02-19&rft_id=http%3A%2F%2Fwww.spacetoday.net%2FSummary%2F2804&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Gale_Crater2-82"><a href="#cite_ref-Gale_Crater2_82-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChow2011" class="citation web cs1">Chow, Dennis (22 July 2011). <a rel="nofollow" class="external text" href="http://www.space.com/12394-nasa-mars-rover-landing-site-unveiled.html">"NASA's Next Mars Rover to Land at Huge Gale Crater"</a>. <a href="/wiki/Space.com" title="Space.com">Space.com</a>. Retrieved 22 July 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NASA%27s+Next+Mars+Rover+to+Land+at+Huge+Gale+Crater&rft.pub=Space.com&rft.date=2011-07-22&rft.aulast=Chow&rft.aufirst=Dennis&rft_id=http%3A%2F%2Fwww.space.com%2F12394-nasa-mars-rover-landing-site-unveiled.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Gale_Crater3-83"><a href="#cite_ref-Gale_Crater3_83-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAmos2011" class="citation news cs1">Amos, Jonathan (22 July 2011). <a rel="nofollow" class="external text" href="https://www.bbc.co.uk/news/science-environment-14249524">"Mars rover aims for deep crater"</a>. <a href="/wiki/BBC_News" title="BBC News">BBC News</a>. Retrieved 22 July 2011.</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=Mars+rover+aims+for+deep+crater&rft.date=2011-07-22&rft.aulast=Amos&rft.aufirst=Jonathan&rft_id=https%3A%2F%2Fwww.bbc.co.uk%2Fnews%2Fscience-environment-14249524&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-ColorCatalog-84"><a href="#cite_ref-ColorCatalog_84-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCofield2015" class="citation news cs1">Cofield, Calla (30 March 2015). <a rel="nofollow" class="external text" href="http://www.space.com/28906-alien-life-earth-microbe-catalog.html">"Catalog of Earth Microbes Could Help Find Alien Life"</a>. Space.com. Retrieved 11 May 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space.com&rft.atitle=Catalog+of+Earth+Microbes+Could+Help+Find+Alien+Life&rft.date=2015-03-30&rft.aulast=Cofield&rft.aufirst=Calla&rft_id=http%3A%2F%2Fwww.space.com%2F28906-alien-life-earth-microbe-catalog.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Callahan-85"><a href="#cite_ref-Callahan_85-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCallahanSmithCleavesRuzica2011" class="citation journal cs1">Callahan, M.P.; Smith, K.E.; Cleaves, H.J.; Ruzica, J.; Stern, J.C.; Glavin, D.P.; House, C.H.; Dworkin, J.P. (11 August 2011). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3161613">"Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases"</a>. Proceedings of the National Academy of Sciences. 108 (34): 13995–13998. <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/2011PNAS..10813995C">2011PNAS..10813995C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1073%2Fpnas.1106493108">10.1073/pnas.1106493108</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3161613">3161613</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/21836052">21836052</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+National+Academy+of+Sciences&rft.atitle=Carbonaceous+meteorites+contain+a+wide+range+of+extraterrestrial+nucleobases&rft.volume=108&rft.issue=34&rft.pages=13995-13998&rft.date=2011-08-11&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3161613%23id-name%3DPMC&rft_id=info%3Apmid%2F21836052&rft_id=info%3Adoi%2F10.1073%2Fpnas.1106493108&rft_id=info%3Abibcode%2F2011PNAS..10813995C&rft.aulast=Callahan&rft.aufirst=M.P.&rft.au=Smith%2C+K.E.&rft.au=Cleaves%2C+H.J.&rft.au=Ruzica%2C+J.&rft.au=Stern%2C+J.C.&rft.au=Glavin%2C+D.P.&rft.au=House%2C+C.H.&rft.au=Dworkin%2C+J.P.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3161613&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Steigerwald-86"><a href="#cite_ref-Steigerwald_86-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSteigerwald2011" class="citation web cs1">Steigerwald, John (8 August 2011). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200511192941/https://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html">"NASA Researchers: DNA Building Blocks Can Be Made in Space"</a>. <a href="/wiki/NASA" title="NASA">NASA</a>. Archived from <a rel="nofollow" class="external text" href="https://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html">the original</a> on 11 May 2020. Retrieved 10 August 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NASA+Researchers%3A+DNA+Building+Blocks+Can+Be+Made+in+Space&rft.pub=NASA&rft.date=2011-08-08&rft.aulast=Steigerwald&rft.aufirst=John&rft_id=http%3A%2F%2Fwww.nasa.gov%2Ftopics%2Fsolarsystem%2Ffeatures%2Fdna-meteorites.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Space-20111026-87">^ <a href="#cite_ref-Space-20111026_87-0">a</a> <a href="#cite_ref-Space-20111026_87-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChow2011" class="citation web cs1">Chow, Denise (26 October 2011). <a rel="nofollow" class="external text" href="http://www.space.com/13401-cosmic-star-dust-complex-organic-compounds.html">"Discovery: Cosmic Dust Contains Organic Matter from Stars"</a>. <a href="/wiki/Space.com" title="Space.com">Space.com</a>. Retrieved 26 October 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Discovery%3A+Cosmic+Dust+Contains+Organic+Matter+from+Stars&rft.pub=Space.com&rft.date=2011-10-26&rft.aulast=Chow&rft.aufirst=Denise&rft_id=http%3A%2F%2Fwww.space.com%2F13401-cosmic-star-dust-complex-organic-compounds.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-ScienceDaily-20111026-88"><a href="#cite_ref-ScienceDaily-20111026_88-0">^</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://www.sciencedaily.com/releases/2011/10/111026143721.htm">"Astronomers Discover Complex Organic Matter Exists Throughout the Universe"</a>. <a href="/wiki/ScienceDaily" title="ScienceDaily">ScienceDaily</a>. 26 October 2011. Retrieved 27 October 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=ScienceDaily&rft.atitle=Astronomers+Discover+Complex+Organic+Matter+Exists+Throughout+the+Universe&rft.date=2011-10-26&rft_id=https%3A%2F%2Fwww.sciencedaily.com%2Freleases%2F2011%2F10%2F111026143721.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Nature-20111026-89"><a href="#cite_ref-Nature-20111026_89-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKwokZhang2011" class="citation journal cs1">Kwok, Sun; Zhang, Yong (26 October 2011). "Mixed aromatic–aliphatic organic nanoparticles as carriers of unidentified infrared emission features". <a href="/wiki/Nature_(journal)" title="Nature (journal)">Nature</a>. 479 (7371): 80–3. <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/2011Natur.479...80K">2011Natur.479...80K</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%2Fnature10542">10.1038/nature10542</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/22031328">22031328</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:4419859">4419859</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=Mixed+aromatic%E2%80%93aliphatic+organic+nanoparticles+as+carriers+of+unidentified+infrared+emission+features&rft.volume=479&rft.issue=7371&rft.pages=80-3&rft.date=2011-10-26&rft_id=info%3Adoi%2F10.1038%2Fnature10542&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4419859%23id-name%3DS2CID&rft_id=info%3Apmid%2F22031328&rft_id=info%3Abibcode%2F2011Natur.479...80K&rft.aulast=Kwok&rft.aufirst=Sun&rft.au=Zhang%2C+Yong&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-90"><a href="#cite_ref-90">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKer_Than2012" class="citation web cs1">Ker Than (30 August 2012). <a rel="nofollow" class="external text" href="https://www.nationalgeographic.com/adventure/article/120829-sugar-space-planets-science-life">"Sugar Found In Space: A Sign of Life?"</a>. National Geographic. Retrieved 4 July 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Sugar+Found+In+Space%3A+A+Sign+of+Life%3F&rft.pub=National+Geographic&rft.date=2012-08-30&rft.au=Ker+Than&rft_id=https%3A%2F%2Fwww.nationalgeographic.com%2Fadventure%2Farticle%2F120829-sugar-space-planets-science-life&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-91"><a href="#cite_ref-91">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJørgensenFavreBisschopBourke2012" class="citation journal cs1">Jørgensen, Jes K.; Favre, Cécile; Bisschop, Suzanne E.; Bourke, Tyler L.; van Dishoeck, Ewine F.; Schmalzl, Markus (September 2012). <a rel="nofollow" class="external text" href="http://www.eso.org/public/archives/releases/sciencepapers/eso1234/eso1234a.pdf">"Detection of the simplest sugar, glycolaldehyde, in a solar-type protostar with ALMA"</a> (PDF). The Astrophysical Journal Letters. 757 (1). L4. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1208.5498">1208.5498</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/2012ApJ...757L...4J">2012ApJ...757L...4J</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%2F2041-8205%2F757%2F1%2FL4">10.1088/2041-8205/757/1/L4</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:14205612">14205612</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=Detection+of+the+simplest+sugar%2C+glycolaldehyde%2C+in+a+solar-type+protostar+with+ALMA&rft.volume=757&rft.issue=1&rft.pages=L4&rft.date=2012-09&rft_id=info%3Aarxiv%2F1208.5498&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A14205612%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1088%2F2041-8205%2F757%2F1%2FL4&rft_id=info%3Abibcode%2F2012ApJ...757L...4J&rft.aulast=J%C3%B8rgensen&rft.aufirst=Jes+K.&rft.au=Favre%2C+C%C3%A9cile&rft.au=Bisschop%2C+Suzanne+E.&rft.au=Bourke%2C+Tyler+L.&rft.au=van+Dishoeck%2C+Ewine+F.&rft.au=Schmalzl%2C+Markus&rft_id=http%3A%2F%2Fwww.eso.org%2Fpublic%2Farchives%2Freleases%2Fsciencepapers%2Feso1234%2Feso1234a.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-ATL-20231205-92"><a href="#cite_ref-ATL-20231205_92-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreen2023" class="citation news cs1">Green, Jaime (5 December 2023). <a rel="nofollow" class="external text" href="https://www.theatlantic.com/science/archive/2023/12/defining-life-existentialism-scientific-theory/676238/">"What Is Life? - The answer matters in space exploration. But we still don't really know"</a>. <a href="/wiki/The_Atlantic" title="The Atlantic">The Atlantic</a>. <a rel="nofollow" class="external text" href="https://archive.today/20231205121742/https://www.theatlantic.com/science/archive/2023/12/defining-life-existentialism-scientific-theory/676238/">Archived</a> from the original on 5 December 2023. Retrieved 15 December 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Atlantic&rft.atitle=What+Is+Life%3F+-+The+answer+matters+in+space+exploration.+But+we+still+don%27t+really+know.&rft.date=2023-12-05&rft.aulast=Green&rft.aufirst=Jaime&rft_id=https%3A%2F%2Fwww.theatlantic.com%2Fscience%2Farchive%2F2023%2F12%2Fdefining-life-existentialism-scientific-theory%2F676238%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NYT-20231214kc-93"><a href="#cite_ref-NYT-20231214kc_93-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChang2023" class="citation news cs1">Chang, Kenneth (14 December 2023). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2023/12/14/science/enceladus-moon-cyanide-life-saturn.html">"Poison Gas Hints at Potential for Life on an Ocean Moon of Saturn - A researcher who has studied the icy world said "the prospects for the development of life are getting better and better on Enceladus.""</a>. <a href="/wiki/The_New_York_Times" title="The New York Times">The New York Times</a>. <a rel="nofollow" class="external text" href="https://archive.today/20231214210144/https://www.nytimes.com/2023/12/14/science/enceladus-moon-cyanide-life-saturn.html">Archived</a> from the original on 14 December 2023. Retrieved 15 December 2023.</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=Poison+Gas+Hints+at+Potential+for+Life+on+an+Ocean+Moon+of+Saturn+-+A+researcher+who+has+studied+the+icy+world+said+%22the+prospects+for+the+development+of+life+are+getting+better+and+better+on+Enceladus.%22&rft.date=2023-12-14&rft.aulast=Chang&rft.aufirst=Kenneth&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2023%2F12%2F14%2Fscience%2Fenceladus-moon-cyanide-life-saturn.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NA-20231214-94"><a href="#cite_ref-NA-20231214_94-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPeter,_Jonah_S.2023" class="citation journal cs1">Peter, Jonah S.; et al. (14 December 2023). <a rel="nofollow" class="external text" href="https://www.nature.com/articles/s41550-023-02160-0">"Detection of HCN and diverse redox chemistry in the plume of Enceladus"</a>. <a href="/wiki/Nature_Astronomy" title="Nature Astronomy">Nature Astronomy</a>. 8 (2): 164–173. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/2301.05259">2301.05259</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/2024NatAs...8..164P">2024NatAs...8..164P</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%2Fs41550-023-02160-0">10.1038/s41550-023-02160-0</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:255825649">255825649</a>. <a rel="nofollow" class="external text" href="https://archive.today/20231215144349/https://www.nature.com/articles/s41550-023-02160-0">Archived</a> from the original on 15 December 2023. Retrieved 15 December 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature+Astronomy&rft.atitle=Detection+of+HCN+and+diverse+redox+chemistry+in+the+plume+of+Enceladus&rft.volume=8&rft.issue=2&rft.pages=164-173&rft.date=2023-12-14&rft_id=info%3Aarxiv%2F2301.05259&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A255825649%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1038%2Fs41550-023-02160-0&rft_id=info%3Abibcode%2F2024NatAs...8..164P&rft.au=Peter%2C+Jonah+S.&rft_id=https%3A%2F%2Fwww.nature.com%2Farticles%2Fs41550-023-02160-0&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-techno-95">^ <a href="#cite_ref-techno_95-0">a</a> <a href="#cite_ref-techno_95-1">b</a> <a href="#cite_ref-techno_95-2">c</a> <a href="#cite_ref-techno_95-3">d</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPat_Brennan" class="citation web cs1">Pat Brennan. <a rel="nofollow" class="external text" href="https://exoplanets.nasa.gov/news/1765/searching-for-signs-of-intelligent-life-technosignatures/">"Searching for Signs of Intelligent Life: Technosignatures"</a>. NASA. Retrieved 4 July 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Searching+for+Signs+of+Intelligent+Life%3A+Technosignatures&rft.pub=NASA&rft.au=Pat+Brennan&rft_id=https%3A%2F%2Fexoplanets.nasa.gov%2Fnews%2F1765%2Fsearching-for-signs-of-intelligent-life-technosignatures%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-96"><a href="#cite_ref-96">^</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.coseti.org/">"The Search for Extraterrestrial Intelligence (SETI) in the Optical Spectrum"</a>. The Columbus <a href="/wiki/Optical_SETI" class="mw-redirect" title="Optical SETI">Optical SETI</a> Observatory.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Search+for+Extraterrestrial+Intelligence+%28SETI%29+in+the+Optical+Spectrum&rft.pub=The+Columbus+Optical+SETI+Observatory&rft_id=http%3A%2F%2Fwww.coseti.org%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 id="CITEREFWhitmireWright1980" class="citation journal cs1">Whitmire, Daniel P.; Wright, David P. (April 1980). "Nuclear waste spectrum as evidence of technological extraterrestrial civilizations". Icarus. 42 (1): 149–156. <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/1980Icar...42..149W">1980Icar...42..149W</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%2F0019-1035%2880%2990253-5">10.1016/0019-1035(80)90253-5</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Icarus&rft.atitle=Nuclear+waste+spectrum+as+evidence+of+technological+extraterrestrial+civilizations&rft.volume=42&rft.issue=1&rft.pages=149-156&rft.date=1980-04&rft_id=info%3Adoi%2F10.1016%2F0019-1035%2880%2990253-5&rft_id=info%3Abibcode%2F1980Icar...42..149W&rft.aulast=Whitmire&rft.aufirst=Daniel+P.&rft.au=Wright%2C+David+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Earth-likeplanet1-98"><a href="#cite_ref-Earth-likeplanet1_98-0">^</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://planet.iap.fr/OB05390.news.html">"Discovery of OGLE 2005-BLG-390Lb, the first cool rocky/icy exoplanet"</a>. IAP.fr. 25 January 2006.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=IAP.fr&rft.atitle=Discovery+of+OGLE+2005-BLG-390Lb%2C+the+first+cool+rocky%2Ficy+exoplanet&rft.date=2006-01-25&rft_id=http%3A%2F%2Fplanet.iap.fr%2FOB05390.news.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-GlieseSpace-99"><a href="#cite_ref-GlieseSpace_99-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFThan2007" class="citation news cs1">Than, Ker (24 April 2007). <a rel="nofollow" class="external text" href="http://www.space.com/3728-major-discovery-planet-harbor-water-life.html">"Major Discovery: New Planet Could Harbor Water and Life"</a>. Space.com.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space.com&rft.atitle=Major+Discovery%3A+New+Planet+Could+Harbor+Water+and+Life&rft.date=2007-04-24&rft.aulast=Than&rft.aufirst=Ker&rft_id=http%3A%2F%2Fwww.space.com%2F3728-major-discovery-planet-harbor-water-life.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Encyclopaedia-100">^ <a href="#cite_ref-Encyclopaedia_100-0">a</a> <a href="#cite_ref-Encyclopaedia_100-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchneider2011" class="citation encyclopaedia cs1">Schneider, Jean (10 September 2011). <a rel="nofollow" class="external text" href="https://exoplanet.eu/catalog/">"Interactive Extra-solar Planets Catalog"</a>. <a href="/wiki/Extrasolar_Planets_Encyclopaedia" title="Extrasolar Planets Encyclopaedia">Extrasolar Planets Encyclopaedia</a>. Retrieved 30 January 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Interactive+Extra-solar+Planets+Catalog&rft.btitle=Extrasolar+Planets+Encyclopaedia&rft.date=2011-09-10&rft.aulast=Schneider&rft.aufirst=Jean&rft_id=https%3A%2F%2Fexoplanet.eu%2Fcatalog%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-101"><a href="#cite_ref-101">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWall2012" class="citation news cs1">Wall, Mike (4 April 2012). <a rel="nofollow" class="external text" href="http://www.space.com/15160-alien-planet-kepler-mission-2016.html">"NASA Extends Planet-Hunting Kepler Mission Through 2016"</a>. Space.com.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space.com&rft.atitle=NASA+Extends+Planet-Hunting+Kepler+Mission+Through+2016&rft.date=2012-04-04&rft.aulast=Wall&rft.aufirst=Mike&rft_id=http%3A%2F%2Fwww.space.com%2F15160-alien-planet-kepler-mission-2016.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-keplersite-102"><a href="#cite_ref-keplersite_102-0">^</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/20131105082102/http://www.nasa.gov/mission_pages/kepler/main/index.html">"NASA – Kepler"</a>. Archived from <a rel="nofollow" class="external text" href="https://www.nasa.gov/mission_pages/kepler/main/index.html">the original</a> on 5 November 2013. Retrieved 4 November 2013.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NASA+%E2%80%93+Kepler&rft_id=http%3A%2F%2Fwww.nasa.gov%2Fmission_pages%2Fkepler%2Fmain%2Findex.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-usher-103"><a href="#cite_ref-usher_103-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHarringtonJohnson2013" class="citation web cs1">Harrington, J. D.; Johnson, M. (4 November 2013). <a rel="nofollow" class="external text" href="https://www.nasa.gov/press/2013/november/nasa-kepler-results-usher-in-a-new-era-of-astronomy/">"NASA Kepler Results Usher in a New Era of Astronomy"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NASA+Kepler+Results+Usher+in+a+New+Era+of+Astronomy&rft.date=2013-11-04&rft.aulast=Harrington&rft.aufirst=J.+D.&rft.au=Johnson%2C+M.&rft_id=http%3A%2F%2Fwww.nasa.gov%2Fpress%2F2013%2Fnovember%2Fnasa-kepler-results-usher-in-a-new-era-of-astronomy%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-104"><a href="#cite_ref-104">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTenenbaumJenkinsSeaderBurke2013" class="citation journal cs1">Tenenbaum, P.; Jenkins, J. M.; Seader, S.; Burke, C. J.; Christiansen, J. L.; Rowe, J. F.; Caldwell, D. A.; Clarke, B. D.; Li, J.; Quintana, E. V.; Smith, J. C.; Thompson, S. E.; Twicken, J. D.; Borucki, W. J.; Batalha, N. M.; Cote, M. T.; Haas, M. R.; Hunter, R. C.; Sanderfer, D. T.; Girouard, F. R.; Hall, J. R.; Ibrahim, K.; Klaus, T. C.; McCauliff, S. D.; Middour, C. K.; Sabale, A.; Uddin, A. K.; Wohler, B.; Barclay, T.; Still, M. (2013). "Detection of Potential Transit Signals in the First 12 Quarters of Kepler Mission Data". The Astrophysical Journal Supplement Series. 206 (1): 5. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1212.2915">1212.2915</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/2013ApJS..206....5T">2013ApJS..206....5T</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%2F0067-0049%2F206%2F1%2F5">10.1088/0067-0049/206/1/5</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:250885680">250885680</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+Supplement+Series&rft.atitle=Detection+of+Potential+Transit+Signals+in+the+First+12+Quarters+of+Kepler+Mission+Data&rft.volume=206&rft.issue=1&rft.pages=5&rft.date=2013&rft_id=info%3Aarxiv%2F1212.2915&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A250885680%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1088%2F0067-0049%2F206%2F1%2F5&rft_id=info%3Abibcode%2F2013ApJS..206....5T&rft.aulast=Tenenbaum&rft.aufirst=P.&rft.au=Jenkins%2C+J.+M.&rft.au=Seader%2C+S.&rft.au=Burke%2C+C.+J.&rft.au=Christiansen%2C+J.+L.&rft.au=Rowe%2C+J.+F.&rft.au=Caldwell%2C+D.+A.&rft.au=Clarke%2C+B.+D.&rft.au=Li%2C+J.&rft.au=Quintana%2C+E.+V.&rft.au=Smith%2C+J.+C.&rft.au=Thompson%2C+S.+E.&rft.au=Twicken%2C+J.+D.&rft.au=Borucki%2C+W.+J.&rft.au=Batalha%2C+N.+M.&rft.au=Cote%2C+M.+T.&rft.au=Haas%2C+M.+R.&rft.au=Hunter%2C+R.+C.&rft.au=Sanderfer%2C+D.+T.&rft.au=Girouard%2C+F.+R.&rft.au=Hall%2C+J.+R.&rft.au=Ibrahim%2C+K.&rft.au=Klaus%2C+T.+C.&rft.au=McCauliff%2C+S.+D.&rft.au=Middour%2C+C.+K.&rft.au=Sabale%2C+A.&rft.au=Uddin%2C+A.+K.&rft.au=Wohler%2C+B.&rft.au=Barclay%2C+T.&rft.au=Still%2C+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-mygoditsfullofplanets-105"><a href="#cite_ref-mygoditsfullofplanets_105-0">^</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://web.archive.org/web/20150725135354/http://phl.upr.edu/press-releases/mygoditsfullofplanetstheyshouldhavesentapoet">"My God, it's full of planets! They should have sent a poet"</a> (Press release). Planetary Habitability Laboratory, University of Puerto Rico at Arecibo. 3 January 2012. Archived from <a rel="nofollow" class="external text" href="https://phl.upr.edu/press-releases/mygoditsfullofplanetstheyshouldhavesentapoet">the original</a> on 25 July 2015. Retrieved 25 July 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=My+God%2C+it%27s+full+of+planets%21+They+should+have+sent+a+poet.&rft.pub=Planetary+Habitability+Laboratory%2C+University+of+Puerto+Rico+at+Arecibo&rft.date=2012-01-03&rft_id=http%3A%2F%2Fphl.upr.edu%2Fpress-releases%2Fmygoditsfullofplanetstheyshouldhavesentapoet&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-106"><a href="#cite_ref-106">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSanterneDíazAlmenaraLethuillier2013" class="citation journal cs1">Santerne, A.; Díaz, R. F.; Almenara, J.-M.; Lethuillier, A.; Deleuil, M.; Moutou, C. (2013). "Astrophysical false positives in exoplanet transit surveys: Why do we need bright stars?". Sf2A-2013: Proceedings of the Annual Meeting of the French Society of Astronomy and Astrophysics: 555. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1310.2133">1310.2133</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/2013sf2a.conf..555S">2013sf2a.conf..555S</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Sf2A-2013%3A+Proceedings+of+the+Annual+Meeting+of+the+French+Society+of+Astronomy+and+Astrophysics&rft.atitle=Astrophysical+false+positives+in+exoplanet+transit+surveys%3A+Why+do+we+need+bright+stars%3F&rft.pages=555&rft.date=2013&rft_id=info%3Aarxiv%2F1310.2133&rft_id=info%3Abibcode%2F2013sf2a.conf..555S&rft.aulast=Santerne&rft.aufirst=A.&rft.au=D%C3%ADaz%2C+R.+F.&rft.au=Almenara%2C+J.-M.&rft.au=Lethuillier%2C+A.&rft.au=Deleuil%2C+M.&rft.au=Moutou%2C+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Nature-20120111-107"><a href="#cite_ref-Nature-20120111_107-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCassanKubasBeaulieuDominik2012" class="citation journal cs1">Cassan, A.; et al. (11 January 2012). "One or more bound planets per Milky Way star from microlensing observations". Nature. 481 (7380): 167–169. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1202.0903">1202.0903</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/2012Natur.481..167C">2012Natur.481..167C</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%2Fnature10684">10.1038/nature10684</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/22237108">22237108</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:2614136">2614136</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=One+or+more+bound+planets+per+Milky+Way+star+from+microlensing+observations&rft.volume=481&rft.issue=7380&rft.pages=167-169&rft.date=2012-01-11&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A2614136%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2012Natur.481..167C&rft_id=info%3Aarxiv%2F1202.0903&rft_id=info%3Apmid%2F22237108&rft_id=info%3Adoi%2F10.1038%2Fnature10684&rft.aulast=Cassan&rft.aufirst=A.&rft.au=Kubas%2C+D.&rft.au=Beaulieu%2C+J.+-P.&rft.au=Dominik%2C+M.&rft.au=Horne%2C+K.&rft.au=Greenhill%2C+J.&rft.au=Wambsganss%2C+J.&rft.au=Menzies%2C+J.&rft.au=Williams%2C+A.&rft.au=J%C3%B8rgensen%2C+U.+G.&rft.au=Udalski%2C+A.&rft.au=Bennett%2C+D.+P.&rft.au=Albrow%2C+M.+D.&rft.au=Batista%2C+V.&rft.au=Brillant%2C+S.&rft.au=Caldwell%2C+J.+A.+R.&rft.au=Cole%2C+A.&rft.au=Coutures%2C+C.&rft.au=Cook%2C+K.+H.&rft.au=Dieters%2C+S.&rft.au=Prester%2C+D.+D.&rft.au=Donatowicz%2C+J.&rft.au=Fouqu%C3%A9%2C+P.&rft.au=Hill%2C+K.&rft.au=Kains%2C+N.&rft.au=Kane%2C+S.&rft.au=Marquette%2C+J.+-B.&rft.au=Martin%2C+R.&rft.au=Pollard%2C+K.+R.&rft.au=Sahu%2C+K.+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-ucb1in5-111"><a href="#cite_ref-ucb1in5_111-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSanders2013" class="citation web cs1">Sanders, R. (4 November 2013). <a rel="nofollow" class="external text" href="http://newscenter.berkeley.edu/2013/11/04/astronomers-answer-key-question-how-common-are-habitable-planets/">"Astronomers answer key question: How common are habitable planets?"</a>. newscenter.berkeley.edu.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=newscenter.berkeley.edu&rft.atitle=Astronomers+answer+key+question%3A+How+common+are+habitable+planets%3F&rft.date=2013-11-04&rft.aulast=Sanders&rft.aufirst=R.&rft_id=http%3A%2F%2Fnewscenter.berkeley.edu%2F2013%2F11%2F04%2Fastronomers-answer-key-question-how-common-are-habitable-planets%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-earthsunhzprev-112"><a href="#cite_ref-earthsunhzprev_112-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPetiguraHowardMarcy2013" class="citation journal cs1">Petigura, E. A.; Howard, A. W.; Marcy, G. W. (2013). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3845182">"Prevalence of Earth-size planets orbiting Sun-like stars"</a>. <a href="/wiki/Proceedings_of_the_National_Academy_of_Sciences" class="mw-redirect" title="Proceedings of the National Academy of Sciences">Proceedings of the National Academy of Sciences</a>. 110 (48): 19273–19278. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1311.6806">1311.6806</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/2013PNAS..11019273P">2013PNAS..11019273P</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1073%2Fpnas.1319909110">10.1073/pnas.1319909110</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3845182">3845182</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/24191033">24191033</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+National+Academy+of+Sciences&rft.atitle=Prevalence+of+Earth-size+planets+orbiting+Sun-like+stars&rft.volume=110&rft.issue=48&rft.pages=19273-19278&rft.date=2013&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3845182%23id-name%3DPMC&rft_id=info%3Abibcode%2F2013PNAS..11019273P&rft_id=info%3Aarxiv%2F1311.6806&rft_id=info%3Apmid%2F24191033&rft_id=info%3Adoi%2F10.1073%2Fpnas.1319909110&rft.aulast=Petigura&rft.aufirst=E.+A.&rft.au=Howard%2C+A.+W.&rft.au=Marcy%2C+G.+W.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3845182&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-114"><a href="#cite_ref-114">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKhan2013" class="citation news cs1">Khan, Amina (4 November 2013). <a rel="nofollow" class="external text" href="https://www.latimes.com/science/la-sci-earth-like-planets-20131105,0,2673237.story">"Milky Way may host billions of Earth-size planets"</a>. <a href="/wiki/Los_Angeles_Times" title="Los Angeles Times">Los Angeles Times</a>. Retrieved 5 November 2013.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Los+Angeles+Times&rft.atitle=Milky+Way+may+host+billions+of+Earth-size+planets&rft.date=2013-11-04&rft.aulast=Khan&rft.aufirst=Amina&rft_id=https%3A%2F%2Fwww.latimes.com%2Fscience%2Fla-sci-earth-like-planets-20131105%2C0%2C2673237.story&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-115"><a href="#cite_ref-115">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStrigariBarnabèMarshallBlandford2012" class="citation journal cs1">Strigari, L. E.; Barnabè, M.; Marshall, P. J.; Blandford, R. D. (2012). <a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1365-2966.2012.21009.x">"Nomads of the Galaxy"</a>. <a href="/wiki/Monthly_Notices_of_the_Royal_Astronomical_Society" title="Monthly Notices of the Royal Astronomical Society">Monthly Notices of the Royal Astronomical Society</a>. 423 (2): 1856–1865. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1201.2687">1201.2687</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/2012MNRAS.423.1856S">2012MNRAS.423.1856S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1365-2966.2012.21009.x">10.1111/j.1365-2966.2012.21009.x</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:119185094">119185094</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Monthly+Notices+of+the+Royal+Astronomical+Society&rft.atitle=Nomads+of+the+Galaxy&rft.volume=423&rft.issue=2&rft.pages=1856-1865&rft.date=2012&rft_id=info%3Aarxiv%2F1201.2687&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119185094%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1111%2Fj.1365-2966.2012.21009.x&rft_id=info%3Abibcode%2F2012MNRAS.423.1856S&rft.aulast=Strigari&rft.aufirst=L.+E.&rft.au=Barnab%C3%A8%2C+M.&rft.au=Marshall%2C+P.+J.&rft.au=Blandford%2C+R.+D.&rft_id=https%3A%2F%2Fdoi.org%2F10.1111%252Fj.1365-2966.2012.21009.x&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> estimates 700 objects >10−6 solar masses (roughly the mass of Mars) per main-sequence star between 0.08 and 1 Solar mass, of which there are billions in the Milky Way. </li> <li id="cite_note-nyt20160824-116"><a href="#cite_ref-nyt20160824_116-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChang2016" class="citation news cs1">Chang, Kenneth (24 August 2016). <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2016/08/25/science/earth-planet-proxima-centauri.html">"One Star Over, a Planet That Might Be Another Earth"</a>. The New York Times. Archived from <a rel="nofollow" class="external text" href="https://www.nytimes.com/2016/08/25/science/earth-planet-proxima-centauri.html">the original</a> on 1 January 2022. Retrieved 4 September 2016.</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=One+Star+Over%2C+a+Planet+That+Might+Be+Another+Earth&rft.date=2016-08-24&rft.aulast=Chang&rft.aufirst=Kenneth&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2016%2F08%2F25%2Fscience%2Fearth-planet-proxima-centauri.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-CT-Exo-2014-117"><a href="#cite_ref-CT-Exo-2014_117-0">^</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://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=DENIS-P+J082303.1-491201+b&type=CONFIRMED_PLANET">"DENIS-P J082303.1-491201 b"</a>. <a href="/wiki/Caltech" class="mw-redirect" title="Caltech">Caltech</a>. Retrieved 8 March 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Caltech&rft.atitle=DENIS-P+J082303.1-491201+b&rft_id=http%3A%2F%2Fexoplanetarchive.ipac.caltech.edu%2Fcgi-bin%2FDisplayOverview%2Fnph-DisplayOverview%3Fobjname%3DDENIS-P%2BJ082303.1-491201%2Bb%26type%3DCONFIRMED_PLANET&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-HU-201308-118"><a href="#cite_ref-HU-201308_118-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSahlmannLazorenkoSégransanMartín2013" class="citation journal cs1">Sahlmann, J.; Lazorenko, P. F.; Ségransan, D.; Martín, Eduardo L.; Queloz, D.; Mayor, M.; Udry, S. (August 2013). "Astrometric orbit of a low-mass companion to an ultracool dwarf". Astronomy & Astrophysics. 556: 133. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1306.3225">1306.3225</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/2013A&A...556A.133S">2013A&A...556A.133S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1051%2F0004-6361%2F201321871">10.1051/0004-6361/201321871</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:119193690">119193690</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomy+%26+Astrophysics&rft.atitle=Astrometric+orbit+of+a+low-mass+companion+to+an+ultracool+dwarf&rft.volume=556&rft.pages=133&rft.date=2013-08&rft_id=info%3Aarxiv%2F1306.3225&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A119193690%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1051%2F0004-6361%2F201321871&rft_id=info%3Abibcode%2F2013A%26A...556A.133S&rft.aulast=Sahlmann&rft.aufirst=J.&rft.au=Lazorenko%2C+P.+F.&rft.au=S%C3%A9gransan%2C+D.&rft.au=Mart%C3%ADn%2C+Eduardo+L.&rft.au=Queloz%2C+D.&rft.au=Mayor%2C+M.&rft.au=Udry%2C+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-hscfa20130225-119"><a href="#cite_ref-hscfa20130225_119-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAguilarPulliam2013" class="citation web cs1">Aguilar, David A.; Pulliam, Christine (25 February 2013). <a rel="nofollow" class="external text" href="https://www.cfa.harvard.edu/news/2013-06">"Future Evidence for Extraterrestrial Life Might Come from Dying Stars"</a>. Harvard-Smithsonian Center for Astrophysics. Release 2013-06. Retrieved 9 June 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Future+Evidence+for+Extraterrestrial+Life+Might+Come+from+Dying+Stars&rft.pub=Harvard-Smithsonian+Center+for+Astrophysics&rft.date=2013-02-25&rft.aulast=Aguilar&rft.aufirst=David+A.&rft.au=Pulliam%2C+Christine&rft_id=https%3A%2F%2Fwww.cfa.harvard.edu%2Fnews%2F2013-06&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-120"><a href="#cite_ref-120">^</a> Bennett, pp. 16-23 </li> <li id="cite_note-crowe1999-121"><a href="#cite_ref-crowe1999_121-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrowe1999" class="citation book cs1">Crowe, Michael J. (1999). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=J4TZPlihVUoC">The Extraterrestrial Life Debate, 1750–1900</a>. Courier Dover Publications. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-486-40675-6" title="Special:BookSources/978-0-486-40675-6"><bdi>978-0-486-40675-6</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+Extraterrestrial+Life+Debate%2C+1750%E2%80%931900&rft.pub=Courier+Dover+Publications&rft.date=1999&rft.isbn=978-0-486-40675-6&rft.aulast=Crowe&rft.aufirst=Michael+J.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DJ4TZPlihVUoC&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-122"><a href="#cite_ref-122">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWiker2002" class="citation web cs1">Wiker, Benjamin D. (4 November 2002). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20030210140752/http://www.crisismagazine.com/november2002/feature7.htm">"Alien Ideas: Christianity and the Search for Extraterrestrial Life"</a>. Crisis Magazine. Archived from <a rel="nofollow" class="external text" href="http://www.crisismagazine.com/november2002/feature7.htm">the original</a> on 10 February 2003.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Crisis+Magazine&rft.atitle=Alien+Ideas%3A+Christianity+and+the+Search+for+Extraterrestrial+Life&rft.date=2002-11-04&rft.aulast=Wiker&rft.aufirst=Benjamin+D.&rft_id=http%3A%2F%2Fwww.crisismagazine.com%2Fnovember2002%2Ffeature7.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Irwin-123"><a href="#cite_ref-Irwin_123-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIrwin2003" class="citation book cs1">Irwin, Robert (2003). The Arabian Nights: A Companion. <a href="/wiki/I.B._Tauris" title="I.B. Tauris">Tauris Parke Paperbacks</a>. p. 204 & 209. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-86064-983-7" title="Special:BookSources/978-1-86064-983-7"><bdi>978-1-86064-983-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Arabian+Nights%3A+A+Companion&rft.pages=204+%26+209&rft.pub=Tauris+Parke+Paperbacks&rft.date=2003&rft.isbn=978-1-86064-983-7&rft.aulast=Irwin&rft.aufirst=Robert&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Weintraub-124"><a href="#cite_ref-Weintraub_124-0">^</a> David A. Weintraub (2014). "Islam," Religions and Extraterrestrial Life (pp 161–168). Springer International Publishing. </li> <li id="cite_note-Gabrovsky_2016_p._83-125"><a href="#cite_ref-Gabrovsky_2016_p._83_125-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGabrovsky2016" class="citation book cs1">Gabrovsky, A.N. (2016). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=3JqkCgAAQBAJ&pg=PT83">Chaucer the Alchemist: Physics, Mutability, and the Medieval Imagination</a>. The New Middle Ages. Palgrave Macmillan US. p. 83. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-137-52391-4" title="Special:BookSources/978-1-137-52391-4"><bdi>978-1-137-52391-4</bdi></a>. Retrieved 14 May 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Chaucer+the+Alchemist%3A+Physics%2C+Mutability%2C+and+the+Medieval+Imagination&rft.series=The+New+Middle+Ages&rft.pages=83&rft.pub=Palgrave+Macmillan+US&rft.date=2016&rft.isbn=978-1-137-52391-4&rft.aulast=Gabrovsky&rft.aufirst=A.N.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D3JqkCgAAQBAJ%26pg%3DPT83&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-126"><a href="#cite_ref-126">^</a> Crowe, p. 4 </li> <li id="cite_note-127"><a href="#cite_ref-127">^</a> Bennett, p. 24 </li> <li id="cite_note-Bennet31-128"><a href="#cite_ref-Bennet31_128-0">^</a> Bennett, p. 31 </li> <li id="cite_note-Anaxagoras-129">^ <a href="#cite_ref-Anaxagoras_129-0">a</a> <a href="#cite_ref-Anaxagoras_129-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJ._William_Schopf2002" class="citation book cs1">J. William Schopf (2002). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=dhcQuqC8Y3kC&dq=panspermia+anaxagoras&pg=PA14">Life's Origin: The Beginnings of Biological Evolution</a>. University of California Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780520233911" title="Special:BookSources/9780520233911"><bdi>9780520233911</bdi></a>. Retrieved 6 August 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Life%27s+Origin%3A+The+Beginnings+of+Biological+Evolution&rft.pub=University+of+California+Press&rft.date=2002&rft.isbn=9780520233911&rft.au=J.+William+Schopf&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DdhcQuqC8Y3kC%26dq%3Dpanspermia%2Banaxagoras%26pg%3DPA14&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-130"><a href="#cite_ref-130">^</a> Bennet, pp. 24-27 </li> <li id="cite_note-131"><a href="#cite_ref-131">^</a> Bennet, p. 5 </li> <li id="cite_note-132"><a href="#cite_ref-132">^</a> Bennett, p. 29 </li> <li id="cite_note-133"><a href="#cite_ref-133">^</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/20141013120648/http://www.positiveatheism.org/hist/brunoiuw0.htm#IUW0III">"Giordano Bruno: On the Infinite Universe and Worlds (De l'Infinito Universo et Mondi) Introductory Epistle: Argument of the Third Dialogue"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.positiveatheism.org/hist/brunoiuw0.htm#IUW0III">the original</a> on 13 October 2014. Retrieved 4 October 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Giordano+Bruno%3A+On+the+Infinite+Universe+and+Worlds+%28De+l%27Infinito+Universo+et+Mondi%29+Introductory+Epistle%3A+Argument+of+the+Third+Dialogue&rft_id=http%3A%2F%2Fwww.positiveatheism.org%2Fhist%2Fbrunoiuw0.htm%23IUW0III&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-AM8-134">^ <a href="#cite_ref-AM8_134-0">a</a> <a href="#cite_ref-AM8_134-1">b</a> Aguilera Mochon, p. 8 </li> <li id="cite_note-135"><a href="#cite_ref-135">^</a> Bennet, p. 30 </li> <li id="cite_note-136"><a href="#cite_ref-136">^</a> Bennet, pp. 30-32 </li> <li id="cite_note-137"><a href="#cite_ref-137">^</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.loc.gov/collections/finding-our-place-in-the-cosmos-with-carl-sagan/articles-and-essays/life-on-other-worlds/peoples-and-creatures-of-the-moon">"Peoples & Creatures of the Moon | Life on Other Worlds | Articles and Essays | Finding Our Place in the Cosmos: From Galileo to Sagan and Beyond | Digital Collections | Library of Congress"</a>. Library of Congress, Washington, D.C. 20540 USA. Retrieved 10 May 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Library+of+Congress%2C+Washington%2C+D.C.+20540+USA&rft.atitle=Peoples+%26+Creatures+of+the+Moon+%7C+Life+on+Other+Worlds+%7C+Articles+and+Essays+%7C+Finding+Our+Place+in+the+Cosmos%3A+From+Galileo+to+Sagan+and+Beyond+%7C+Digital+Collections+%7C+Library+of+Congress&rft_id=https%3A%2F%2Fwww.loc.gov%2Fcollections%2Ffinding-our-place-in-the-cosmos-with-carl-sagan%2Farticles-and-essays%2Flife-on-other-worlds%2Fpeoples-and-creatures-of-the-moon&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-138"><a href="#cite_ref-138">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFParkyn2019" class="citation web cs1">Parkyn, Joel L. (April 2019). <a rel="nofollow" class="external text" href="https://ore.exeter.ac.uk/repository/bitstream/handle/10871/120770/ParkynJ.pdf?sequence=2">"The Devine Pedagogy: Theological Explorations of Intelligent Extraterrestrial Life"</a> (PDF). ore.exeter.ac.uk. Retrieved 10 May 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=ore.exeter.ac.uk&rft.atitle=The+Devine+Pedagogy%3A+Theological+Explorations+of+Intelligent+Extraterrestrial+Life&rft.date=2019-04&rft.aulast=Parkyn&rft.aufirst=Joel+L.&rft_id=https%3A%2F%2Fore.exeter.ac.uk%2Frepository%2Fbitstream%2Fhandle%2F10871%2F120770%2FParkynJ.pdf%3Fsequence%3D2&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-139"><a href="#cite_ref-139">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFEvansMaunder1903" class="citation journal cs1">Evans, J. E.; <a href="/wiki/Edward_Walter_Maunder" title="Edward Walter Maunder">Maunder, E. W.</a> (June 1903). <a rel="nofollow" class="external text" href="https://zenodo.org/record/1431867">"Experiments as to the actuality of the "Canals" observed on Mars"</a>. Monthly Notices of the Royal Astronomical Society. 63 (8): 488–499. <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/1903MNRAS..63..488E">1903MNRAS..63..488E</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fmnras%2F63.8.488">10.1093/mnras/63.8.488</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Monthly+Notices+of+the+Royal+Astronomical+Society&rft.atitle=Experiments+as+to+the+actuality+of+the+%22Canals%22+observed+on+Mars&rft.volume=63&rft.issue=8&rft.pages=488-499&rft.date=1903-06&rft_id=info%3Adoi%2F10.1093%2Fmnras%2F63.8.488&rft_id=info%3Abibcode%2F1903MNRAS..63..488E&rft.aulast=Evans&rft.aufirst=J.+E.&rft.au=Maunder%2C+E.+W.&rft_id=https%3A%2F%2Fzenodo.org%2Frecord%2F1431867&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-Wallace1907-140"><a href="#cite_ref-Wallace1907_140-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWallace1907" class="citation book cs1">Wallace, Alfred Russel (1907). <a rel="nofollow" class="external text" href="http://people.wku.edu/charles.smith/wallace/S730.htm">Is Mars Habitable? A Critical Examination of Professor Lowell's Book "Mars and Its Canals," With an Alternative Explanation</a>. London: Macmillan. <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/8257449">8257449</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Is+Mars+Habitable%3F+A+Critical+Examination+of+Professor+Lowell%27s+Book+%22Mars+and+Its+Canals%2C%22+With+an+Alternative+Explanation&rft.place=London&rft.pub=Macmillan&rft.date=1907&rft_id=info%3Aoclcnum%2F8257449&rft.aulast=Wallace&rft.aufirst=Alfred+Russel&rft_id=http%3A%2F%2Fpeople.wku.edu%2Fcharles.smith%2Fwallace%2FS730.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-chambers-141"><a href="#cite_ref-chambers_141-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFChambers1999" class="citation book cs1">Chambers, Paul (1999). <a rel="nofollow" class="external text" href="https://archive.org/details/lifeonmarscomple00cham">Life on Mars; The Complete Story</a>. London: Blandford. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7137-2747-0" title="Special:BookSources/978-0-7137-2747-0"><bdi>978-0-7137-2747-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Life+on+Mars%3B+The+Complete+Story&rft.place=London&rft.pub=Blandford&rft.date=1999&rft.isbn=978-0-7137-2747-0&rft.aulast=Chambers&rft.aufirst=Paul&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Flifeonmarscomple00cham&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.loc.gov/collections/finding-our-place-in-the-cosmos-with-carl-sagan/articles-and-essays/life-on-other-worlds/seeing-and-interpreting-martian-oceans-and-canals">"Seeing and Interpreting Martian Oceans and Canals | Life on Other Worlds | Articles and Essays | Finding Our Place in the Cosmos: From Galileo to Sagan and Beyond | Digital Collections | Library of Congress"</a>. Library of Congress, Washington, D.C. 20540 USA. Retrieved 10 May 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Library+of+Congress%2C+Washington%2C+D.C.+20540+USA&rft.atitle=Seeing+and+Interpreting+Martian+Oceans+and+Canals+%7C+Life+on+Other+Worlds+%7C+Articles+and+Essays+%7C+Finding+Our+Place+in+the+Cosmos%3A+From+Galileo+to+Sagan+and+Beyond+%7C+Digital+Collections+%7C+Library+of+Congress&rft_id=https%3A%2F%2Fwww.loc.gov%2Fcollections%2Ffinding-our-place-in-the-cosmos-with-carl-sagan%2Farticles-and-essays%2Flife-on-other-worlds%2Fseeing-and-interpreting-martian-oceans-and-canals&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-143"><a href="#cite_ref-143">^</a> Aguilera Mochon, pp. 8–9 </li> <li id="cite_note-144"><a href="#cite_ref-144">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBerzelius1834" class="citation journal cs1"><a href="/wiki/J%C3%B6ns_Jacob_Berzelius" title="Jöns Jacob Berzelius">Berzelius, Jöns Jacob</a> (1834). "Analysis of the Alais meteorite and implications about life in other worlds". <a href="/wiki/Liebigs_Annalen" title="Liebigs Annalen">Annalen der Chemie und Pharmacie</a>. 10: 134–135.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annalen+der+Chemie+und+Pharmacie&rft.atitle=Analysis+of+the+Alais+meteorite+and+implications+about+life+in+other+worlds&rft.volume=10&rft.pages=134-135&rft.date=1834&rft.aulast=Berzelius&rft.aufirst=J%C3%B6ns+Jacob&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </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="CITEREFThomson1871" class="citation journal cs1"><a href="/wiki/William_Thomson,_1st_Baron_Kelvin" class="mw-redirect" title="William Thomson, 1st Baron Kelvin">Thomson, William</a> (August 1871). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2070380">"The British Association Meeting at Edinburgh"</a>. Nature. 4 (92): 261–278. <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/1871Natur...4..261.">1871Natur...4..261.</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%2F004261a0">10.1038/004261a0</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2070380">2070380</a>. <q>We must regard it as probably to the highest degree that there are countless seed-bearing meteoritic stones moving through space.</q></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+British+Association+Meeting+at+Edinburgh&rft.volume=4&rft.issue=92&rft.pages=261-278&rft.date=1871-08&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2070380%23id-name%3DPMC&rft_id=info%3Adoi%2F10.1038%2F004261a0&rft_id=info%3Abibcode%2F1871Natur...4..261.&rft.aulast=Thomson&rft.aufirst=William&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2070380&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </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="CITEREFDemets2012" class="citation journal cs1">Demets, René (October 2012). "Darwin's Contribution to the Development of the Panspermia Theory". Astrobiology. 12 (10): 946–950. <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/2012AsBio..12..946D">2012AsBio..12..946D</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1089%2Fast.2011.0790">10.1089/ast.2011.0790</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/23078643">23078643</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astrobiology&rft.atitle=Darwin%27s+Contribution+to+the+Development+of+the+Panspermia+Theory&rft.volume=12&rft.issue=10&rft.pages=946-950&rft.date=2012-10&rft_id=info%3Apmid%2F23078643&rft_id=info%3Adoi%2F10.1089%2Fast.2011.0790&rft_id=info%3Abibcode%2F2012AsBio..12..946D&rft.aulast=Demets&rft.aufirst=Ren%C3%A9&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-147"><a href="#cite_ref-147">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFArrhenius1908" class="citation book cs1">Arrhenius, Svante (March 1908). <a rel="nofollow" class="external text" href="https://archive.org/details/worldsinmakingev00arrhrich">Worlds in the Making: The Evolution of the Universe</a>. trans. H. Borns. Harper & Brothers. <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/1935295">1935295</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Worlds+in+the+Making%3A+The+Evolution+of+the+Universe&rft.pub=Harper+%26+Brothers&rft.date=1908-03&rft_id=info%3Aoclcnum%2F1935295&rft.aulast=Arrhenius&rft.aufirst=Svante&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fworldsinmakingev00arrhrich&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-148"><a href="#cite_ref-148">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNola_Taylor_Tillman2012" class="citation web cs1">Nola Taylor Tillman (20 August 2012). <a rel="nofollow" class="external text" href="https://www.space.com/17191-face-on-mars.html">"The Face on Mars: Fact & Fiction"</a>. Space.com. Retrieved 18 September 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Face+on+Mars%3A+Fact+%26+Fiction&rft.pub=Space.com&rft.date=2012-08-20&rft.au=Nola+Taylor+Tillman&rft_id=https%3A%2F%2Fwww.space.com%2F17191-face-on-mars.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-149"><a href="#cite_ref-149">^</a> Aguilera Mochon, pp. 10–11 </li> <li id="cite_note-150"><a href="#cite_ref-150">^</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/20180526161726/https://www.nasa.gov/vision/universe/starsgalaxies/life%27s_working_definition.html">"Life's Working Definition: Does It Work?"</a>. NASA. 2002. Archived from <a rel="nofollow" class="external text" href="https://www.nasa.gov/vision/universe/starsgalaxies/life%27s_working_definition.html">the original</a> on 26 May 2018. Retrieved 17 January 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Life%27s+Working+Definition%3A+Does+It+Work%3F&rft.pub=NASA&rft.date=2002&rft_id=https%3A%2F%2Fwww.nasa.gov%2Fvision%2Funiverse%2Fstarsgalaxies%2Flife%2527s_working_definition.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-151"><a href="#cite_ref-151">^</a> Aguilera Mochon, p. 10 </li> <li id="cite_note-152"><a href="#cite_ref-152">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCross2004" class="citation journal cs1">Cross, Anne (2004). "The Flexibility of Scientific Rhetoric: A Case Study of UFO Researchers". Qualitative Sociology. 27 (1): 3–34. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1023%2FB%3AQUAS.0000015542.28438.41">10.1023/B:QUAS.0000015542.28438.41</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:144197172">144197172</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Qualitative+Sociology&rft.atitle=The+Flexibility+of+Scientific+Rhetoric%3A+A+Case+Study+of+UFO+Researchers&rft.volume=27&rft.issue=1&rft.pages=3-34&rft.date=2004&rft_id=info%3Adoi%2F10.1023%2FB%3AQUAS.0000015542.28438.41&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A144197172%23id-name%3DS2CID&rft.aulast=Cross&rft.aufirst=Anne&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFAilleris2011" class="citation journal cs1">Ailleris, Philippe (January–February 2011). "The lure of local SETI: Fifty years of field experiments". Acta Astronautica. 68 (1–2): 2–15. <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/2011AcAau..68....2A">2011AcAau..68....2A</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%2Fj.actaastro.2009.12.011">10.1016/j.actaastro.2009.12.011</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Acta+Astronautica&rft.atitle=The+lure+of+local+SETI%3A+Fifty+years+of+field+experiments&rft.volume=68&rft.issue=1%E2%80%932&rft.pages=2-15&rft.date=2011-01%2F2011-02&rft_id=info%3Adoi%2F10.1016%2Fj.actaastro.2009.12.011&rft_id=info%3Abibcode%2F2011AcAau..68....2A&rft.aulast=Ailleris&rft.aufirst=Philippe&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-154"><a href="#cite_ref-154">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBeck1971" class="citation journal cs1">Beck, Lewis White (1971). <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/3129745">"Extraterrestrial Intelligent Life"</a>. Proceedings and Addresses of the American Philosophical Association. 45: 5–21. <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%2F3129745">10.2307/3129745</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/3129745">3129745</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+and+Addresses+of+the+American+Philosophical+Association&rft.atitle=Extraterrestrial+Intelligent+Life&rft.volume=45&rft.pages=5-21&rft.date=1971&rft_id=info%3Adoi%2F10.2307%2F3129745&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F3129745%23id-name%3DJSTOR&rft.aulast=Beck&rft.aufirst=Lewis+White&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F3129745&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-155"><a href="#cite_ref-155">^</a> Bennett, p. 4 </li> <li id="cite_note-156"><a href="#cite_ref-156">^</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://antarcticaedu.com/bio2024.htm">"LECTURE 4: MODERN THOUGHTS ON EXTRATERRESTRIAL LIFE"</a>. The University of Antarctica. Retrieved 25 July 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+University+of+Antarctica&rft.atitle=LECTURE+4%3A+MODERN+THOUGHTS+ON+EXTRATERRESTRIAL+LIFE&rft_id=http%3A%2F%2Fantarcticaedu.com%2Fbio2024.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://earthsky.org/space/source-of-wow-signal-in-1977-sunlike-star-2mass-19281982-2640123/">"Did the Wow! signal come from this star? | Space | EarthSky"</a>. earthsky.org. 2 December 2020. Retrieved 10 May 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=earthsky.org&rft.atitle=Did+the+Wow%21+signal+come+from+this+star%3F+%7C+Space+%7C+EarthSky&rft.date=2020-12-02&rft_id=https%3A%2F%2Fearthsky.org%2Fspace%2Fsource-of-wow-signal-in-1977-sunlike-star-2mass-19281982-2640123%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFPaul_Davies2016" class="citation web cs1">Paul Davies (1 September 2016). <a rel="nofollow" class="external text" href="https://www.scientificamerican.com/article/the-cosmos-might-be-mostly-devoid-of-life/">"The Cosmos Might Be Mostly Devoid of Life"</a>. Scientific American. Retrieved 8 July 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Cosmos+Might+Be+Mostly+Devoid+of+Life&rft.pub=Scientific+American&rft.date=2016-09-01&rft.au=Paul+Davies&rft_id=https%3A%2F%2Fwww.scientificamerican.com%2Farticle%2Fthe-cosmos-might-be-mostly-devoid-of-life%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFWardBrownlee2000" class="citation book cs1">Ward, Peter; Brownlee, Donald (2000). Rare Earth: Why Complex Life is Uncommon in the Universe. Copernicus. <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/2000rewc.book.....W">2000rewc.book.....W</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-387-98701-9" title="Special:BookSources/978-0-387-98701-9"><bdi>978-0-387-98701-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Rare+Earth%3A+Why+Complex+Life+is+Uncommon+in+the+Universe&rft.pub=Copernicus&rft.date=2000&rft_id=info%3Abibcode%2F2000rewc.book.....W&rft.isbn=978-0-387-98701-9&rft.aulast=Ward&rft.aufirst=Peter&rft.au=Brownlee%2C+Donald&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation news cs1"><a rel="nofollow" class="external text" href="http://news.bbc.co.uk/2/hi/uk_news/8642558.stm">"Hawking warns over alien beings"</a>. BBC News. 25 April 2010. Retrieved 2 May 2010.</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=Hawking+warns+over+alien+beings&rft.date=2010-04-25&rft_id=http%3A%2F%2Fnews.bbc.co.uk%2F2%2Fhi%2Fuk_news%2F8642558.stm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-161"><a href="#cite_ref-161">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDiamond2006" class="citation book cs1">Diamond, Jared M. (2006). "Chapter 12". The Third Chimpanzee: The Evolution and Future of the Human Animal. Harper Perennial. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-06-084550-6" title="Special:BookSources/978-0-06-084550-6"><bdi>978-0-06-084550-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Chapter+12&rft.btitle=The+Third+Chimpanzee%3A+The+Evolution+and+Future+of+the+Human+Animal&rft.pub=Harper+Perennial&rft.date=2006&rft.isbn=978-0-06-084550-6&rft.aulast=Diamond&rft.aufirst=Jared+M.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-AP-20150720-162"><a href="#cite_ref-AP-20150720_162-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKatz2015" class="citation news cs1">Katz, Gregory (20 July 2015). <a rel="nofollow" class="external text" href="http://apnews.excite.com/article/20150720/eu--britain-extraterrestrials-e52c157915.html">"Searching for ET: Hawking to look for extraterrestrial life"</a>. Excite!. Associated Press. Retrieved 20 July 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Excite%21&rft.atitle=Searching+for+ET%3A+Hawking+to+look+for+extraterrestrial+life&rft.date=2015-07-20&rft.aulast=Katz&rft.aufirst=Gregory&rft_id=http%3A%2F%2Fapnews.excite.com%2Farticle%2F20150720%2Feu--britain-extraterrestrials-e52c157915.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-NYT-20150213-163"><a href="#cite_ref-NYT-20150213_163-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBorenstein2015" class="citation news cs1">Borenstein, Seth (13 February 2015). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20150214152940/http://www.nytimes.com/aponline/2015/02/13/science/ap-us-sci-calling-the-cosmos.html">"Should We Call the Cosmos Seeking ET? Or Is That Risky?"</a>. <a href="/wiki/The_New_York_Times" title="The New York Times">The New York Times</a>. Associated Press. Archived from <a rel="nofollow" class="external text" href="https://www.nytimes.com/aponline/2015/02/13/science/ap-us-sci-calling-the-cosmos.html">the original</a> on 14 February 2015.</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=Should+We+Call+the+Cosmos+Seeking+ET%3F+Or+Is+That+Risky%3F&rft.date=2015-02-13&rft.aulast=Borenstein&rft.aufirst=Seth&rft_id=https%3A%2F%2Fwww.nytimes.com%2Faponline%2F2015%2F02%2F13%2Fscience%2Fap-us-sci-calling-the-cosmos.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-BBC-20150212-164"><a href="#cite_ref-BBC-20150212_164-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGhosh2015" class="citation news cs1">Ghosh, Pallab (12 February 2015). <a rel="nofollow" class="external text" href="https://www.bbc.com/news/science-environment-31442952">"Scientist: 'Try to contact aliens'"</a>. <a href="/wiki/BBC_News" title="BBC News">BBC News</a>. Retrieved 12 February 2015.</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=Scientist%3A+%27Try+to+contact+aliens%27&rft.date=2015-02-12&rft.aulast=Ghosh&rft.aufirst=Pallab&rft_id=https%3A%2F%2Fwww.bbc.com%2Fnews%2Fscience-environment-31442952&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-UCB-20150213-165"><a href="#cite_ref-UCB-20150213_165-0">^</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://setiathome.berkeley.edu/meti_statement_0.html">"Regarding Messaging To Extraterrestrial Intelligence (METI) / Active Searches For Extraterrestrial Intelligence (Active SETI)"</a>. <a href="/wiki/University_of_California,_Berkeley" title="University of California, Berkeley">University of California, Berkeley</a>. 13 February 2015. Retrieved 14 February 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Regarding+Messaging+To+Extraterrestrial+Intelligence+%28METI%29+%2F+Active+Searches+For+Extraterrestrial+Intelligence+%28Active+SETI%29&rft.pub=University+of+California%2C+Berkeley&rft.date=2015-02-13&rft_id=http%3A%2F%2Fsetiathome.berkeley.edu%2Fmeti_statement_0.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </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="CITEREFMatignon2019" class="citation news cs1">Matignon, Louis (29 May 2019). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20210427042210/https://www.spacelegalissues.com/the-french-anti-ufo-municipal-law-of-1954/">"The French anti-UFO Municipal Law of 1954"</a>. Space Legal Issues. Archived from <a rel="nofollow" class="external text" href="https://www.spacelegalissues.com/the-french-anti-ufo-municipal-law-of-1954/">the original</a> on 27 April 2021. Retrieved 26 March 2021.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Space+Legal+Issues&rft.atitle=The+French+anti-UFO+Municipal+Law+of+1954&rft.date=2019-05-29&rft.aulast=Matignon&rft.aufirst=Louis&rft_id=https%3A%2F%2Fwww.spacelegalissues.com%2Fthe-french-anti-ufo-municipal-law-of-1954%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.un.org/press/en/2010/101014_Othman.doc.htm">"Press Conference by Director of Office for Outer Space Affairs"</a>. UN Press. 14 October 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=UN+Press&rft.atitle=Press+Conference+by+Director+of+Office+for+Outer+Space+Affairs&rft.date=2010-10-14&rft_id=https%3A%2F%2Fwww.un.org%2Fpress%2Fen%2F2010%2F101014_Othman.doc.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFKluger2020" class="citation magazine cs1">Kluger, Jeffrey (2 March 2020). <a rel="nofollow" class="external text" href="https://time.com/5793520/coronavirus-alien-life/">"Coronavirus Could Preview What Will Happen When Alien Life Reaches Earth"</a>. Time.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Time&rft.atitle=Coronavirus+Could+Preview+What+Will+Happen+When+Alien+Life+Reaches+Earth&rft.date=2020-03-02&rft.aulast=Kluger&rft.aufirst=Jeffrey&rft_id=https%3A%2F%2Ftime.com%2F5793520%2Fcoronavirus-alien-life%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFWheeler2017" class="citation web cs1">Wheeler, Michelle (14 July 2017). <a rel="nofollow" class="external text" href="https://particle.scitech.org.au/space/china-next-space-superpower/">"Is China The Next Space Superpower?"</a>. Particle.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Particle&rft.atitle=Is+China+The+Next+Space+Superpower%3F&rft.date=2017-07-14&rft.aulast=Wheeler&rft.aufirst=Michelle&rft_id=https%3A%2F%2Fparticle.scitech.org.au%2Fspace%2Fchina-next-space-superpower%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20190711131334/http://www.xinhuanet.com/english/2019-07/11/c_138218290.htm">"China Focus: Earth's largest radio telescope to search for "new worlds" outside solar system"</a>. Archived from <a rel="nofollow" class="external text" href="http://www.xinhuanet.com/english/2019-07/11/c_138218290.htm">the original</a> on 11 July 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=China+Focus%3A+Earth%27s+largest+radio+telescope+to+search+for+%22new+worlds%22+outside+solar+system&rft_id=http%3A%2F%2Fwww.xinhuanet.com%2Fenglish%2F2019-07%2F11%2Fc_138218290.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://tass.ru/kosmos/9160789">"Рогозин допустил существование жизни на Марсе и других планетах Солнечной системы"</a>. ТАСС.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=%D0%A2%D0%90%D0%A1%D0%A1&rft.atitle=%D0%A0%D0%BE%D0%B3%D0%BE%D0%B7%D0%B8%D0%BD+%D0%B4%D0%BE%D0%BF%D1%83%D1%81%D1%82%D0%B8%D0%BB+%D1%81%D1%83%D1%89%D0%B5%D1%81%D1%82%D0%B2%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D0%B5+%D0%B6%D0%B8%D0%B7%D0%BD%D0%B8+%D0%BD%D0%B0+%D0%9C%D0%B0%D1%80%D1%81%D0%B5+%D0%B8+%D0%B4%D1%80%D1%83%D0%B3%D0%B8%D1%85+%D0%BF%D0%BB%D0%B0%D0%BD%D0%B5%D1%82%D0%B0%D1%85+%D0%A1%D0%BE%D0%BB%D0%BD%D0%B5%D1%87%D0%BD%D0%BE%D0%B9+%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D1%8B&rft_id=https%3A%2F%2Ftass.ru%2Fkosmos%2F9160789&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-newscientist.com-172">^ <a href="#cite_ref-newscientist.com_172-0">a</a> <a href="#cite_ref-newscientist.com_172-1">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.newscientist.com/article/dn11443-france-opens-up-its-ufo-files/">"France opens up its UFO files"</a>. New Scientist. 22 March 2007.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=New+Scientist&rft.atitle=France+opens+up+its+UFO+files&rft.date=2007-03-22&rft_id=https%3A%2F%2Fwww.newscientist.com%2Farticle%2Fdn11443-france-opens-up-its-ufo-files%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" 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="CITEREFBockman2014" class="citation news cs1">Bockman, Chris (4 November 2014). <a rel="nofollow" class="external text" href="https://www.bbc.com/news/magazine-29755919">"Why the French state has a team of UFO hunters"</a>. BBC News.</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=Why+the+French+state+has+a+team+of+UFO+hunters&rft.date=2014-11-04&rft.aulast=Bockman&rft.aufirst=Chris&rft_id=https%3A%2F%2Fwww.bbc.com%2Fnews%2Fmagazine-29755919&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-174"><a href="#cite_ref-174">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJeffay2020" class="citation web cs1">Jeffay, Nathan (10 December 2020). <a rel="nofollow" class="external text" href="https://www.timesofisrael.com/israeli-space-chief-says-aliens-may-well-exist-but-they-havent-met-humans/">"Israeli space chief says aliens may well exist, but they haven't met humans"</a>. <a href="/wiki/The_Times_of_Israel" title="The Times of Israel">The Times of Israel</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Times+of+Israel&rft.atitle=Israeli+space+chief+says+aliens+may+well+exist%2C+but+they+haven%27t+met+humans&rft.date=2020-12-10&rft.aulast=Jeffay&rft.aufirst=Nathan&rft_id=https%3A%2F%2Fwww.timesofisrael.com%2Fisraeli-space-chief-says-aliens-may-well-exist-but-they-havent-met-humans%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> <li id="cite_note-early-175">^ <a href="#cite_ref-early_175-0">a</a> <a href="#cite_ref-early_175-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZaria_Gorvett2023" class="citation web cs1">Zaria Gorvett (22 October 2023). <a rel="nofollow" class="external text" href="https://www.bbc.com/future/article/20231019-the-weird-aliens-of-early-science-fiction">"The weird aliens of early science fiction"</a>. BBC. Retrieved 25 January 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+weird+aliens+of+early+science+fiction&rft.pub=BBC&rft.date=2023-10-22&rft.au=Zaria+Gorvett&rft_id=https%3A%2F%2Fwww.bbc.com%2Ffuture%2Farticle%2F20231019-the-weird-aliens-of-early-science-fiction&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=20" title="Edit section: Further reading">edit</a>]</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="CITEREFAguilera_Mochón2016" class="citation book cs1 cs1-prop-foreign-lang-source">Aguilera Mochón, Juan Antonio (2016). La vida no terrestre [The non-terrestrial life] (in Spanish). RBA. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-84-473-8665-9" title="Special:BookSources/978-84-473-8665-9"><bdi>978-84-473-8665-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=La+vida+no+terrestre&rft.pub=RBA&rft.date=2016&rft.isbn=978-84-473-8665-9&rft.aulast=Aguilera+Moch%C3%B3n&rft.aufirst=Juan+Antonio&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBaird1987" class="citation book cs1">Baird, John C. (1987). <a rel="nofollow" class="external text" href="https://archive.org/details/innerlimitsofout00bair">The Inner Limits of Outer Space: A Psychologist Critiques Our Efforts to Communicate With Extraterrestrial Beings</a>. Hanover: University Press of New England. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-87451-406-3" title="Special:BookSources/978-0-87451-406-3"><bdi>978-0-87451-406-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Inner+Limits+of+Outer+Space%3A+A+Psychologist+Critiques+Our+Efforts+to+Communicate+With+Extraterrestrial+Beings&rft.place=Hanover&rft.pub=University+Press+of+New+England&rft.date=1987&rft.isbn=978-0-87451-406-3&rft.aulast=Baird&rft.aufirst=John+C.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Finnerlimitsofout00bair&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBennett2017" class="citation book cs1">Bennett, Jeffrey (2017). Life in the universe. United States: Pearson. pp. 3–4. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-13-408908-9" title="Special:BookSources/978-0-13-408908-9"><bdi>978-0-13-408908-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Life+in+the+universe&rft.place=United+States&rft.pages=3-4&rft.pub=Pearson&rft.date=2017&rft.isbn=978-0-13-408908-9&rft.aulast=Bennett&rft.aufirst=Jeffrey&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCohenStewart2002" class="citation book cs1"><a href="/wiki/Jack_Cohen_(scientist)" class="mw-redirect" title="Jack Cohen (scientist)">Cohen, Jack</a>; <a href="/wiki/Ian_Stewart_(mathematician)" title="Ian Stewart (mathematician)">Stewart, Ian</a> (2002). <a href="/wiki/Evolving_the_Alien" title="Evolving the Alien">Evolving the Alien: The Science of Extraterrestrial Life</a>. Ebury Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-09-187927-3" title="Special:BookSources/978-0-09-187927-3"><bdi>978-0-09-187927-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Evolving+the+Alien%3A+The+Science+of+Extraterrestrial+Life&rft.pub=Ebury+Press&rft.date=2002&rft.isbn=978-0-09-187927-3&rft.aulast=Cohen&rft.aufirst=Jack&rft.au=Stewart%2C+Ian&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrowe1986" class="citation book cs1">Crowe, Michael J. (1986). The Extraterrestrial Life Debate, 1750–1900. Cambridge. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-26305-4" title="Special:BookSources/978-0-521-26305-4"><bdi>978-0-521-26305-4</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+Extraterrestrial+Life+Debate%2C+1750%E2%80%931900&rft.pub=Cambridge&rft.date=1986&rft.isbn=978-0-521-26305-4&rft.aulast=Crowe&rft.aufirst=Michael+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrowe2008" class="citation book cs1">Crowe, Michael J. (2008). The extraterrestrial life debate Antiquity to 1915: A Source Book. University of Notre Dame Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-268-02368-3" title="Special:BookSources/978-0-268-02368-3"><bdi>978-0-268-02368-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+extraterrestrial+life+debate+Antiquity+to+1915%3A+A+Source+Book&rft.pub=University+of+Notre+Dame+Press&rft.date=2008&rft.isbn=978-0-268-02368-3&rft.aulast=Crowe&rft.aufirst=Michael+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDick1984" class="citation book cs1">Dick, Steven J. (1984). Plurality of Worlds: The Extraterrestrial Life Debate from Democratus to Kant. Cambridge.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Plurality+of+Worlds%3A+The+Extraterrestrial+Life+Debate+from+Democratus+to+Kant&rft.pub=Cambridge&rft.date=1984&rft.aulast=Dick&rft.aufirst=Steven+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDick1996" class="citation book cs1">Dick, Steven J. (1996). The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science. Cambridge. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-34326-8" title="Special:BookSources/978-0-521-34326-8"><bdi>978-0-521-34326-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Biological+Universe%3A+The+Twentieth+Century+Extraterrestrial+Life+Debate+and+the+Limits+of+Science&rft.pub=Cambridge&rft.date=1996&rft.isbn=978-0-521-34326-8&rft.aulast=Dick&rft.aufirst=Steven+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDick2001" class="citation book cs1">Dick, Steven J. (2001). Life on Other Worlds: The 20th Century Extraterrestrial Life Debate. Cambridge. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-521-79912-6" title="Special:BookSources/978-0-521-79912-6"><bdi>978-0-521-79912-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Life+on+Other+Worlds%3A+The+20th+Century+Extraterrestrial+Life+Debate&rft.pub=Cambridge&rft.date=2001&rft.isbn=978-0-521-79912-6&rft.aulast=Dick&rft.aufirst=Steven+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDickStrick2004" class="citation book cs1">Dick, Steven J.; Strick, James E. (2004). <a rel="nofollow" class="external text" href="https://archive.org/details/livinguniversena0000dick">The Living Universe: NASA And the Development of Astrobiology</a>. Rutgers. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8135-3447-3" title="Special:BookSources/978-0-8135-3447-3"><bdi>978-0-8135-3447-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Living+Universe%3A+NASA+And+the+Development+of+Astrobiology&rft.pub=Rutgers&rft.date=2004&rft.isbn=978-0-8135-3447-3&rft.aulast=Dick&rft.aufirst=Steven+J.&rft.au=Strick%2C+James+E.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Flivinguniversena0000dick&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFasan1970" class="citation book cs1">Fasan, Ernst (1970). Relations with alien intelligences – the scientific basis of metalaw. Berlin: Berlin Verlag.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Relations+with+alien+intelligences+%E2%80%93+the+scientific+basis+of+metalaw&rft.place=Berlin&rft.pub=Berlin+Verlag&rft.date=1970&rft.aulast=Fasan&rft.aufirst=Ernst&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGoldsmith1997" class="citation book cs1">Goldsmith, Donald (1997). <a rel="nofollow" class="external text" href="https://archive.org/details/huntforlifeonmar00gold">The Hunt for Life on Mars</a>. New York: A Dutton Book. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-525-94336-5" title="Special:BookSources/978-0-525-94336-5"><bdi>978-0-525-94336-5</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+Hunt+for+Life+on+Mars&rft.place=New+York&rft.pub=A+Dutton+Book&rft.date=1997&rft.isbn=978-0-525-94336-5&rft.aulast=Goldsmith&rft.aufirst=Donald&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fhuntforlifeonmar00gold&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><a href="/wiki/John_Gribbin" title="John Gribbin">Gribbin, John</a>, "Alone in the Milky Way: Why we are probably the only intelligent life in the galaxy", <a href="/wiki/Scientific_American" title="Scientific American">Scientific American</a>, vol. 319, no. 3 (September 2018), pp. 94–99.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrinspoon2003" class="citation book cs1">Grinspoon, David (2003). Lonely Planets: The Natural Philosophy of Alien Life. HarperCollins. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-06-018540-4" title="Special:BookSources/978-0-06-018540-4"><bdi>978-0-06-018540-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Lonely+Planets%3A+The+Natural+Philosophy+of+Alien+Life&rft.pub=HarperCollins&rft.date=2003&rft.isbn=978-0-06-018540-4&rft.aulast=Grinspoon&rft.aufirst=David&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLemnick1998" class="citation book cs1">Lemnick, Michael T. (1998). Other Worlds: The Search for Life in the Universe. New York: A Touchstone Book. <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/1998owsl.book.....L">1998owsl.book.....L</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Other+Worlds%3A+The+Search+for+Life+in+the+Universe&rft.place=New+York&rft.pub=A+Touchstone+Book&rft.date=1998&rft_id=info%3Abibcode%2F1998owsl.book.....L&rft.aulast=Lemnick&rft.aufirst=Michael+T.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichaud2006" class="citation book cs1">Michaud, Michael (2006). <a rel="nofollow" class="external text" href="https://archive.org/details/contactwithalien0000mich">Contact with Alien Civilizations – Our Hopes and Fears about Encountering Extraterrestrials</a>. Berlin: Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-387-28598-6" title="Special:BookSources/978-0-387-28598-6"><bdi>978-0-387-28598-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Contact+with+Alien+Civilizations+%E2%80%93+Our+Hopes+and+Fears+about+Encountering+Extraterrestrials.&rft.place=Berlin&rft.pub=Springer&rft.date=2006&rft.isbn=978-0-387-28598-6&rft.aulast=Michaud&rft.aufirst=Michael&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fcontactwithalien0000mich&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPickover2003" class="citation book cs1"><a href="/wiki/Cliff_Pickover" class="mw-redirect" title="Cliff Pickover">Pickover, Cliff</a> (2003). The Science of Aliens. New York: Basic Books. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-465-07315-3" title="Special:BookSources/978-0-465-07315-3"><bdi>978-0-465-07315-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Science+of+Aliens&rft.place=New+York&rft.pub=Basic+Books&rft.date=2003&rft.isbn=978-0-465-07315-3&rft.aulast=Pickover&rft.aufirst=Cliff&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRoth2005" class="citation book cs1">Roth, Christopher F. (2005). Debbora Battaglia (ed.). Ufology as Anthropology: Race, Extraterrestrials, and the Occult. Durham, NC: Duke University Press.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Ufology+as+Anthropology%3A+Race%2C+Extraterrestrials%2C+and+the+Occult&rft.place=Durham%2C+NC&rft.pub=Duke+University+Press&rft.date=2005&rft.aulast=Roth&rft.aufirst=Christopher+F.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"> <code class="cs1-code">{{<a href="/wiki/Template:Cite_book" title="Template:Cite book">cite book</a>}}</code>: <code class="cs1-code">|work=</code> ignored (<a href="/wiki/Help:CS1_errors#periodical_ignored" title="Help:CS1 errors">help</a>)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSaganShklovskii1966" class="citation book cs1"><a href="/wiki/Carl_Sagan" title="Carl Sagan">Sagan, Carl</a>; <a href="/wiki/I.S._Shklovskii" class="mw-redirect" title="I.S. Shklovskii">Shklovskii, I. S.</a> (1966). Intelligent Life in the Universe. Random House.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Intelligent+Life+in+the+Universe&rft.pub=Random+House&rft.date=1966&rft.aulast=Sagan&rft.aufirst=Carl&rft.au=Shklovskii%2C+I.+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSagan1973" class="citation book cs1">Sagan, Carl (1973). <a href="/wiki/Communication_with_Extraterrestrial_Intelligence" class="mw-redirect" title="Communication with Extraterrestrial Intelligence">Communication with Extraterrestrial Intelligence</a>. MIT Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-262-19106-7" title="Special:BookSources/978-0-262-19106-7"><bdi>978-0-262-19106-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Communication+with+Extraterrestrial+Intelligence&rft.pub=MIT+Press&rft.date=1973&rft.isbn=978-0-262-19106-7&rft.aulast=Sagan&rft.aufirst=Carl&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWard2005" class="citation book cs1">Ward, Peter D. (2005). <a rel="nofollow" class="external text" href="https://archive.org/details/lifeaswedonotkno00ward">Life as we do not know it-the NASA search for (and synthesis of) alien life</a>. New York: Viking. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-670-03458-1" title="Special:BookSources/978-0-670-03458-1"><bdi>978-0-670-03458-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Life+as+we+do+not+know+it-the+NASA+search+for+%28and+synthesis+of%29+alien+life&rft.place=New+York&rft.pub=Viking&rft.date=2005&rft.isbn=978-0-670-03458-1&rft.aulast=Ward&rft.aufirst=Peter+D.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Flifeaswedonotkno00ward&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTumminia2007" class="citation book cs1">Tumminia, Diana G. (2007). <a rel="nofollow" class="external text" href="https://archive.org/details/alienworldssocia0000unse">Alien Worlds – Social and Religious Dimensions of Extraterrestrial Contact</a>. Syracuse: Syracuse University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8156-0858-5" title="Special:BookSources/978-0-8156-0858-5"><bdi>978-0-8156-0858-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Alien+Worlds+%E2%80%93+Social+and+Religious+Dimensions+of+Extraterrestrial+Contact&rft.place=Syracuse&rft.pub=Syracuse+University+Press&rft.date=2007&rft.isbn=978-0-8156-0858-5&rft.aulast=Tumminia&rft.aufirst=Diana+G.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Falienworldssocia0000unse&rfr_id=info%3Asid%2Fen.wikipedia.org%3AExtraterrestrial+life" class="Z3988"></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2>[<a href="/w/index.php?title=Extraterrestrial_life&action=edit&section=21" title="Edit section: External links">edit</a>]</div> <style 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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="Extraterrestrial_life" 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" 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:Extraterrestrial_life" title="Template:Extraterrestrial life"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Extraterrestrial_life" title="Template talk:Extraterrestrial life"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Extraterrestrial_life" title="Special:EditPage/Template:Extraterrestrial life"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Extraterrestrial_life" style="font-size:114%;margin:0 4em"><a class="mw-selflink selflink">Extraterrestrial life</a></div></th></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Events and objects</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/Shergotty_meteorite" title="Shergotty meteorite">Shergotty meteorite</a> (1865)</li> <li><a href="/wiki/Nakhla_meteorite" title="Nakhla meteorite">Nakhla meteorite</a> (1911)</li> <li><a href="/wiki/Murchison_meteorite" title="Murchison meteorite">Murchison meteorite</a> (1969)</li> <li><a href="/wiki/Viking_lander_biological_experiments" title="Viking lander biological experiments">Viking lander biological experiments</a> (1976)</li> <li><a href="/wiki/Allan_Hills_77005" title="Allan Hills 77005">Allan Hills 77005</a> (1977)</li> <li><a href="/wiki/Allan_Hills_84001" title="Allan Hills 84001">Allan Hills 84001</a> (1984)</li> <li><a href="/wiki/Yamato_000593" title="Yamato 000593">Yamato 000593</a> (2000)</li> <li><a href="/wiki/CI1_fossils" title="CI1 fossils">CI1 fossils</a> (2011)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Signals of interest</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%;text-align: center;">Misidentified</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/PSR_B1919%2B21" title="PSR B1919+21">CP 1919</a> (misidentified pulsar)</li> <li><a href="/wiki/CTA-102" title="CTA-102">CTA-102</a> (misidentified quasar)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">Stars</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/Tabby%27s_Star" title="Tabby's Star">KIC 8462852</a> (unusual light fluctuations)</li> <li><a href="/wiki/EPIC_204278916" title="EPIC 204278916">EPIC 204278916</a> (unusual light fluctuations)</li> <li><a href="/wiki/VVV-WIT-07" title="VVV-WIT-07">VVV-WIT-07</a> (unusual light fluctuations)</li> <li><a href="/wiki/HD_164595" title="HD 164595">HD 164595 signal</a> (unknown origin)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">Other</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/SHGb02%2B14a" title="SHGb02+14a">SHGb02+14a</a> (radio source)</li> <li><a href="/wiki/Wow!_signal" title="Wow! signal">Wow! signal</a> (inconclusive)</li> <li><a href="/wiki/Fast_radio_burst" title="Fast radio burst">Fast radio burst</a> (unknown origin)</li> <li><a href="/wiki/BLC1" title="BLC1">BLC1</a> (radio signal)</li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Life in the Universe</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/Earliest_known_life_forms" title="Earliest known life forms">Earliest known life forms</a></li> <li><a href="/wiki/Planetary_habitability_in_the_Solar_System" title="Planetary habitability in the Solar System">Planetary habitability in the Solar System</a></li> <li><a href="/wiki/Life_on_Venus" title="Life on Venus">Life on Venus</a></li> <li><a href="/wiki/Life_on_Mars" title="Life on Mars">Life on Mars</a></li> <li><a href="/wiki/Life_on_Titan" title="Life on Titan">Life on Titan</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Planetary_habitability" title="Planetary habitability">Planetary habitability</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/Catalog_of_Nearby_Habitable_Systems" title="Catalog of Nearby Habitable Systems">Catalog of Nearby Habitable Systems</a></li> <li><a href="/wiki/Circumstellar_habitable_zone" class="mw-redirect" title="Circumstellar habitable zone">Circumstellar habitable zone</a></li> <li><a href="/wiki/Earth_analog" title="Earth analog">Earth analog</a></li> <li><a href="/wiki/Extraterrestrial_liquid_water" title="Extraterrestrial liquid water">Extraterrestrial liquid water</a></li> <li><a href="/wiki/Galactic_habitable_zone" title="Galactic habitable zone">Galactic habitable zone</a></li> <li><a href="/wiki/Habitability_of_binary_star_systems" title="Habitability of binary star systems">Habitability of binary star systems</a></li> <li><a href="/wiki/Habitability_of_natural_satellites" title="Habitability of natural satellites">Habitability of natural satellites</a></li> <li><a href="/wiki/Habitability_of_neutron_star_systems" title="Habitability of neutron star systems">Habitability of neutron star systems</a></li> <li><a href="/wiki/Habitability_of_red_dwarf_systems" title="Habitability of red dwarf systems">Habitability of red dwarf systems</a></li> <li><a href="/wiki/Habitability_of_K-type_main-sequence_star_systems" title="Habitability of K-type main-sequence star systems">Habitability of K-type main-sequence star systems</a></li> <li><a href="/wiki/Habitability_of_yellow_dwarf_systems" title="Habitability of yellow dwarf systems">Habitability of yellow dwarf systems</a></li> <li><a href="/wiki/Habitability_of_F-type_main-sequence_star_systems" title="Habitability of F-type main-sequence star systems">Habitability of F-type main-sequence star systems</a></li> <li><a href="/wiki/List_of_potentially_habitable_exoplanets" title="List of potentially habitable exoplanets">List of potentially habitable exoplanets</a></li> <li><a href="/wiki/Planetary_habitability" title="Planetary habitability">Planetary habitability</a></li> <li><a href="/wiki/Superhabitable_planet" class="mw-redirect" title="Superhabitable planet">Superhabitable planet</a></li> <li><a href="/wiki/Tholin" title="Tholin">Tholin</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Astrobiology#Missions" title="Astrobiology">Space missions</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/Beagle_2" title="Beagle 2">Beagle 2</a></li> <li><a href="/wiki/Biological_Oxidant_and_Life_Detection" title="Biological Oxidant and Life Detection">Biological Oxidant and Life Detection</a></li> <li><a href="/wiki/BioSentinel" title="BioSentinel">BioSentinel</a></li> <li><a href="/wiki/Curiosity_(rover)" title="Curiosity (rover)">Curiosity rover</a></li> <li><a href="/wiki/Darwin_(spacecraft)" title="Darwin (spacecraft)">Darwin</a></li> <li><a href="/wiki/Dragonfly_(Titan_space_probe)" title="Dragonfly (Titan space probe)">Dragonfly</a></li> <li><a href="/wiki/Enceladus_Explorer" title="Enceladus Explorer">Enceladus Explorer</a></li> <li><a href="/wiki/Enceladus_Life_Finder" title="Enceladus Life Finder">Enceladus Life Finder</a></li> <li><a href="/wiki/Europa_Clipper" title="Europa Clipper">Europa Clipper</a></li> <li><a href="/wiki/ExoMars" title="ExoMars">ExoMars</a> <ul><li><a href="/wiki/Rosalind_Franklin_(rover)" title="Rosalind Franklin (rover)">Rosalind Franklin rover</a></li></ul></li> <li><a href="/wiki/ExoLance" title="ExoLance">ExoLance</a></li> <li><a href="/wiki/EXPOSE" title="EXPOSE">EXPOSE</a></li> <li><a href="/wiki/Foton-M" class="mw-redirect" title="Foton-M">Foton-M3</a></li> <li><a href="/wiki/Icebreaker_Life" title="Icebreaker Life">Icebreaker Life</a></li> <li><a href="/wiki/Journey_to_Enceladus_and_Titan" title="Journey to Enceladus and Titan">Journey to Enceladus and Titan</a></li> <li><a href="/wiki/Laplace-P" title="Laplace-P">Laplace-P</a></li> <li><a href="/wiki/Life_Investigation_For_Enceladus" title="Life Investigation For Enceladus">Life Investigation For Enceladus</a></li> <li><a href="/wiki/Living_Interplanetary_Flight_Experiment" title="Living Interplanetary Flight Experiment">Living Interplanetary Flight Experiment</a></li> <li><a href="/wiki/Mars_Geyser_Hopper" title="Mars Geyser Hopper">Mars Geyser Hopper</a></li> <li><a href="/wiki/Mars_sample-return_mission" title="Mars sample-return mission">Mars sample-return mission</a></li> <li><a href="/wiki/Mars_2020" title="Mars 2020">Mars 2020</a></li> <li><a href="/wiki/Northern_Light_(spacecraft)" title="Northern Light (spacecraft)">Northern Light</a></li> <li><a href="/wiki/Opportunity_(rover)" title="Opportunity (rover)">Opportunity rover</a></li> <li><a href="/wiki/Perseverance_(rover)" title="Perseverance (rover)">Perseverance rover</a></li> <li><a href="/wiki/SpaceX_Red_Dragon" title="SpaceX Red Dragon">SpaceX Red Dragon</a></li> <li><a href="/wiki/Spirit_(rover)" title="Spirit (rover)">Spirit rover</a></li> <li><a href="/wiki/Tanpopo_mission" title="Tanpopo mission">Tanpopo</a></li> <li><a href="/wiki/Titan_Mare_Explorer" title="Titan Mare Explorer">Titan Mare Explorer</a></li> <li><a href="/wiki/Venus_In_Situ_Explorer" title="Venus In Situ Explorer">Venus In Situ Explorer</a></li> <li><a href="/wiki/Viking_1" title="Viking 1">Viking 1</a></li> <li><a href="/wiki/Viking_2" title="Viking 2">Viking 2</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Interstellar_communication" title="Interstellar communication">Interstellar communication</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/Active_SETI" title="Active SETI">Active SETI</a></li> <li><a href="/wiki/Allen_Telescope_Array" title="Allen Telescope Array">Allen Telescope Array</a></li> <li><a href="/wiki/Arecibo_message" title="Arecibo message">Arecibo message</a></li> <li><a href="/wiki/Arecibo_Observatory" title="Arecibo Observatory">Arecibo Observatory</a></li> <li><a href="/wiki/Berkeley_SETI_Research_Center" title="Berkeley SETI Research Center">Berkeley SETI Research Center</a></li> <li><a href="/wiki/Bracewell_probe" title="Bracewell probe">Bracewell probe</a></li> <li><a href="/wiki/Breakthrough_Initiatives" title="Breakthrough Initiatives">Breakthrough Initiatives</a> <ul><li><a href="/wiki/Breakthrough_Listen" title="Breakthrough Listen">Breakthrough Listen</a></li> <li><a href="/wiki/Breakthrough_Message" class="mw-redirect" title="Breakthrough Message">Breakthrough Message</a></li></ul></li> <li><a href="/wiki/Communication_with_extraterrestrial_intelligence" title="Communication with extraterrestrial intelligence">Communication with extraterrestrial intelligence</a></li> <li><a href="/wiki/Gauss%27s_Pythagorean_right_triangle_proposal" title="Gauss's Pythagorean right triangle proposal">Gauss's Pythagorean right triangle proposal</a></li> <li><a href="/wiki/Astrolinguistics" title="Astrolinguistics">Astrolinguistics</a></li> <li><a href="/wiki/Lincos_language" title="Lincos language">Lincos language</a></li> <li><a href="/wiki/NIROSETI" title="NIROSETI">NIROSETI</a></li> <li><a href="/wiki/Pioneer_plaque" title="Pioneer plaque">Pioneer plaque</a></li> <li><a href="/wiki/Project_Cyclops" title="Project Cyclops">Project Cyclops</a></li> <li><a href="/wiki/Project_Ozma" title="Project Ozma">Project Ozma</a></li> <li><a href="/wiki/Project_Phoenix_(SETI)" title="Project Phoenix (SETI)">Project Phoenix</a></li> <li><a href="/wiki/SERENDIP" title="SERENDIP">SERENDIP</a></li> <li><a href="/wiki/Search_for_extraterrestrial_intelligence" title="Search for extraterrestrial intelligence">Search for extraterrestrial intelligence</a></li> <li><a href="/wiki/SETI@home" title="SETI@home">SETI@home</a></li> <li><a href="/wiki/SetiQuest" title="SetiQuest">setiQuest</a></li> <li><a href="/wiki/Voyager_Golden_Record" title="Voyager Golden Record">Voyager Golden Record</a></li> <li><a href="/wiki/Water_hole_(radio)" title="Water hole (radio)">Water hole</a></li> <li><a href="/wiki/Alien_language" title="Alien language">Xenolinguistics</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/List_of_alleged_extraterrestrial_beings" title="List of alleged extraterrestrial beings">Types of alleged extraterrestrial beings</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/Energy_being" title="Energy being">Energy beings</a></li> <li><a href="/wiki/Grey_alien" title="Grey alien">Grey aliens</a></li> <li><a href="/wiki/Insectoids_in_science_fiction" class="mw-redirect" title="Insectoids in science fiction">Insectoids</a></li> <li><a href="/wiki/Little_green_men" title="Little green men">Little green men</a></li> <li><a href="/wiki/Nordic_aliens" title="Nordic aliens">Nordic aliens</a></li> <li><a href="/wiki/Reptilian_humanoid" title="Reptilian humanoid">Reptilian humanoids</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Hypotheses</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/Cosmic_pluralism" title="Cosmic pluralism">Cosmic pluralism</a></li> <li><a href="/wiki/Directed_panspermia" title="Directed panspermia">Directed panspermia</a></li> <li><a href="/wiki/Drake_equation" title="Drake equation">Drake equation</a></li> <li><a href="/wiki/Extraterrestrial_hypothesis" class="mw-redirect" title="Extraterrestrial hypothesis">Extraterrestrial hypothesis</a></li> <li><a href="/wiki/Fermi_paradox" title="Fermi paradox">Fermi paradox</a></li> <li><a href="/wiki/Hypothetical_types_of_biochemistry" title="Hypothetical types of biochemistry">Hypothetical types of biochemistry</a></li> <li><a href="/wiki/Interplanetary_contamination" title="Interplanetary contamination">Interplanetary contamination</a></li> <li><a href="/wiki/Kardashev_scale" title="Kardashev scale">Kardashev scale</a></li> <li><a href="/wiki/Mediocrity_principle" title="Mediocrity principle">Mediocrity principle</a></li> <li><a href="/wiki/Panspermia" title="Panspermia">Panspermia</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Fermi_paradox" title="Fermi paradox">Fermi paradox</a> solutions</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/Aestivation_hypothesis" title="Aestivation hypothesis">Aestivation hypothesis</a></li> <li><a href="/wiki/Berserker_hypothesis" title="Berserker hypothesis">Berserker hypothesis</a></li> <li><a href="/wiki/Dark_forest_hypothesis" title="Dark forest hypothesis">Dark forest hypothesis</a></li> <li><a href="/wiki/Firstborn_hypothesis" title="Firstborn hypothesis">Firstborn hypothesis</a></li> <li><a href="/wiki/Great_Filter" title="Great Filter">Great Filter</a></li> <li><a href="/wiki/Hart%E2%80%93Tipler_conjecture" title="Hart–Tipler conjecture">Hart–Tipler conjecture</a></li> <li><a href="/wiki/Neocatastrophism" title="Neocatastrophism">Neocatastrophism</a></li> <li><a href="/wiki/Planetarium_hypothesis" title="Planetarium hypothesis">Planetarium hypothesis</a></li> <li><a href="/wiki/Rare_Earth_hypothesis" title="Rare Earth hypothesis">Rare Earth hypothesis</a></li> <li><a href="/wiki/Zoo_hypothesis" title="Zoo hypothesis">Zoo hypothesis</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Outline_of_extraterrestrial_life" title="Outline of extraterrestrial life">Related topics</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/Ancient_astronauts" title="Ancient astronauts">Ancient astronauts</a></li> <li><a href="/wiki/Astrobiology" title="Astrobiology">Astrobiology</a></li> <li><a href="/wiki/Astroecology" title="Astroecology">Astroecology</a></li> <li><a href="/wiki/Biosignature" title="Biosignature">Biosignature</a></li> <li><a href="/wiki/Brookings_Report" title="Brookings Report">Brookings Report</a></li> <li><a href="/wiki/Exotheology" title="Exotheology">Exotheology</a></li> <li><a href="/wiki/Extraterrestrials_in_fiction" title="Extraterrestrials in fiction">Extraterrestrials in fiction</a></li> <li><a href="/wiki/Extremophile" title="Extremophile">Extremophile</a></li> <li><a href="/wiki/Hemolithin" title="Hemolithin">Hemolithin</a></li> <li><a href="/wiki/History_of_the_extraterrestrial_life_debate" title="History of the extraterrestrial life debate">History of the extraterrestrial life debate</a></li> <li><a href="/wiki/MERMOZ" title="MERMOZ">MERMOZ</a></li> <li><a href="/wiki/Nexus_for_Exoplanet_System_Science" title="Nexus for Exoplanet System Science">Nexus for Exoplanet System Science</a></li> <li><a href="/wiki/Noosphere" title="Noosphere">Noogenesis</a></li> <li><a href="/wiki/Planetary_protection" title="Planetary protection">Planetary protection</a></li> <li><a href="/wiki/Potential_cultural_impact_of_extraterrestrial_contact" title="Potential cultural impact of extraterrestrial contact">Potential cultural impact of extraterrestrial contact</a></li> <li><a href="/wiki/Post-detection_policy" title="Post-detection policy">Post-detection policy</a></li> <li><a href="/wiki/San_Marino_Scale" title="San Marino Scale">San Marino Scale</a></li> <li><a href="/wiki/Technosignature" title="Technosignature">Technosignature</a></li> <li><a href="/wiki/UFO_religion" title="UFO religion">UFO religion</a></li> <li><a href="/wiki/Xenoarchaeology" title="Xenoarchaeology">Xenoarchaeology</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="Astrobiology" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse 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:Astrobiology" title="Template:Astrobiology"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Astrobiology" title="Template talk:Astrobiology"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Astrobiology" title="Special:EditPage/Template:Astrobiology"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Astrobiology" style="font-size:114%;margin:0 4em"><a href="/wiki/Astrobiology" title="Astrobiology">Astrobiology</a></div></th></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Disciplines</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/Astrochemistry" title="Astrochemistry">Astrochemistry</a></li> <li><a href="/wiki/Astrophysics" title="Astrophysics">Astrophysics</a></li> <li><a href="/wiki/Atmospheric_sciences" class="mw-redirect" title="Atmospheric sciences">Atmospheric sciences</a></li> <li><a href="/wiki/Biochemistry" title="Biochemistry">Biochemistry</a></li> <li><a href="/wiki/Evolutionary_biology" title="Evolutionary biology">Evolutionary biology</a></li> <li><a href="/wiki/Exoplanetology" class="mw-redirect" title="Exoplanetology">Exoplanetology</a></li> <li><a href="/wiki/Geomicrobiology" title="Geomicrobiology">Geomicrobiology</a></li> <li><a href="/wiki/Microbiology" title="Microbiology">Microbiology</a></li> <li><a href="/wiki/Paleontology" title="Paleontology">Paleontology</a></li> <li><a href="/wiki/Planetary_oceanography" title="Planetary oceanography">Planetary oceanography</a></li> <li><a href="/wiki/Planetary_science" title="Planetary science">Planetary science</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Main topics</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/Abiogenesis" title="Abiogenesis">Abiogenesis</a></li> <li><a href="/wiki/Allan_Hills_84001" title="Allan Hills 84001">Allan Hills 84001</a></li> <li><a href="/wiki/Biomolecule" title="Biomolecule">Biomolecule</a></li> <li><a href="/wiki/Biosignature" title="Biosignature">Biosignature</a></li> <li><a href="/wiki/Drake_equation" title="Drake equation">Drake equation</a></li> <li><a href="/wiki/Earliest_known_life_forms" title="Earliest known life forms">Earliest known life forms</a></li> <li><a href="/wiki/Earth_analog" title="Earth analog">Earth analog</a></li> <li><a class="mw-selflink selflink">Extraterrestrial life</a></li> <li><a href="/wiki/Extraterrestrial_sample_curation" title="Extraterrestrial sample curation">Extraterrestrial sample curation</a></li> <li><a href="/wiki/Extremophile" title="Extremophile">Extremophiles</a></li> <li><a href="/wiki/Hypothetical_types_of_biochemistry" title="Hypothetical types of biochemistry">Hypothetical types of biochemistry</a></li> <li><a href="/wiki/List_of_microorganisms_tested_in_outer_space" title="List of microorganisms tested in outer space">List of microorganisms tested in outer space</a></li> <li><a href="/wiki/Ocean_planet" class="mw-redirect" title="Ocean planet">Ocean planet</a></li> <li><a href="/wiki/Panspermia" title="Panspermia">Panspermia</a></li> <li><a href="/wiki/Planetary_protection" title="Planetary protection">Planetary protection</a></li> <li><a href="/wiki/Search_for_extraterrestrial_intelligence" title="Search for extraterrestrial intelligence">Search for extraterrestrial intelligence (SETI)</a></li> <li><a href="/wiki/Yamato_000593" title="Yamato 000593">Yamato meteorite</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%"><a href="/wiki/Planetary_habitability" title="Planetary habitability">Planetary habitability</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/Circumstellar_habitable_zone" class="mw-redirect" title="Circumstellar habitable zone">Circumstellar habitable zone</a></li> <li><a href="/wiki/Earth_analog" title="Earth analog">Earth analog</a></li> <li><a href="/wiki/Extraterrestrial_liquid_water" title="Extraterrestrial liquid water">Extraterrestrial liquid water</a></li> <li><a href="/wiki/Galactic_habitable_zone" title="Galactic habitable zone">Galactic habitable zone</a></li> <li><a href="/wiki/Habitability_of_binary_star_systems" title="Habitability of binary star systems">Habitability of binary star systems</a></li> <li><a href="/wiki/Habitability_of_natural_satellites" title="Habitability of natural satellites">Habitability of natural satellites</a></li> <li><a href="/wiki/Habitability_of_neutron_star_systems" title="Habitability of neutron star systems">Habitability of neutron star systems</a></li> <li><a href="/wiki/Habitability_of_red_dwarf_systems" title="Habitability of red dwarf systems">Habitability of red dwarf systems</a></li> <li><a href="/wiki/Habitability_of_K-type_main-sequence_star_systems" title="Habitability of K-type main-sequence star systems">Habitability of K-type main-sequence star systems</a></li> <li><a href="/wiki/Habitability_of_yellow_dwarf_systems" title="Habitability of yellow dwarf systems">Habitability of yellow dwarf systems</a></li> <li><a href="/wiki/Habitability_of_F-type_main-sequence_star_systems" title="Habitability of F-type main-sequence star systems">Habitability of F-type main-sequence star systems</a></li> <li><a href="/wiki/Habitable_zone_for_complex_life" title="Habitable zone for complex life">Habitable zone for complex life</a></li> <li><a href="/wiki/List_of_potentially_habitable_exoplanets" title="List of potentially habitable exoplanets">List of potentially habitable exoplanets</a></li> <li><a href="/wiki/Tholin" title="Tholin">Tholin</a></li> <li><a href="/wiki/Superhabitable_planet" class="mw-redirect" title="Superhabitable planet">Superhabitable planet</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Space missions</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%;text-align: center;">Earth orbit</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/Space_Flyer_Unit#Experimentation_data" title="Space Flyer Unit">BIO</a></li> <li><a href="/wiki/Apollo_17#Biological_cosmic_ray_experiment" title="Apollo 17">BIOCORE</a></li> <li><a href="/wiki/Biolab" title="Biolab">Biolab</a></li> <li><a href="/wiki/Bion_(satellite)" title="Bion (satellite)">Bion</a></li> <li><a href="/wiki/BIOPAN" title="BIOPAN">BIOPAN</a></li> <li><a href="/wiki/Biosatellite_program" title="Biosatellite program">Biosatellite program</a></li> <li><a href="/wiki/Exposing_Microorganisms_in_the_Stratosphere" title="Exposing Microorganisms in the Stratosphere">E-MIST</a></li> <li><a href="/wiki/Exobiology_Radiation_Assembly" title="Exobiology Radiation Assembly">ERA</a></li> <li><a href="/wiki/EuCROPIS" title="EuCROPIS">Eu:CROPIS</a></li> <li><a href="/wiki/Long_Duration_Exposure_Facility#EXOSTACK" title="Long Duration Exposure Facility">EXOSTACK</a></li> <li><a href="/wiki/EXPOSE" title="EXPOSE">EXPOSE</a></li> <li><a href="/wiki/Chang%27e_4#Lunar_lander" title="Chang'e 4">Lunar Micro Ecosystem</a></li> <li><a href="/wiki/O/OREOS" title="O/OREOS">O/OREOS</a></li> <li><a href="/wiki/OREOcube" title="OREOcube">OREOcube</a></li> <li><a href="/wiki/Tanpopo_(mission)" class="mw-redirect" title="Tanpopo (mission)">Tanpopo</a></li> <li><a href="/wiki/Vegetable_Production_System" title="Vegetable Production System">VEGGIE</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">Mars</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/Beagle_2" title="Beagle 2">Beagle 2</a></li> <li><a href="/wiki/Fobos-Grunt" title="Fobos-Grunt">Fobos-Grunt</a></li> <li><a href="/wiki/Mars_Science_Laboratory" title="Mars Science Laboratory">Mars Science Laboratory</a> <ul><li><a href="/wiki/Curiosity_(rover)" title="Curiosity (rover)">Curiosity rover</a></li></ul></li> <li><a href="/wiki/Mars_2020" title="Mars 2020">Mars 2020</a> <ul><li><a href="/wiki/Perseverance_(rover)" title="Perseverance (rover)">Perseverance rover</a></li></ul></li> <li><a href="/wiki/Phoenix_(spacecraft)" title="Phoenix (spacecraft)">Phoenix</a></li> <li><a href="/wiki/Tianwen-1" title="Tianwen-1">Tianwen-1</a> <ul><li><a href="/wiki/Zhurong_(rover)" title="Zhurong (rover)">Zhurong rover</a></li></ul></li> <li><a href="/wiki/Trace_Gas_Orbiter" title="Trace Gas Orbiter">Trace Gas Orbiter</a></li> <li><a href="/wiki/Viking_lander_biological_experiments" title="Viking lander biological experiments">Viking</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">Comets and asteroids</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/Hayabusa2" title="Hayabusa2">Hayabusa2</a></li> <li><a href="/wiki/OSIRIS-REx" title="OSIRIS-REx">OSIRIS-REx</a></li> <li><a href="/wiki/Rosetta_(spacecraft)" title="Rosetta (spacecraft)">Rosetta</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">Heliocentric</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/BioSentinel" title="BioSentinel">BioSentinel</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">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/Dragonfly_(Titan_space_probe)" title="Dragonfly (Titan space probe)">Dragonfly</a></li> <li><a href="/wiki/Europa_Clipper" title="Europa Clipper">Europa Clipper</a></li> <li><a href="/wiki/ExoMars" title="ExoMars">ExoMars</a> <ul><li><a href="/wiki/Rosalind_Franklin_(rover)" title="Rosalind Franklin (rover)">Rosalind Franklin rover</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">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/Breakthrough_Enceladus_mission" title="Breakthrough Enceladus mission">Breakthrough Enceladus</a></li> <li><a href="/wiki/BRUIE" title="BRUIE">BRUIE</a></li> <li><a href="/wiki/CAESAR_(spacecraft)" title="CAESAR (spacecraft)">CAESAR</a></li> <li><a href="/wiki/Enceladus_Explorer" title="Enceladus Explorer">Enceladus Explorer</a></li> <li><a href="/wiki/Enceladus_Life_Finder" title="Enceladus Life Finder">Enceladus Life Finder‎</a></li> <li><a href="/wiki/Enceladus_Life_Signatures_and_Habitability" title="Enceladus Life Signatures and Habitability">Enceladus Life Signatures and Habitability</a></li> <li><a href="/wiki/Enceladus_Orbilander" title="Enceladus Orbilander">Enceladus Orbilander</a></li> <li><a href="/wiki/Europa_Lander_(NASA)" class="mw-redirect" title="Europa Lander (NASA)">Europa Lander</a></li> <li><a href="/wiki/ExoLance" title="ExoLance">ExoLance</a></li> <li><a href="/wiki/Explorer_of_Enceladus_and_Titan" title="Explorer of Enceladus and Titan">Explorer of Enceladus and Titan</a></li> <li><a href="/wiki/Icebreaker_Life" title="Icebreaker Life">Icebreaker Life</a></li> <li><a href="/wiki/Journey_to_Enceladus_and_Titan" title="Journey to Enceladus and Titan">Journey to Enceladus and Titan</a></li> <li><a href="/wiki/Laplace-P" title="Laplace-P">Laplace-P</a></li> <li><a href="/wiki/Life_Investigation_For_Enceladus" title="Life Investigation For Enceladus">Life Investigation For Enceladus</a></li> <li><a href="/wiki/Mars_sample_return_mission" class="mw-redirect" title="Mars sample return mission">Mars sample return mission</a></li> <li><a href="/wiki/Oceanus_(Titan_orbiter)" title="Oceanus (Titan orbiter)">Oceanus</a></li> <li><a href="/wiki/THEO" title="THEO">THEO</a></li> <li><a href="/wiki/Trident_(spacecraft)" title="Trident (spacecraft)">Trident</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align: center;">Cancelled and undeveloped</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/Astrobiology_Field_Laboratory" title="Astrobiology Field Laboratory">Astrobiology Field Laboratory</a></li> <li><a href="/wiki/Beagle_3" title="Beagle 3">Beagle 3</a></li> <li><a href="/wiki/Biological_Oxidant_and_Life_Detection" title="Biological Oxidant and Life Detection">Biological Oxidant and Life Detection</a></li> <li><a href="/wiki/Kazachok" title="Kazachok">Kazachok</a></li> <li><a href="/wiki/Living_Interplanetary_Flight_Experiment" title="Living Interplanetary Flight Experiment">Living Interplanetary Flight Experiment</a></li> <li><a href="/wiki/Mars_Astrobiology_Explorer-Cacher" title="Mars Astrobiology Explorer-Cacher">Mars Astrobiology Explorer-Cacher</a></li> <li><a href="/wiki/MELOS" title="MELOS">MELOS</a></li> <li><a href="/wiki/Northern_Light_(spacecraft)" title="Northern Light (spacecraft)">Northern Light</a></li> <li><a href="/wiki/SpaceX_Red_Dragon" title="SpaceX Red Dragon">Red Dragon</a></li> <li><a href="/wiki/Terrestrial_Planet_Finder" title="Terrestrial Planet Finder">Terrestrial Planet Finder</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%">Institutions and programs</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/Astrobiology_Society_of_Britain" title="Astrobiology Society of Britain">Astrobiology Society of Britain</a></li> <li><a href="/wiki/Astrobiology_Science_and_Technology_for_Exploring_Planets" title="Astrobiology Science and Technology for Exploring Planets">Astrobiology Science and Technology for Exploring Planets</a></li> <li><a href="/wiki/Breakthrough_Initiatives" title="Breakthrough Initiatives">Breakthrough Initiatives</a> <ul><li><a href="/wiki/Breakthrough_Listen" title="Breakthrough Listen">Breakthrough Listen</a></li> <li><a href="/wiki/Breakthrough_Message" class="mw-redirect" title="Breakthrough Message">Breakthrough Message</a></li> <li><a href="/wiki/Breakthrough_Starshot" title="Breakthrough Starshot">Breakthrough Starshot</a></li></ul></li> <li><a href="/wiki/Carl_Sagan_Institute" title="Carl Sagan Institute">Carl Sagan Institute</a></li> <li><a href="/wiki/Center_for_Life_Detection_Science" class="mw-redirect" title="Center for Life Detection Science">Center for Life Detection Science</a></li> <li><a href="/wiki/European_Astrobiology_Network_Association" title="European Astrobiology Network Association">European Astrobiology Network Association</a></li> <li><a href="/wiki/MERMOZ" title="MERMOZ">MERMOZ</a></li> <li><a href="/wiki/NASA_Astrobiology_Institute" title="NASA Astrobiology Institute">NASA Astrobiology Institute</a></li> <li><a href="/wiki/Nexus_for_Exoplanet_System_Science" title="Nexus for Exoplanet System Science">Nexus for Exoplanet System Science</a></li> <li><a href="/wiki/Ocean_Worlds_Exploration_Program" title="Ocean Worlds Exploration Program">Ocean Worlds Exploration Program</a></li> <li><a href="/wiki/Spanish_Astrobiology_Center" title="Spanish Astrobiology Center">Spanish Astrobiology Center‎</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2" style="text-align: center;"><div> <ul><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:Astrobiology" title="Category:Astrobiology">Category</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/18px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/24px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /> <a href="https://commons.wikimedia.org/wiki/Category:Astrobiology" class="extiw" title="commons:Category:Astrobiology">Commons</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="Molecules_detected_in_outer_space" 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:Molecules_detected_in_outer_space" title="Template:Molecules detected in outer space"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Molecules_detected_in_outer_space" title="Template talk:Molecules detected in outer space"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Molecules_detected_in_outer_space" title="Special:EditPage/Template:Molecules detected in outer space"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Molecules_detected_in_outer_space" style="font-size:114%;margin:0 4em"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules" title="List of interstellar and circumstellar molecules">Molecules detected in outer space</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Molecule" title="Molecule">Molecules</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/Diatomic_molecule" title="Diatomic molecule">Diatomic</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/Aluminium_monochloride" title="Aluminium monochloride">Aluminium monochloride</a></li> <li><a href="/wiki/Aluminium_monofluoride" title="Aluminium monofluoride">Aluminium monofluoride</a></li> <li><a href="/wiki/Aluminium(II)_oxide" title="Aluminium(II) oxide">Aluminium(II) oxide</a></li> <li><a href="/wiki/Argonium" title="Argonium">Argonium</a></li> <li><a href="/wiki/Carbon_cation" class="mw-redirect" title="Carbon cation">Carbon cation</a></li> <li><a href="/wiki/Carbon_monophosphide" title="Carbon monophosphide">Carbon monophosphide</a></li> <li><a href="/wiki/Carbon_monosulfide" title="Carbon monosulfide">Carbon monosulfide</a></li> <li><a href="/wiki/Carbon_monoxide" title="Carbon monoxide">Carbon monoxide</a></li> <li><a href="/wiki/Cyano_radical" title="Cyano radical">Cyano radical</a></li> <li><a href="/wiki/Diatomic_carbon" title="Diatomic carbon">Diatomic carbon</a></li> <li><a href="/w/index.php?title=Fluoromethylidynium&action=edit&redlink=1" class="new" title="Fluoromethylidynium (page does not exist)">Fluoromethylidynium</a></li> <li><a href="/wiki/Helium_hydride_ion" title="Helium hydride ion">Helium hydride ion</a></li> <li><a href="/wiki/Hydrogen_chloride" title="Hydrogen chloride">Hydrogen chloride</a></li> <li><a href="/wiki/Hydrogen_fluoride" title="Hydrogen fluoride">Hydrogen fluoride</a></li> <li><a href="/wiki/Hydrogen" title="Hydrogen">Hydrogen</a> (molecular)</li> <li><a href="/wiki/Hydroxyl_radical" title="Hydroxyl radical">Hydroxyl radical</a></li> <li><a href="/wiki/Iron(II)_oxide" title="Iron(II) oxide">Iron(II) oxide</a></li> <li><a href="/wiki/Magnesium_monohydride" title="Magnesium monohydride">Magnesium monohydride</a></li> <li><a href="/wiki/Methylidyne_radical" title="Methylidyne radical">Methylidyne radical</a></li> <li><a href="/wiki/Nitric_oxide" title="Nitric oxide">Nitric oxide</a></li> <li><a href="/wiki/Nitrogen" title="Nitrogen">Nitrogen</a> (molecular)</li> <li><a href="/wiki/Imidogen" title="Imidogen">Imidogen</a></li> <li><a href="/wiki/Sulfur_mononitride" title="Sulfur mononitride">Sulfur mononitride</a></li> <li><a href="/wiki/Oxygen" title="Oxygen">Oxygen</a> (molecular)</li> <li><a href="/wiki/Phosphorus_monoxide" title="Phosphorus monoxide">Phosphorus monoxide</a></li> <li><a href="/wiki/Phosphorus_mononitride" title="Phosphorus mononitride">Phosphorus mononitride</a></li> <li><a href="/wiki/Potassium_chloride" title="Potassium chloride">Potassium chloride</a></li> <li><a href="/wiki/Silicon_carbide" title="Silicon carbide">Silicon carbide</a></li> <li><a href="/wiki/Silicon_monoxide" title="Silicon monoxide">Silicon monoxide</a></li> <li><a href="/wiki/Silicon_monosulfide" title="Silicon monosulfide">Silicon monosulfide</a></li> <li><a href="/wiki/Sodium_chloride" title="Sodium chloride">Sodium chloride</a></li> <li><a href="/wiki/Sodium_iodide" title="Sodium iodide">Sodium iodide</a></li> <li><a href="/wiki/Sulfanyl" title="Sulfanyl">Sulfanyl</a></li> <li><a href="/wiki/Sulfur_monoxide" title="Sulfur monoxide">Sulfur monoxide</a></li> <li><a href="/wiki/Titanium(II)_oxide" title="Titanium(II) oxide">Titanium(II) oxide</a></li></ul> </div></td><td class="noviewer navbox-image" rowspan="9" style="width:1px;padding:0 0 0 2px"><div><a href="/wiki/Nitrous_oxide" title="Nitrous oxide"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Nitrous-oxide-3D-balls.png/60px-Nitrous-oxide-3D-balls.png" decoding="async" width="60" height="24" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Nitrous-oxide-3D-balls.png/90px-Nitrous-oxide-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/93/Nitrous-oxide-3D-balls.png/120px-Nitrous-oxide-3D-balls.png 2x" data-file-width="1100" data-file-height="441" /></a> <a href="/wiki/Ethanol" title="Ethanol"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b0/Ethanol-3D-balls.png/60px-Ethanol-3D-balls.png" decoding="async" width="60" height="41" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b0/Ethanol-3D-balls.png/90px-Ethanol-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b0/Ethanol-3D-balls.png/120px-Ethanol-3D-balls.png 2x" data-file-width="1100" data-file-height="754" /></a> <a href="/wiki/Buckminsterfullerene" title="Buckminsterfullerene"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0f/Buckminsterfullerene-perspective-3D-balls.png/60px-Buckminsterfullerene-perspective-3D-balls.png" decoding="async" width="60" height="63" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0f/Buckminsterfullerene-perspective-3D-balls.png/90px-Buckminsterfullerene-perspective-3D-balls.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0f/Buckminsterfullerene-perspective-3D-balls.png/120px-Buckminsterfullerene-perspective-3D-balls.png 2x" data-file-width="1056" data-file-height="1100" /></a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Triatomic_molecule" title="Triatomic molecule">Triatomic</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/Aluminium(I)_hydroxide" class="mw-redirect" title="Aluminium(I) hydroxide">Aluminium(I) hydroxide</a></li> <li><a href="/w/index.php?title=Aluminium_isocyanide&action=edit&redlink=1" class="new" title="Aluminium isocyanide (page does not exist)">Aluminium isocyanide</a></li> <li><a href="/wiki/Amino_radical" title="Amino radical">Amino radical</a></li> <li><a href="/wiki/Carbon_dioxide" title="Carbon dioxide">Carbon dioxide</a></li> <li><a href="/wiki/Carbonyl_sulfide" title="Carbonyl sulfide">Carbonyl sulfide</a></li> <li><a href="/w/index.php?title=CCP_radical&action=edit&redlink=1" class="new" title="CCP radical (page does not exist)">CCP radical</a></li> <li><a href="/wiki/Halonium_ion" title="Halonium ion">Chloronium</a></li> <li><a href="/wiki/Diazenylium" title="Diazenylium">Diazenylium</a></li> <li><a href="/wiki/Dicarbon_monoxide" title="Dicarbon monoxide">Dicarbon monoxide</a></li> <li><a href="/w/index.php?title=Disilicon_carbide&action=edit&redlink=1" class="new" title="Disilicon carbide (page does not exist)">Disilicon carbide</a></li> <li><a href="/wiki/Ethynyl_radical" title="Ethynyl radical">Ethynyl radical</a></li> <li><a href="/w/index.php?title=Formyl_radical&action=edit&redlink=1" class="new" title="Formyl radical (page does not exist)">Formyl radical</a></li> <li><a href="/wiki/Hydrogen_cyanide" title="Hydrogen cyanide">Hydrogen cyanide</a> (HCN)</li> <li><a href="/wiki/Hydrogen_isocyanide" title="Hydrogen isocyanide">Hydrogen isocyanide</a> (HNC)</li> <li><a href="/wiki/Hydrogen_sulfide" title="Hydrogen sulfide">Hydrogen sulfide</a></li> <li><a href="/wiki/Hydroperoxyl" title="Hydroperoxyl">Hydroperoxyl</a></li> <li><a href="/w/index.php?title=Iron_cyanide&action=edit&redlink=1" class="new" title="Iron cyanide (page does not exist)">Iron cyanide</a></li> <li><a href="/w/index.php?title=Isoformyl&action=edit&redlink=1" class="new" title="Isoformyl (page does not exist)">Isoformyl</a></li> <li><a href="/wiki/Magnesium_cyanide" title="Magnesium cyanide">Magnesium cyanide</a></li> <li><a href="/w/index.php?title=Magnesium_isocyanide&action=edit&redlink=1" class="new" title="Magnesium isocyanide (page does not exist)">Magnesium isocyanide</a></li> <li><a href="/wiki/Methylene_(compound)" title="Methylene (compound)">Methylene</a></li> <li><a href="/wiki/Diazenylium" title="Diazenylium">N2H+</a></li> <li><a href="/wiki/Nitrous_oxide" title="Nitrous oxide">Nitrous oxide</a></li> <li><a href="/wiki/Nitroxyl" title="Nitroxyl">Nitroxyl</a></li> <li><a href="/wiki/Ozone" title="Ozone">Ozone</a></li> <li><a href="/wiki/Methylidynephosphane" title="Methylidynephosphane">Methylidynephosphane</a></li> <li><a href="/wiki/Potassium_cyanide" title="Potassium cyanide">Potassium cyanide</a></li> <li><a href="/wiki/Trihydrogen_cation" title="Trihydrogen cation">Trihydrogen cation</a></li> <li><a href="/wiki/Sodium_cyanide" title="Sodium cyanide">Sodium cyanide</a></li> <li><a href="/wiki/Sodium_hydroxide" title="Sodium hydroxide">Sodium hydroxide</a></li> <li><a href="/w/index.php?title=Silicon_carbonitride&action=edit&redlink=1" class="new" title="Silicon carbonitride (page does not exist)">Silicon carbonitride</a></li> <li><a href="/w/index.php?title=C-Silicon_dicarbide&action=edit&redlink=1" class="new" title="C-Silicon dicarbide (page does not exist)">c-Silicon dicarbide</a></li> <li><a href="/w/index.php?title=SiNC&action=edit&redlink=1" class="new" title="SiNC (page does not exist)">SiNC</a></li> <li><a href="/wiki/Sulfur_dioxide" title="Sulfur dioxide">Sulfur dioxide</a></li> <li><a href="/w/index.php?title=Thioformyl&action=edit&redlink=1" class="new" title="Thioformyl (page does not exist)">Thioformyl</a></li> <li><a href="/wiki/Thioxoethenylidene" title="Thioxoethenylidene">Thioxoethenylidene</a></li> <li><a href="/wiki/Titanium_dioxide" title="Titanium dioxide">Titanium dioxide</a></li> <li><a href="/wiki/Tricarbon" title="Tricarbon">Tricarbon</a></li> <li><a href="/wiki/Water" title="Water">Water</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Four atoms</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/Acetylene" title="Acetylene">Acetylene</a></li> <li><a href="/wiki/Ammonia" title="Ammonia">Ammonia</a></li> <li><a href="/wiki/Isocyanic_acid" title="Isocyanic acid">Isocyanic acid</a></li> <li><a href="/wiki/Polyyne" title="Polyyne">Cyanoethynyl</a></li> <li><a href="/wiki/Interstellar_formaldehyde" title="Interstellar formaldehyde">Formaldehyde</a></li> <li><a href="/wiki/Fulminic_acid" title="Fulminic acid">Fulminic acid</a></li> <li><a href="/w/index.php?title=HCCN&action=edit&redlink=1" class="new" title="HCCN (page does not exist)">HCCN</a></li> <li><a href="/wiki/Hydrogen_peroxide" title="Hydrogen peroxide">Hydrogen peroxide</a></li> <li><a href="/w/index.php?title=Hydromagnesium_isocyanide&action=edit&redlink=1" class="new" title="Hydromagnesium isocyanide (page does not exist)">Hydromagnesium isocyanide</a></li> <li><a href="/wiki/Isocyanic_acid" title="Isocyanic acid">Isocyanic acid</a></li> <li><a href="/wiki/Thiocyanic_acid" title="Thiocyanic acid">Isothiocyanic acid</a></li> <li><a href="/w/index.php?title=Ketenyl&action=edit&redlink=1" class="new" title="Ketenyl (page does not exist)">Ketenyl</a></li> <li><a href="/w/index.php?title=Methylene_amidogen&action=edit&redlink=1" class="new" title="Methylene amidogen (page does not exist)">Methylene amidogen</a></li> <li><a href="/wiki/Methyl_cation" class="mw-redirect" title="Methyl cation">Methyl cation</a></li> <li><a href="/wiki/Methyl_radical" title="Methyl radical">Methyl radical</a></li> <li><a href="/wiki/Propynylidyne" title="Propynylidyne">Propynylidyne</a></li> <li><a href="/w/index.php?title=Protonated_carbon_dioxide&action=edit&redlink=1" class="new" title="Protonated carbon dioxide (page does not exist)">Protonated carbon dioxide</a></li> <li><a href="/wiki/Protonated_hydrogen_cyanide" title="Protonated hydrogen cyanide">Protonated hydrogen cyanide</a></li> <li><a href="/w/index.php?title=Silicon_tricarbide&action=edit&redlink=1" class="new" title="Silicon tricarbide (page does not exist)">Silicon tricarbide</a></li> <li><a href="/wiki/Thioformaldehyde" title="Thioformaldehyde">Thioformaldehyde</a></li> <li><a href="/wiki/Tricarbon_monoxide" title="Tricarbon monoxide">Tricarbon monoxide</a></li> <li><a href="/wiki/Tricarbon_monosulfide" title="Tricarbon monosulfide">Tricarbon monosulfide</a></li> <li><a href="/wiki/Thiocyanic_acid" title="Thiocyanic acid">Thiocyanic acid</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Five atoms</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/Ammonium" title="Ammonium">Ammonium</a> ion</li> <li><a href="/wiki/Polyyne" title="Polyyne">Butadiynyl</a></li> <li><a href="/wiki/Carbodiimide" title="Carbodiimide">Carbodiimide</a></li> <li><a href="/wiki/Cyanamide" title="Cyanamide">Cyanamide</a></li> <li><a href="/wiki/Cyanoacetylene" title="Cyanoacetylene">Cyanoacetylene</a></li> <li><a href="/w/index.php?title=Cyanoformaldehyde&action=edit&redlink=1" class="new" title="Cyanoformaldehyde (page does not exist)">Cyanoformaldehyde</a></li> <li><a href="/wiki/Cyanomethyl" title="Cyanomethyl">Cyanomethyl</a></li> <li><a href="/wiki/Cyclopropenylidene" title="Cyclopropenylidene">Cyclopropenylidene</a></li> <li><a href="/wiki/Formic_acid" title="Formic acid">Formic acid</a></li> <li><a href="/w/index.php?title=Isocyanoacetylene&action=edit&redlink=1" class="new" title="Isocyanoacetylene (page does not exist)">Isocyanoacetylene</a></li> <li><a href="/wiki/Ketene" title="Ketene">Ketene</a></li> <li><a href="/wiki/Methane" title="Methane">Methane</a></li> <li><a href="/wiki/Methoxy" class="mw-redirect" title="Methoxy">Methoxy radical</a></li> <li><a href="/w/index.php?title=Methylenimine&action=edit&redlink=1" class="new" title="Methylenimine (page does not exist)">Methylenimine</a></li> <li><a href="/w/index.php?title=Propadienylidene&action=edit&redlink=1" class="new" title="Propadienylidene (page does not exist)">Propadienylidene</a></li> <li><a href="/w/index.php?title=Protonated_formaldehyde&action=edit&redlink=1" class="new" title="Protonated formaldehyde (page does not exist)">Protonated formaldehyde</a></li> <li><a href="/wiki/Silane" title="Silane">Silane</a></li> <li><a href="/w/index.php?title=Silicon-carbide_cluster&action=edit&redlink=1" class="new" title="Silicon-carbide cluster (page does not exist)">Silicon-carbide cluster</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Six atoms</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/Acetonitrile" title="Acetonitrile">Acetonitrile</a></li> <li><a href="/w/index.php?title=Cyanobutadiynyl_radical&action=edit&redlink=1" class="new" title="Cyanobutadiynyl radical (page does not exist)">Cyanobutadiynyl radical</a></li> <li><a href="/w/index.php?title=E-Cyanomethanimine&action=edit&redlink=1" class="new" title="E-Cyanomethanimine (page does not exist)">E-Cyanomethanimine</a></li> <li><a href="/wiki/Cyclopropenone" title="Cyclopropenone">Cyclopropenone</a></li> <li><a href="/wiki/Diacetylene" title="Diacetylene">Diacetylene</a></li> <li><a href="/wiki/Ethylene" title="Ethylene">Ethylene</a></li> <li><a href="/wiki/Formamide" title="Formamide">Formamide</a></li> <li><a href="/w/index.php?title=HC4N&action=edit&redlink=1" class="new" title="HC4N (page does not exist)">HC4N</a></li> <li><a href="/wiki/Ketenimine" class="mw-redirect" title="Ketenimine">Ketenimine</a></li> <li><a href="/wiki/Methanethiol" title="Methanethiol">Methanethiol</a></li> <li><a href="/wiki/Methanol" title="Methanol">Methanol</a></li> <li><a href="/wiki/Methyl_isocyanide" title="Methyl isocyanide">Methyl isocyanide</a></li> <li><a href="/wiki/Polyyne" title="Polyyne">Pentynylidyne</a></li> <li><a href="/wiki/Propynal" class="mw-redirect" title="Propynal">Propynal</a></li> <li><a href="/w/index.php?title=Protonated_cyanoacetylene&action=edit&redlink=1" class="new" title="Protonated cyanoacetylene (page does not exist)">Protonated cyanoacetylene</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Seven atoms</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/Acetaldehyde" title="Acetaldehyde">Acetaldehyde</a></li> <li><a href="/wiki/Acrylonitrile" title="Acrylonitrile">Acrylonitrile</a> <ul><li><a href="/wiki/Vinyl_cyanide" class="mw-redirect" title="Vinyl cyanide">Vinyl cyanide</a></li></ul></li> <li><a href="/wiki/Cyanopolyyne" title="Cyanopolyyne">Cyanodiacetylene</a></li> <li><a href="/wiki/Ethylene_oxide" title="Ethylene oxide">Ethylene oxide</a></li> <li><a href="/wiki/Glycolonitrile" title="Glycolonitrile">Glycolonitrile</a></li> <li><a href="/wiki/Hexatriynyl_radical" title="Hexatriynyl radical">Hexatriynyl radical</a></li> <li><a href="/wiki/Propyne" title="Propyne">Propyne</a></li> <li><a href="/wiki/Methylamine" title="Methylamine">Methylamine</a></li> <li><a href="/wiki/Methyl_isocyanate" title="Methyl isocyanate">Methyl isocyanate</a></li> <li><a href="/wiki/Vinyl_alcohol" title="Vinyl alcohol">Vinyl alcohol</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Eight atoms</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/Acetic_acid" title="Acetic acid">Acetic acid</a></li> <li><a href="/wiki/Aminoacetonitrile" title="Aminoacetonitrile">Aminoacetonitrile</a></li> <li><a href="/w/index.php?title=Cyanoallene&action=edit&redlink=1" class="new" title="Cyanoallene (page does not exist)">Cyanoallene</a></li> <li><a href="/wiki/Ethanimine" title="Ethanimine">Ethanimine</a></li> <li><a href="/wiki/Glycolaldehyde" title="Glycolaldehyde">Glycolaldehyde</a></li> <li><a href="/wiki/Polyyne" title="Polyyne">Hexapentaenylidene</a></li> <li><a href="/wiki/Polyyne" title="Polyyne">Methylcyanoacetylene</a></li> <li><a href="/wiki/Methyl_formate" title="Methyl formate">Methyl formate</a></li> <li><a href="/wiki/Acrolein" title="Acrolein">Acrolein</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Nine atoms</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/Acetamide" title="Acetamide">Acetamide</a></li> <li><a href="/wiki/Cyanopolyyne" title="Cyanopolyyne">Cyanohexatriyne</a></li> <li><a href="/wiki/Dimethyl_ether" title="Dimethyl ether">Dimethyl ether</a></li> <li><a href="/wiki/Ethanol" title="Ethanol">Ethanol</a></li> <li><a href="/wiki/Polyyne" title="Polyyne">Methyldiacetylene</a></li> <li><a href="/wiki/Octatetraynyl_radical" title="Octatetraynyl radical">Octatetraynyl radical</a></li> <li><a href="/wiki/Propene" class="mw-redirect" title="Propene">Propene</a></li> <li><a href="/wiki/Ethanethiol" title="Ethanethiol">Ethanethiol</a></li> <li><a href="/wiki/Propionitrile" title="Propionitrile">Propionitrile</a></li> <li><a href="/wiki/N-Methylformamide" title="N-Methylformamide">N-Methylformamide</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Ten atoms or more</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/Acetone" title="Acetone">Acetone</a></li> <li><a href="/wiki/Benzene" title="Benzene">Benzene</a></li> <li><a href="/wiki/Benzonitrile" title="Benzonitrile">Benzonitrile</a></li> <li><a href="/wiki/Buckminsterfullerene" title="Buckminsterfullerene">Buckminsterfullerene</a> (C60, C60+, fullerene, buckyball)</li> <li><a href="/wiki/C70_fullerene" title="C70 fullerene">C70 fullerene</a></li> <li><a href="/wiki/Cyanopolyyne" title="Cyanopolyyne">Cyanodecapentayne</a></li> <li><a href="/wiki/Ethylene_glycol" title="Ethylene glycol">Ethylene glycol</a></li> <li><a href="/wiki/Ethyl_formate" title="Ethyl formate">Ethyl formate</a></li> <li><a href="/wiki/Methyl_acetate" title="Methyl acetate">Methyl acetate</a></li> <li><a href="/wiki/Cyanopolyyne" title="Cyanopolyyne">Methyl-cyano-diacetylene</a></li> <li><a href="/wiki/Polyyne" title="Polyyne">Methyltriacetylene</a></li> <li><a href="/wiki/Propionaldehyde" title="Propionaldehyde">Propionaldehyde</a></li> <li><a href="/wiki/Butyronitrile" title="Butyronitrile">Butyronitrile</a></li> <li><a href="/wiki/Pyrimidine" title="Pyrimidine">Pyrimidine</a></li> <li><a href="/w/index.php?title=Heptatrienyl_radical&action=edit&redlink=1" class="new" title="Heptatrienyl radical (page does not exist)">Heptatrienyl radical</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/Deuterium" title="Deuterium">Deuterated</a> molecules</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/Ammonia" title="Ammonia">Ammonia</a></li> <li><a href="/wiki/Ammonium" title="Ammonium">Ammonium</a> ion</li> <li><a href="/wiki/Formaldehyde" title="Formaldehyde">Formaldehyde</a></li> <li><a href="/wiki/Interstellar_formaldehyde#Interstellar_reactions" title="Interstellar formaldehyde">Formyl radical</a></li> <li><a href="/wiki/Heavy_water" title="Heavy water">Heavy water</a></li> <li><a href="/wiki/Hydrogen_cyanide" title="Hydrogen cyanide">Hydrogen cyanide</a></li> <li><a href="/wiki/Hydrogen_deuteride" title="Hydrogen deuteride">Hydrogen deuteride</a></li> <li><a href="/wiki/Hydrogen_isocyanide" title="Hydrogen isocyanide">Hydrogen isocyanide</a></li> <li><a href="/wiki/Propyne" title="Propyne">Propyne</a></li> <li><a href="/wiki/Diazenylium" title="Diazenylium">N2D+</a></li> <li><a href="/wiki/Trihydrogen_cation" title="Trihydrogen cation">Trihydrogen cation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#Molecules" title="List of interstellar and circumstellar molecules">Unconfirmed</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/Anthracene" title="Anthracene">Anthracene</a></li> <li><a href="/wiki/Dihydroxyacetone" title="Dihydroxyacetone">Dihydroxyacetone</a></li> <li><a href="/wiki/Methoxyethane" title="Methoxyethane">Methoxyethane</a></li> <li><a href="/wiki/Glycine" title="Glycine">Glycine</a></li> <li><a href="/wiki/Graphene" title="Graphene">Graphene</a></li> <li><a href="/wiki/Hemolithin" title="Hemolithin">Hemolithin</a></li> <li><a href="/w/index.php?title=H2NCO%2B&action=edit&redlink=1" class="new" title="H2NCO+ (page does not exist)">H2NCO+</a></li> <li><a href="/wiki/Carbon" title="Carbon">Linear C5</a></li> <li><a href="/wiki/Naphthalene" title="Naphthalene">Naphthalene cation</a></li> <li><a href="/wiki/Phosphine" title="Phosphine">Phosphine</a></li> <li><a href="/wiki/Pyrene" title="Pyrene">Pyrene</a></li> <li><a href="/wiki/Silylidyne" title="Silylidyne">Silylidyne</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/List_of_interstellar_and_circumstellar_molecules#See_also" title="List of interstellar and circumstellar molecules">Related</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/Abiogenesis" title="Abiogenesis">Abiogenesis</a></li> <li><a href="/wiki/Astrobiology" title="Astrobiology">Astrobiology</a></li> <li><a href="/wiki/Astrochemistry" title="Astrochemistry">Astrochemistry</a></li> <li><a href="/wiki/Atomic_and_molecular_astrophysics" title="Atomic and molecular astrophysics">Atomic and molecular astrophysics</a></li> <li><a href="/wiki/Chemical_formula" title="Chemical formula">Chemical formula</a></li> <li><a href="/wiki/Circumstellar_dust" title="Circumstellar dust">Circumstellar dust</a></li> <li><a href="/wiki/Circumstellar_envelope" title="Circumstellar envelope">Circumstellar envelope</a></li> <li><a href="/wiki/Cosmic_dust" title="Cosmic dust">Cosmic dust</a></li> <li><a href="/wiki/Cosmic_ray" title="Cosmic ray">Cosmic ray</a></li> <li><a href="/wiki/Cosmochemistry" title="Cosmochemistry">Cosmochemistry</a></li> <li><a href="/wiki/Diffuse_interstellar_band" class="mw-redirect" title="Diffuse interstellar band">Diffuse interstellar band</a></li> <li><a href="/wiki/Earliest_known_life_forms" title="Earliest known life forms">Earliest known life forms</a></li> <li><a class="mw-selflink selflink">Extraterrestrial life</a></li> <li><a href="/wiki/Extraterrestrial_liquid_water" title="Extraterrestrial liquid water">Extraterrestrial liquid water</a></li> <li><a href="/wiki/Forbidden_mechanism" title="Forbidden mechanism">Forbidden mechanism</a></li> <li><a href="/wiki/Homochirality" title="Homochirality">Homochirality</a></li> <li><a href="/wiki/Intergalactic_dust" title="Intergalactic dust">Intergalactic dust</a></li> <li><a href="/wiki/Interplanetary_medium" title="Interplanetary medium">Interplanetary medium</a></li> <li><a href="/wiki/Interstellar_medium" title="Interstellar medium">Interstellar medium</a></li> <li><a href="/wiki/Photodissociation_region" title="Photodissociation region">Photodissociation region</a></li> <li><a href="/wiki/Iron%E2%80%93sulfur_world_theory" class="mw-redirect" title="Iron–sulfur world theory">Iron–sulfur world theory</a></li> <li><a href="/wiki/Kerogen" title="Kerogen">Kerogen</a></li> <li><a href="/wiki/Molecules_in_stars" title="Molecules in stars">Molecules in stars</a></li> <li><a href="/wiki/Nexus_for_Exoplanet_System_Science" title="Nexus for Exoplanet System Science">Nexus for Exoplanet System Science</a></li> <li><a href="/wiki/Organic_compound" title="Organic compound">Organic compound</a></li> <li><a href="/wiki/Outer_space" title="Outer space">Outer space</a></li> <li><a href="/wiki/PAH_world_hypothesis" title="PAH world hypothesis">PAH world hypothesis</a></li> <li><a href="/wiki/Pseudo-panspermia" title="Pseudo-panspermia">Pseudo-panspermia</a></li> <li><a href="/wiki/Polycyclic_aromatic_hydrocarbon" title="Polycyclic aromatic hydrocarbon">Polycyclic aromatic hydrocarbon</a> (PAH)</li> <li><a href="/wiki/RNA_world_hypothesis" class="mw-redirect" title="RNA world hypothesis">RNA world hypothesis</a></li> <li><a href="/wiki/Spectroscopy" title="Spectroscopy">Spectroscopy</a></li> <li><a href="/wiki/Tholin" title="Tholin">Tholin</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2" style="font-weight: bold;"><div> <ul><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:Astrochemistry" title="Category:Astrochemistry">Category:Astrochemistry</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Earth-moon.jpg/16px-Earth-moon.jpg" decoding="async" width="16" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Earth-moon.jpg/24px-Earth-moon.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5c/Earth-moon.jpg/32px-Earth-moon.jpg 2x" data-file-width="3000" data-file-height="2400" /> <a href="/wiki/Portal:Outer_space" title="Portal:Outer space">Outer space portal</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/16px-Crab_Nebula.jpg" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/24px-Crab_Nebula.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/32px-Crab_Nebula.jpg 2x" data-file-width="3864" data-file-height="3864" /> <a href="/wiki/Portal:Astronomy" title="Portal:Astronomy">Astronomy portal</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Papapishu-Lab-icon-6.svg/16px-Papapishu-Lab-icon-6.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Papapishu-Lab-icon-6.svg/24px-Papapishu-Lab-icon-6.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Papapishu-Lab-icon-6.svg/32px-Papapishu-Lab-icon-6.svg.png 2x" data-file-width="512" data-file-height="512" /> <a href="/wiki/Portal:Chemistry" title="Portal:Chemistry">Chemistry portal</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="Interstellar_communications" 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" 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:Interstellar_messages" title="Template:Interstellar messages"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Interstellar_messages" title="Template talk:Interstellar messages"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Interstellar_messages" title="Special:EditPage/Template:Interstellar messages"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Interstellar_communications" style="font-size:114%;margin:0 4em"><a href="/wiki/Interstellar_communication" title="Interstellar communication">Interstellar communications</a></div></th></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Programs</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/Active_SETI" title="Active SETI">Active SETI</a></li> <li><a href="/wiki/Breakthrough_Initiatives" title="Breakthrough Initiatives">Breakthrough Initiatives</a> <ul><li><a href="/wiki/Breakthrough_Listen" title="Breakthrough Listen">Breakthrough Listen</a></li> <li><a href="/wiki/Breakthrough_Message" class="mw-redirect" title="Breakthrough Message">Breakthrough Message</a></li></ul></li> <li><a href="/wiki/Communication_with_extraterrestrial_intelligence" title="Communication with extraterrestrial intelligence">Communication with extraterrestrial intelligence</a></li> <li><a href="/wiki/Search_for_extraterrestrial_intelligence" title="Search for extraterrestrial intelligence">Search for extraterrestrial intelligence</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Messages</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_interstellar_radio_messages" title="List of interstellar radio messages">List of interstellar radio messages</a></li> <li><a href="/wiki/A_Message_from_Earth" class="mw-redirect" title="A Message from Earth">A Message from Earth</a></li> <li><a href="/wiki/Across_the_Universe_(message)" title="Across the Universe (message)">Across the Universe</a></li> <li><a href="/wiki/Arecibo_message" title="Arecibo message">Arecibo message</a></li> <li><a href="/wiki/Bracewell_probe" title="Bracewell probe">Bracewell probe</a></li> <li><a href="/wiki/Cosmic_Call" title="Cosmic Call">Cosmic Call</a></li> <li><a href="/wiki/CosmicOS" title="CosmicOS">CosmicOS</a></li> <li><a href="/wiki/Hello_from_Earth" class="mw-redirect" title="Hello from Earth">Hello from Earth</a></li> <li><a href="/wiki/Pioneer_plaque" title="Pioneer plaque">Pioneer plaque</a></li> <li><a href="/wiki/Teen_Age_Message" title="Teen Age Message">Teen Age Message</a></li> <li><a href="/wiki/Voyager_Golden_Record" title="Voyager Golden Record">Voyager Golden Record</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">People</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/Frank_Drake" title="Frank Drake">Frank Drake</a></li> <li><a href="/wiki/Ann_Druyan" title="Ann Druyan">Ann Druyan</a></li> <li><a href="/wiki/Hans_Freudenthal" title="Hans Freudenthal">Hans Freudenthal</a></li> <li><a href="/wiki/Sebastian_von_Hoerner" title="Sebastian von Hoerner">Sebastian von Hoerner</a></li> <li><a href="/wiki/Nikolai_Kardashev" title="Nikolai Kardashev">Nikolai Kardashev</a></li> <li><a href="/wiki/Jon_Lomberg" title="Jon Lomberg">Jon Lomberg</a></li> <li><a href="/wiki/Carl_Sagan" title="Carl Sagan">Carl Sagan</a></li> <li><a href="/wiki/Linda_Salzman_Sagan" title="Linda Salzman Sagan">Linda Salzman Sagan</a></li> <li><a href="/wiki/Iosif_Shklovsky" title="Iosif Shklovsky">Iosif Shklovsky</a></li> <li><a href="/wiki/Aleksandr_Leonidovich_Zaitsev" class="mw-redirect" title="Aleksandr Leonidovich Zaitsev">Aleksandr Zaitsev</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="text-align: center;;width:1%">Other</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/Alien_language" title="Alien language">Alien language</a></li> <li><a href="/wiki/Archaeology,_Anthropology,_and_Interstellar_Communication" title="Archaeology, Anthropology, and Interstellar Communication">Archaeology, Anthropology, and Interstellar Communication</a></li> <li><a href="/wiki/Astrobiology" title="Astrobiology">Astrobiology</a></li> <li><a href="/wiki/Astrolinguistics" title="Astrolinguistics">Astrolinguistics</a></li> <li><a href="/wiki/Drake_equation" title="Drake equation">Drake equation</a></li> <li><a class="mw-selflink selflink">Extraterrestrial life</a></li> <li><a href="/wiki/Lincos_language" title="Lincos language">Lincos</a></li> <li><a href="/wiki/Fermi_paradox" title="Fermi paradox">Fermi paradox</a></li> <li><a href="/wiki/Prix_Guzman" title="Prix Guzman">Prix Guzman</a></li> <li><a href="/wiki/San_Marino_Scale" title="San Marino Scale">San Marino Scale</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow hlist" colspan="2" style="text-align: center;"><div> <ul><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:Interstellar_messages" title="Category:Interstellar messages">Category</a></li> <li><a href="/wiki/File:Symbol_portal_class.svg" class="mw-file-description" title="Portal"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/16px-Symbol_portal_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/23px-Symbol_portal_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/31px-Symbol_portal_class.svg.png 2x" data-file-width="180" data-file-height="185" /></a> <a href="/wiki/Portal:Space" class="mw-redirect" title="Portal:Space">Space Portal</a></li></ul> </div></td></tr></tbody></table></div> <style data-mw-deduplicate="TemplateStyles:r1130092004">.mw-parser-output .portal-bar{font-size:88%;font-weight:bold;display:flex;justify-content:center;align-items:baseline}.mw-parser-output .portal-bar-bordered{padding:0 2em;background-color:#fdfdfd;border:1px solid #a2a9b1;clear:both;margin:1em auto 0}.mw-parser-output .portal-bar-related{font-size:100%;justify-content:flex-start}.mw-parser-output .portal-bar-unbordered{padding:0 1.7em;margin-left:0}.mw-parser-output .portal-bar-header{margin:0 1em 0 0.5em;flex:0 0 auto;min-height:24px}.mw-parser-output .portal-bar-content{display:flex;flex-flow:row wrap;flex:0 1 auto;padding:0.15em 0;column-gap:1em;align-items:baseline;margin:0;list-style:none}.mw-parser-output .portal-bar-content-related{margin:0;list-style:none}.mw-parser-output .portal-bar-item{display:inline-block;margin:0.15em 0.2em;min-height:24px;line-height:24px}@media screen and (max-width:768px){.mw-parser-output .portal-bar{font-size:88%;font-weight:bold;display:flex;flex-flow:column wrap;align-items:baseline}.mw-parser-output .portal-bar-header{text-align:center;flex:0;padding-left:0.5em;margin:0 auto}.mw-parser-output .portal-bar-related{font-size:100%;align-items:flex-start}.mw-parser-output .portal-bar-content{display:flex;flex-flow:row wrap;align-items:center;flex:0;column-gap:1em;border-top:1px solid #a2a9b1;margin:0 auto;list-style:none}.mw-parser-output .portal-bar-content-related{border-top:none;margin:0;list-style:none}}.mw-parser-output .navbox+link+.portal-bar,.mw-parser-output .navbox+style+.portal-bar,.mw-parser-output .navbox+link+.portal-bar-bordered,.mw-parser-output .navbox+style+.portal-bar-bordered,.mw-parser-output .sister-bar+link+.portal-bar,.mw-parser-output .sister-bar+style+.portal-bar,.mw-parser-output .portal-bar+.navbox-styles+.navbox,.mw-parser-output .portal-bar+.navbox-styles+.sister-bar{margin-top:-1px}</style><div class="portal-bar noprint metadata noviewer portal-bar-bordered" role="navigation" aria-label="Portals"><a href="/wiki/Wikipedia:Contents/Portals" title="Wikipedia:Contents/Portals">Portals</a>:<ul class="portal-bar-content"><li class="portal-bar-item"><a href="/wiki/File:Issoria_lathonia.jpg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Issoria_lathonia.jpg/21px-Issoria_lathonia.jpg" decoding="async" width="21" height="15" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Issoria_lathonia.jpg/32px-Issoria_lathonia.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Issoria_lathonia.jpg/42px-Issoria_lathonia.jpg 2x" data-file-width="629" data-file-height="445" /></a> <a href="/wiki/Portal:Biology" title="Portal:Biology">Biology</a></li><li class="portal-bar-item"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/19px-Crab_Nebula.jpg" decoding="async" width="19" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/29px-Crab_Nebula.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/00/Crab_Nebula.jpg/38px-Crab_Nebula.jpg 2x" 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