Light Definition and 1000 Threads

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It may not display this or other websites correctly.<br />You should upgrade or use an <a href="https://www.google.com/chrome/" target="_blank" rel="noopener">alternative browser</a>.</div> <div class="p-body-main "> <div class="p-body-contentCol"></div> <div class="p-body-content"> <div class="p-body-pageContent"> <div class="p-breadcrumbs--parent "> <ul class="p-breadcrumbs " itemscope itemtype="https://schema.org/BreadcrumbList"> <li itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"> <a href="https://www.physicsforums.com/" itemprop="item"> <span itemprop="name">Forums</span> </a> <meta itemprop="position" content="1" /> </li> <li itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"> <a href="/tags/" itemprop="item"> <span itemprop="name">Tags</span> </a> <meta itemprop="position" content="2" /> </li> </ul> </div> <div class="p-body-header"> <div class="p-title "> <h1 class="p-title-value">Light Definition and 1000 Threads</h1> </div> </div> <div class="tabs tabs--standalone"> <div class="hScroller" data-xf-init="h-scroller"> <span class="hScroller-scroll"> <a class="tabs-tab is-active" href="/tags/light/">Recent contents</a> <a class="tabs-tab " href="/tags/light/wiki">View information</a> <a class="tabs-tab " href="/tags/light/top-users">Top users</a> </span> </div> </div> <div class="block" data-xf-init="" data-type="" data-href="/inline-mod/"> <div class="block-container"> <ol class="block-body"> <li class="block-row block-row--separated js-inlineModContainer" data-author="GR86"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/gr86.760017/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="760017" data-xf-init="member-tooltip" style="background-color: #29a385; color: #051411"> <span class="avatar-u760017-s" role="img" aria-label="GR86">G</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/theories-about-light-and-time-near-a-black-hole.1078715/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Theories about light and time near a black hole</a> </h3> <div class="contentRow-snippet">First off, i don't know if this has been discussed by other people openly, it was just something i have wondered for a long time. OK. The event horizon marks the distance, spherically, where anything moving at the speed of light (including light), has it's escape velocity overcome. So closer...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/gr86.760017/" class="username " dir="auto" data-user-id="760017" data-xf-init="member-tooltip">GR86</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-02-22T00:28:22-0600" data-time="1740205702" data-date-string="Feb 22, 2025" data-time-string="12:28 AM" title="Feb 22, 2025 at 12:28 AM">Today, 12:28 AM</time></li> <li> <dl class="tagList tagList--thread-1078715 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/event/" data-xf-init="preview-tooltip" data-preview-url="/tags/event/preview" class="tagItem tagItem--tag_event" dir="auto"> event </a> <a href="/tags/horizon/" data-xf-init="preview-tooltip" data-preview-url="/tags/horizon/preview" class="tagItem tagItem--tag_horizon" dir="auto"> Horizon </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 20</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="splatcube"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/splatcube.759697/" class="avatar avatar--s" data-user-id="759697" data-xf-init="member-tooltip"> <img src="/data/avatars/s/759/759697.jpg?1739917237" srcset="/data/avatars/m/759/759697.jpg?1739917237 2x" alt="splatcube" class="avatar-u759697-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-would-light-work-on-a-mirror-very-far-away.1078655/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>How would light work on a mirror very far away?</a> </h3> <div class="contentRow-snippet">Hello!! I'm still in school and not great with physics, but I'd really like to get into it. All of it seems so awesome and my dad is a partical physicist so I can usually ask him about any questions I have but I had one today he couldn't answer right away, he said he'd think about it and get...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/splatcube.759697/" class="username " dir="auto" data-user-id="759697" data-xf-init="member-tooltip">splatcube</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-02-18T16:20:40-0600" data-time="1739917240" data-date-string="Feb 18, 2025" data-time-string="4:20 PM" title="Feb 18, 2025 at 4:20 PM">Tuesday, 4:20 PM</time></li> <li> <dl class="tagList tagList--thread-1078655 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/mirror/" data-xf-init="preview-tooltip" data-preview-url="/tags/mirror/preview" class="tagItem tagItem--tag_mirror" dir="auto"> Mirror </a> <a href="/tags/telescope/" data-xf-init="preview-tooltip" data-preview-url="/tags/telescope/preview" class="tagItem tagItem--tag_telescope" dir="auto"> Telescope </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="LightningInAJar"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lightninginajar.681077/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="681077" data-xf-init="member-tooltip" style="background-color: #6699cc; color: #204060"> <span class="avatar-u681077-s" role="img" aria-label="LightningInAJar">L</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/using-primary-color-light-filters.1078404/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Using primary color light filters</a> </h3> <div class="contentRow-snippet">I wanted to try taking 3 camera images using red, green, and blue filters and combining them as color channels to see what that might look like. A) Should this produce more accurate colors, particularly in low light? B) Do they even sell filters that only let light pass that can activate the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lightninginajar.681077/" class="username " dir="auto" data-user-id="681077" data-xf-init="member-tooltip">LightningInAJar</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-02-04T20:26:47-0600" data-time="1738722407" data-date-string="Feb 4, 2025" data-time-string="8:26 PM" title="Feb 4, 2025 at 8:26 PM">Feb 4, 2025</time></li> <li> <dl class="tagList tagList--thread-1078404 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/filters/" data-xf-init="preview-tooltip" data-preview-url="/tags/filters/preview" class="tagItem tagItem--tag_filters" dir="auto"> Filters </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/photography/" data-xf-init="preview-tooltip" data-preview-url="/tags/photography/preview" class="tagItem tagItem--tag_photography" dir="auto"> Photography </a> </span> </dd> </dl> </li> <li>Replies: 20</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="songoku"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/songoku.171861/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="171861" data-xf-init="member-tooltip" style="background-color: #6666cc; color: #ececf9"> <span class="avatar-u171861-s" role="img" aria-label="songoku">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/correct-statement-about-light-transmitted-and-reflected-by-windscreen.1078317/">Correct statement about light transmitted and reflected by windscreen</a> </h3> <div class="contentRow-snippet">I don't really understand how to relate the question to the picture. Picture Y is taken using polarising filter but how can we know whether it is light transmitted or reflected because I think in both pictures there is light transmitted through the windscreen and there is also light reflected...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/songoku.171861/" class="username " dir="auto" data-user-id="171861" data-xf-init="member-tooltip">songoku</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-01-30T21:37:21-0600" data-time="1738294641" data-date-string="Jan 30, 2025" data-time-string="9:37 PM" title="Jan 30, 2025 at 9:37 PM">Jan 30, 2025</time></li> <li> <dl class="tagList tagList--thread-1078317 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/polarizer/" data-xf-init="preview-tooltip" data-preview-url="/tags/polarizer/preview" class="tagItem tagItem--tag_polarizer" dir="auto"> Polarizer </a> <a href="/tags/transmission/" data-xf-init="preview-tooltip" data-preview-url="/tags/transmission/preview" class="tagItem tagItem--tag_transmission" dir="auto"> Transmission </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="songoku"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/songoku.171861/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="171861" data-xf-init="member-tooltip" style="background-color: #6666cc; color: #ececf9"> <span class="avatar-u171861-s" role="img" aria-label="songoku">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/direction-of-oscillations-of-a-polarised-light-wave.1078299/">Direction of oscillations of a polarised light wave</a> </h3> <div class="contentRow-snippet">My answer is (C) because light can only travel in one direction after being polarised so the oscillation is also in the same direction as the direction of travel. Am I correct? Thanks</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/songoku.171861/" class="username " dir="auto" data-user-id="171861" data-xf-init="member-tooltip">songoku</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-01-30T00:35:36-0600" data-time="1738218936" data-date-string="Jan 30, 2025" data-time-string="12:35 AM" title="Jan 30, 2025 at 12:35 AM">Jan 30, 2025</time></li> <li> <dl class="tagList tagList--thread-1078299 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/oscillations/" data-xf-init="preview-tooltip" data-preview-url="/tags/oscillations/preview" class="tagItem tagItem--tag_oscillations" dir="auto"> Oscillations </a> </span> </dd> </dl> </li> <li>Replies: 12</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="sibir1us"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/sibir1us.758045/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="758045" data-xf-init="member-tooltip" style="background-color: #523314; color: #d18c47"> <span class="avatar-u758045-s" role="img" aria-label="sibir1us">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-accelerates-the-light-back-to-its-constant-speed.1078144/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>What accelerates the light back to its constant speed?</a> </h3> <div class="contentRow-snippet">For example, let's suppose that there is a drop of water in vacuum. The light travels with the constant speed of light, then enters through the drop of water, decelerates, since the density is different, then it exits back to vacuum, supposedly traveling with the constant speed of light in...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/sibir1us.758045/" class="username " dir="auto" data-user-id="758045" data-xf-init="member-tooltip">sibir1us</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-01-22T22:55:21-0600" data-time="1737608121" data-date-string="Jan 22, 2025" data-time-string="10:55 PM" title="Jan 22, 2025 at 10:55 PM">Jan 22, 2025</time></li> <li> <dl class="tagList tagList--thread-1078144 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/acceleration/" data-xf-init="preview-tooltip" data-preview-url="/tags/acceleration/preview" class="tagItem tagItem--tag_acceleration" dir="auto"> Acceleration </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed-of-light/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed-of-light/preview" class="tagItem tagItem--tag_speed-of-light" dir="auto"> Speed of <em class="textHighlight">light</em> </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/electromagnetism.302/">Electromagnetism</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Lari Santos"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lari-santos.757779/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="757779" data-xf-init="member-tooltip" style="background-color: #999933; color: #131306"> <span class="avatar-u757779-s" role="img" aria-label="Lari Santos">L</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-affects-light-near-black-holes-and-stars.1068205/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>What affects light near black holes and stars?</a> </h3> <div class="contentRow-snippet">I am a physics student and I have a question: What happens to light when it passes near a very massive object, like a star or a black hole?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lari-santos.757779/" class="username " dir="auto" data-user-id="757779" data-xf-init="member-tooltip">Lari Santos</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2025-01-18T09:28:12-0600" data-time="1737214092" data-date-string="Jan 18, 2025" data-time-string="9:28 AM" title="Jan 18, 2025 at 9:28 AM">Jan 18, 2025</time></li> <li> <dl class="tagList tagList--thread-1068205 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/black-hole/" data-xf-init="preview-tooltip" data-preview-url="/tags/black-hole/preview" class="tagItem tagItem--tag_black-hole" dir="auto"> Black hole </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/star/" data-xf-init="preview-tooltip" data-preview-url="/tags/star/preview" class="tagItem tagItem--tag_star" dir="auto"> Star </a> </span> </dd> </dl> </li> <li>Replies: 2</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Lightisslow"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lightisslow.756518/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="756518" data-xf-init="member-tooltip" style="background-color: #85a329; color: #111405"> <span class="avatar-u756518-s" role="img" aria-label="Lightisslow">L</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/c-2-in-einsteins-theory-of-relativity.1067808/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>c^2 in Einstein‘s theory of relativity</a> </h3> <div class="contentRow-snippet">C2 means the speed of light squared so Mass traveling at the speed of light times itself becomes energy. That would mean we could travel up to.34,500,000,000 miles per second before breaking down into pure energy. So we should be able to travel faster than the speed of life. Did I miss something?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lightisslow.756518/" class="username " dir="auto" data-user-id="756518" data-xf-init="member-tooltip">Lightisslow</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-12-31T02:21:47-0600" data-time="1735633307" data-date-string="Dec 31, 2024" data-time-string="2:21 AM" title="Dec 31, 2024 at 2:21 AM">Dec 31, 2024</time></li> <li> <dl class="tagList tagList--thread-1067808 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> <a href="/tags/theory/" data-xf-init="preview-tooltip" data-preview-url="/tags/theory/preview" class="tagItem tagItem--tag_theory" dir="auto"> Theory </a> </span> </dd> </dl> </li> <li>Replies: 10</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="lloydziegler"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lloydziegler.756433/" class="avatar avatar--s" data-user-id="756433" data-xf-init="member-tooltip"> <img src="/data/avatars/s/756/756433.jpg?1735501479" srcset="/data/avatars/m/756/756433.jpg?1735501479 2x" alt="lloydziegler" class="avatar-u756433-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/can-the-intersection-point-of-two-light-beams-exceed-the-speed-of-light.1067779/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Can the intersection point of two light beams exceed the speed of light?</a> </h3> <div class="contentRow-snippet">If two seperate, coherent light beams were to intersect at a slight angle near the viewer, and then very rapidly made parallel,could the intersection point move away from the viewer in excess of the speed of light? If so, could that intersection point be made visible somehow,and how would the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lloydziegler.756433/" class="username " dir="auto" data-user-id="756433" data-xf-init="member-tooltip">lloydziegler</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-12-29T13:55:22-0600" data-time="1735502122" data-date-string="Dec 29, 2024" data-time-string="1:55 PM" title="Dec 29, 2024 at 1:55 PM">Dec 29, 2024</time></li> <li> <dl class="tagList tagList--thread-1067779 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/intersection/" data-xf-init="preview-tooltip" data-preview-url="/tags/intersection/preview" class="tagItem tagItem--tag_intersection" dir="auto"> Intersection </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 9</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="FRANKENSTEIN54"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/frankenstein54.756197/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="756197" data-xf-init="member-tooltip" style="background-color: #ded3d3; color: #936c6c"> <span class="avatar-u756197-s" role="img" aria-label="FRANKENSTEIN54">F</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/speed-of-light-bullet.1067657/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Speed of Light & Bullet</a> </h3> <div class="contentRow-snippet">Everything has the speed it's moving at , at the time it's measured . Light always leaves its Source at the speed called "c" . That doesn't mean its Relative speed is always "c" for all observers .</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/frankenstein54.756197/" class="username " dir="auto" data-user-id="756197" data-xf-init="member-tooltip">FRANKENSTEIN54</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-12-23T21:46:54-0600" data-time="1735012014" data-date-string="Dec 23, 2024" data-time-string="9:46 PM" title="Dec 23, 2024 at 9:46 PM">Dec 23, 2024</time></li> <li> <dl class="tagList tagList--thread-1067657 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/bullet/" data-xf-init="preview-tooltip" data-preview-url="/tags/bullet/preview" class="tagItem tagItem--tag_bullet" dir="auto"> Bullet </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 72</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="metz"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/metz.755777/" class="avatar avatar--s" data-user-id="755777" data-xf-init="member-tooltip"> <img src="/data/avatars/s/755/755777.jpg?1733985284" srcset="/data/avatars/m/755/755777.jpg?1733985284 2x" alt="metz" class="avatar-u755777-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/controlling-optical-wavelength-of-illumination-to-improve-reproduction-rates-in-microorganisms.1067421/">Controlling optical wavelength of illumination to improve reproduction rates in microorganisms</a> </h3> <div class="contentRow-snippet">hello! I am trying to make a device that will improve reproduction rates in certain microorganisms that I am studying. They reproduce fastest under shorter wavelengths, specifically best at blue light. Any ideas for devices or materials that could help out would be appreciated! An idea I had was...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/metz.755777/" class="username " dir="auto" data-user-id="755777" data-xf-init="member-tooltip">metz</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-12-12T00:44:39-0600" data-time="1733985879" data-date-string="Dec 12, 2024" data-time-string="12:44 AM" title="Dec 12, 2024 at 12:44 AM">Dec 12, 2024</time></li> <li> <dl class="tagList tagList--thread-1067421 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/chemistry/" data-xf-init="preview-tooltip" data-preview-url="/tags/chemistry/preview" class="tagItem tagItem--tag_chemistry" dir="auto"> Chemistry </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/optics/" data-xf-init="preview-tooltip" data-preview-url="/tags/optics/preview" class="tagItem tagItem--tag_optics" dir="auto"> Optics </a> <a href="/tags/wavelengths/" data-xf-init="preview-tooltip" data-preview-url="/tags/wavelengths/preview" class="tagItem tagItem--tag_wavelengths" dir="auto"> Wavelengths </a> </span> </dd> </dl> </li> <li>Replies: 9</li> <li>Forum: <a href="/forums/biology-and-medical.82/">Biology and Medical</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Hamedi"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/hamedi.755029/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="755029" data-xf-init="member-tooltip" style="background-color: #d6995c; color: #66401a"> <span class="avatar-u755029-s" role="img" aria-label="Hamedi">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-can-i-create-a-mirror-reflection-illusion.1067029/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>How Can I Create a Mirror Reflection Illusion?</a> </h3> <div class="contentRow-snippet">please be specific about the number of mirrors I have to use and how large they should be and what angles they should be placed at. And how much light and where should I shed. Thank you. I also made a stupid doodle which I thought might help</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/hamedi.755029/" class="username " dir="auto" data-user-id="755029" data-xf-init="member-tooltip">Hamedi</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-11-20T02:41:15-0600" data-time="1732092075" data-date-string="Nov 20, 2024" data-time-string="2:41 AM" title="Nov 20, 2024 at 2:41 AM">Nov 20, 2024</time></li> <li> <dl class="tagList tagList--thread-1067029 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/mirrors/" data-xf-init="preview-tooltip" data-preview-url="/tags/mirrors/preview" class="tagItem tagItem--tag_mirrors" dir="auto"> Mirrors </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/optics.300/">Optics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Max364"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/max364.602921/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="602921" data-xf-init="member-tooltip" style="background-color: #999966; color: #2e2e1f"> <span class="avatar-u602921-s" role="img" aria-label="Max364">M</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/does-everything-move-at-the-speed-of-light.1067028/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Does everything move at the speed of light?</a> </h3> <div class="contentRow-snippet">...but is it correct to say: Speed² (in space) + Time² (in space) = 1 ?? derived using Pythagorus (explained at 10-13 minutes in)....the trade off between Speed and Time, at maximum speed Time is zero and at max Time, Speed would be zero.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/max364.602921/" class="username " dir="auto" data-user-id="602921" data-xf-init="member-tooltip">Max364</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-11-20T02:17:16-0600" data-time="1732090636" data-date-string="Nov 20, 2024" data-time-string="2:17 AM" title="Nov 20, 2024 at 2:17 AM">Nov 20, 2024</time></li> <li> <dl class="tagList tagList--thread-1067028 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/movement/" data-xf-init="preview-tooltip" data-preview-url="/tags/movement/preview" class="tagItem tagItem--tag_movement" dir="auto"> Movement </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="FranzS"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/franzs.684446/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="684446" data-xf-init="member-tooltip" style="background-color: #66cc99; color: #206040"> <span class="avatar-u684446-s" role="img" aria-label="FranzS">F</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/is-measuring-the-one-way-speed-of-light-possible-near-a-black-hole.1066767/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Is Measuring the One-Way Speed of Light Possible Near a Black Hole?</a> </h3> <div class="contentRow-snippet">Hi PF, as far as my modest knowledge goes, measuring the one-way speed of light is impossible / non-sensical (?). Thus I'm not here to actually propose a possible method for that purpose, but I just would like the savvy among you to point out the fallacy in my reasoning. That said, I was...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/franzs.684446/" class="username " dir="auto" data-user-id="684446" data-xf-init="member-tooltip">FranzS</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-11-06T18:01:40-0600" data-time="1730937700" data-date-string="Nov 6, 2024" data-time-string="6:01 PM" title="Nov 6, 2024 at 6:01 PM">Nov 6, 2024</time></li> <li> <dl class="tagList tagList--thread-1066767 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 10</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="benorin"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/benorin.37674/" class="avatar avatar--s" data-user-id="37674" data-xf-init="member-tooltip"> <img src="/data/avatars/s/37/37674.jpg?1584067974" srcset="/data/avatars/m/37/37674.jpg?1584067974 2x" alt="benorin" class="avatar-u37674-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/does-light-bend-around-black-holes.1066425/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Does light bend around black holes?</a> </h3> <div class="contentRow-snippet">Does light bend around black holes like a satellite "slingshotting" around Jupiter? If so, would there be a need to recalculate the true positions of stars from all the bending of light around black holes on the way to the telescope?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/benorin.37674/" class="username " dir="auto" data-user-id="37674" data-xf-init="member-tooltip">benorin</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-10-20T20:53:45-0500" data-time="1729475625" data-date-string="Oct 20, 2024" data-time-string="8:53 PM" title="Oct 20, 2024 at 8:53 PM">Oct 20, 2024</time></li> <li> <dl class="tagList tagList--thread-1066425 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/bend/" data-xf-init="preview-tooltip" data-preview-url="/tags/bend/preview" class="tagItem tagItem--tag_bend" dir="auto"> Bend </a> <a href="/tags/black-hole/" data-xf-init="preview-tooltip" data-preview-url="/tags/black-hole/preview" class="tagItem tagItem--tag_black-hole" dir="auto"> Black hole </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 49</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="zenterix"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/zenterix.695508/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="695508" data-xf-init="member-tooltip" style="background-color: #996633; color: #dfbf9f"> <span class="avatar-u695508-s" role="img" aria-label="zenterix">Z</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/what-does-it-mean-that-when-light-is-reflected-the-wavelengths-of-each-contributing-hue-are-subtracted.1066237/">What does it mean that when light is reflected the "wavelengths of each contributing hue are subtracted"?</a> </h3> <div class="contentRow-snippet">Each type of cell responds to light with wavelengths in a certain range. The distinct ranges center around yellowish red, green, and bluish violet, respectively. A "response" from a receptor cell is some neural signal to the brain. The combination of the responses of all our receptor cells...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/zenterix.695508/" class="username " dir="auto" data-user-id="695508" data-xf-init="member-tooltip">zenterix</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-10-11T15:54:35-0500" data-time="1728680075" data-date-string="Oct 11, 2024" data-time-string="3:54 PM" title="Oct 11, 2024 at 3:54 PM">Oct 11, 2024</time></li> <li> <dl class="tagList tagList--thread-1066237 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/color/" data-xf-init="preview-tooltip" data-preview-url="/tags/color/preview" class="tagItem tagItem--tag_color" dir="auto"> Color </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 16</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="latot"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/latot.687545/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="687545" data-xf-init="member-tooltip" style="background-color: #996666; color: #e0d1d1"> <span class="avatar-u687545-s" role="img" aria-label="latot">L</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/isolation-box-to-measure-light-source-inside-closer-to-visible-light.1065948/"><span class="prefix misc" dir="auto">Misc.</span><span class="label-append"> </span>Isolation box to measure light source inside (closer to visible light)</a> </h3> <div class="contentRow-snippet">Hi! (newbie here) I'm doing a experiment, very simple, in the center of a box there is a light source, a small one, and closer is a photon counter device. The challenge here, and the hard DIY part is the box. The box can not any photon get inside, nor emit any of them. At the same time it...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/latot.687545/" class="username " dir="auto" data-user-id="687545" data-xf-init="member-tooltip">latot</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-09-27T08:59:57-0500" data-time="1727445597" data-date-string="Sep 27, 2024" data-time-string="8:59 AM" title="Sep 27, 2024 at 8:59 AM">Sep 27, 2024</time></li> <li> <dl class="tagList tagList--thread-1065948 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/diy/" data-xf-init="preview-tooltip" data-preview-url="/tags/diy/preview" class="tagItem tagItem--tag_diy" dir="auto"> Diy </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/sensor/" data-xf-init="preview-tooltip" data-preview-url="/tags/sensor/preview" class="tagItem tagItem--tag_sensor" dir="auto"> Sensor </a> </span> </dd> </dl> </li> <li>Replies: 21</li> <li>Forum: <a href="/forums/diy-projects.264/">DIY Projects</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="LightPhoton"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/lightphoton.748212/" class="avatar avatar--s" data-user-id="748212" data-xf-init="member-tooltip"> <img src="/data/avatars/s/748/748212.jpg?1713781509" srcset="/data/avatars/m/748/748212.jpg?1713781509 2x" alt="LightPhoton" class="avatar-u748212-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/is-geometrical-optics-essential-for-a-deeper-understanding-of-light.1065847/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Is Geometrical Optics Essential for a Deeper Understanding of Light?</a> </h3> <div class="contentRow-snippet">Is Geometrical Optics (GO) essential to fully appreciate the nature of light? I absolutely love Wave Optics (WO) and am currently studying it at the undergraduate level. However, GO feels more like an applied science, where I’m mostly dealing with the geometry of small angles. It doesn’t give me...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/lightphoton.748212/" class="username " dir="auto" data-user-id="748212" data-xf-init="member-tooltip">LightPhoton</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-09-22T07:54:42-0500" data-time="1727009682" data-date-string="Sep 22, 2024" data-time-string="7:54 AM" title="Sep 22, 2024 at 7:54 AM">Sep 22, 2024</time></li> <li> <dl class="tagList tagList--thread-1065847 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/advice/" data-xf-init="preview-tooltip" data-preview-url="/tags/advice/preview" class="tagItem tagItem--tag_advice" dir="auto"> advice </a> <a href="/tags/geometrical-optics/" data-xf-init="preview-tooltip" data-preview-url="/tags/geometrical-optics/preview" class="tagItem tagItem--tag_geometrical-optics" dir="auto"> Geometrical optics </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/physics-education/" data-xf-init="preview-tooltip" data-preview-url="/tags/physics-education/preview" class="tagItem tagItem--tag_physics-education" dir="auto"> Physics education </a> <a href="/tags/wave-optics/" data-xf-init="preview-tooltip" data-preview-url="/tags/wave-optics/preview" class="tagItem tagItem--tag_wave-optics" dir="auto"> Wave optics </a> </span> </dd> </dl> </li> <li>Replies: 10</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="member 743765"> <div class="contentRow "> <span class="contentRow-figure"> <span class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="0" style="background-color: #66cc33; color: #1f3d0f" title="member 743765"> <span class="avatar-u0-s" role="img" aria-label="member 743765">M</span> </span> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/distance-between-two-light-pulses.1065433/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Distance between two light pulses</a> </h3> <div class="contentRow-snippet">If a source emits a light pulse then waited one second and sent another pulse does the distance between the two pulses remain constant ? If yes is that mean their relative speed is zero? But why when we use lorentz transformation their relative speeds gives us zero over zero but if they travel...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><span class="username " dir="auto" data-user-id="0">member 743765</span></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-09-02T04:56:24-0500" data-time="1725270984" data-date-string="Sep 2, 2024" data-time-string="4:56 AM" title="Sep 2, 2024 at 4:56 AM">Sep 2, 2024</time></li> <li> <dl class="tagList tagList--thread-1065433 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/distance/" data-xf-init="preview-tooltip" data-preview-url="/tags/distance/preview" class="tagItem tagItem--tag_distance" dir="auto"> distance </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/pulse/" data-xf-init="preview-tooltip" data-preview-url="/tags/pulse/preview" class="tagItem tagItem--tag_pulse" dir="auto"> Pulse </a> </span> </dd> </dl> </li> <li>Replies: 4</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="CB33"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/cb33.752044/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="752044" data-xf-init="member-tooltip" style="background-color: #6699cc; color: #204060"> <span class="avatar-u752044-s" role="img" aria-label="CB33">C</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/12v-dc-motor-in-light-fixture-with-dimmer-12v-dc-to-110v-ac-inverter.1065225/">12V DC Motor in Light Fixture with Dimmer & 12V DC to 110V AC Inverter</a> </h3> <div class="contentRow-snippet">I have a question regarding a light fixture I'm building that also has a motor in it. It has geometric shapes that spin slowly around the light (almost like a mobile) and this is what I'm using the motor for. The light fixture will be attached to the ceiling like any normal light fixture or...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/cb33.752044/" class="username " dir="auto" data-user-id="752044" data-xf-init="member-tooltip">CB33</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-08-21T16:06:23-0500" data-time="1724274383" data-date-string="Aug 21, 2024" data-time-string="4:06 PM" title="Aug 21, 2024 at 4:06 PM">Aug 21, 2024</time></li> <li> <dl class="tagList tagList--thread-1065225 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/switch/" data-xf-init="preview-tooltip" data-preview-url="/tags/switch/preview" class="tagItem tagItem--tag_switch" dir="auto"> Switch </a> </span> </dd> </dl> </li> <li>Replies: 21</li> <li>Forum: <a href="/forums/electrical-engineering.102/">Electrical Engineering</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Speady"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/speady.682013/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="682013" data-xf-init="member-tooltip" style="background-color: #5c99d6; color: #1a4066"> <span class="avatar-u682013-s" role="img" aria-label="Speady">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/speed-of-light-seen-by-a-moving-observer.1065185/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Speed of light seen by a moving observer</a> </h3> <div class="contentRow-snippet">How can the speed of light remain the same for an observer while the duration of a light beam is shorter if you move towards the light, and longer if you move with the light? The light beam remains the same length.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/speady.682013/" class="username " dir="auto" data-user-id="682013" data-xf-init="member-tooltip">Speady</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-08-20T04:04:27-0500" data-time="1724144667" data-date-string="Aug 20, 2024" data-time-string="4:04 AM" title="Aug 20, 2024 at 4:04 AM">Aug 20, 2024</time></li> <li> <dl class="tagList tagList--thread-1065185 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/observer/" data-xf-init="preview-tooltip" data-preview-url="/tags/observer/preview" class="tagItem tagItem--tag_observer" dir="auto"> Observer </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 24</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="walker35867"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/walker35867.751799/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="751799" data-xf-init="member-tooltip" style="background-color: #cc8f33; color: #3d2b0f"> <span class="avatar-u751799-s" role="img" aria-label="walker35867">W</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-does-the-heisenberg-uncertainty-principle-relate-to-electron-confinement.1065082/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>How Does the Heisenberg Uncertainty Principle Relate to Electron Confinement?</a> </h3> <div class="contentRow-snippet">https://physics.stackexchange.com/questions/824561/two-element-theory</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/walker35867.751799/" class="username " dir="auto" data-user-id="751799" data-xf-init="member-tooltip">walker35867</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-08-14T12:49:56-0500" data-time="1723657796" data-date-string="Aug 14, 2024" data-time-string="12:49 PM" title="Aug 14, 2024 at 12:49 PM">Aug 14, 2024</time></li> <li> <dl class="tagList tagList--thread-1065082 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/quantum/" data-xf-init="preview-tooltip" data-preview-url="/tags/quantum/preview" class="tagItem tagItem--tag_quantum" dir="auto"> Quantum </a> <a href="/tags/quantum-and-general-physics/" data-xf-init="preview-tooltip" data-preview-url="/tags/quantum-and-general-physics/preview" class="tagItem tagItem--tag_quantum-and-general-physics" dir="auto"> Quantum and general physics </a> <a href="/tags/quantum-machenics/" data-xf-init="preview-tooltip" data-preview-url="/tags/quantum-machenics/preview" class="tagItem tagItem--tag_quantum-machenics" dir="auto"> Quantum machenics </a> <a href="/tags/wave-particle-duality-2/" data-xf-init="preview-tooltip" data-preview-url="/tags/wave-particle-duality-2/preview" class="tagItem tagItem--tag_wave-particle-duality-2" dir="auto"> Wave-particle duality </a> </span> </dd> </dl> </li> <li>Replies: 16</li> <li>Forum: <a href="/forums/quantum-physics.62/">Quantum Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="jnhrtmn"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/jnhrtmn.750903/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="750903" data-xf-init="member-tooltip" style="background-color: #5cd65c; color: #1a661a"> <span class="avatar-u750903-s" role="img" aria-label="jnhrtmn">J</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-can-the-universe-know-when-you-change-directions.1064518/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>How can the Universe know when you change directions?</a> </h3> <div class="contentRow-snippet">If you and your frame are following a square path in space, and the Universe is the other frame, each leg of the square path instantly changes every photon in the Universe to suit your dimensional perspective of speed, length, frequency, and time. Is this new light situation actually different...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/jnhrtmn.750903/" class="username " dir="auto" data-user-id="750903" data-xf-init="member-tooltip">jnhrtmn</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-07-22T08:23:20-0500" data-time="1721654600" data-date-string="Jul 22, 2024" data-time-string="8:23 AM" title="Jul 22, 2024 at 8:23 AM">Jul 22, 2024</time></li> <li> <dl class="tagList tagList--thread-1064518 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/dimension/" data-xf-init="preview-tooltip" data-preview-url="/tags/dimension/preview" class="tagItem tagItem--tag_dimension" dir="auto"> Dimension </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/space/" data-xf-init="preview-tooltip" data-preview-url="/tags/space/preview" class="tagItem tagItem--tag_space" dir="auto"> Space </a> </span> </dd> </dl> </li> <li>Replies: 42</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Albertgauss"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/albertgauss.349172/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="349172" data-xf-init="member-tooltip" style="background-color: #66cc33; color: #1f3d0f"> <span class="avatar-u349172-s" role="img" aria-label="Albertgauss">A</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/for-a-relativistic-spaceship-what-is-the-most-recent-news-the-ship-gets-from-earth.1064291/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>For a relativistic spaceship, what is the most recent news the ship gets from Earth?</a> </h3> <div class="contentRow-snippet">Looking to see if I am in the ballpark correct about this. Let's say a spaceship flies at 99% the speed of light (B=0.99) to a planet 12 light years away. The spaceship is going to land on the planet once it arrives and stay put ever after. Ignore acceleration of start/stop. When it lands on the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/albertgauss.349172/" class="username " dir="auto" data-user-id="349172" data-xf-init="member-tooltip">Albertgauss</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-07-12T13:00:43-0500" data-time="1720807243" data-date-string="Jul 12, 2024" data-time-string="1:00 PM" title="Jul 12, 2024 at 1:00 PM">Jul 12, 2024</time></li> <li> <dl class="tagList tagList--thread-1064291 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/spaceship/" data-xf-init="preview-tooltip" data-preview-url="/tags/spaceship/preview" class="tagItem tagItem--tag_spaceship" dir="auto"> Spaceship </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 6</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Aryamehr"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/aryamehr.746885/" class="avatar avatar--s" data-user-id="746885" data-xf-init="member-tooltip"> <img src="/data/avatars/s/746/746885.jpg?1710836650" srcset="/data/avatars/m/746/746885.jpg?1710836650 2x" alt="Aryamehr" class="avatar-u746885-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/fluorescent-lamps-and-fan-remote.1064213/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Fluorescent lamps And Fan remote</a> </h3> <div class="contentRow-snippet">Hi everyone. I hope you are doing great . I recently saw something interesting and had a question. I use fluorescent lamps in my room, and when I use the remote fan, it works at a shorter distance, but when the lamps are off, the remote works at a longer distance. What do fluorescent lamps do...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/aryamehr.746885/" class="username " dir="auto" data-user-id="746885" data-xf-init="member-tooltip">Aryamehr</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-07-09T05:51:38-0500" data-time="1720522298" data-date-string="Jul 9, 2024" data-time-string="5:51 AM" title="Jul 9, 2024 at 5:51 AM">Jul 9, 2024</time></li> <li> <dl class="tagList tagList--thread-1064213 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/electromagnetic/" data-xf-init="preview-tooltip" data-preview-url="/tags/electromagnetic/preview" class="tagItem tagItem--tag_electromagnetic" dir="auto"> Electromagnetic </a> <a href="/tags/interference/" data-xf-init="preview-tooltip" data-preview-url="/tags/interference/preview" class="tagItem tagItem--tag_interference" dir="auto"> Interference </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 2</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="SamBiswas95"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/sambiswas95.750045/" class="avatar avatar--s" data-user-id="750045" data-xf-init="member-tooltip"> <img src="/data/avatars/s/750/750045.jpg?1718483613" srcset="/data/avatars/m/750/750045.jpg?1718483613 2x" alt="SamBiswas95" class="avatar-u750045-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/if-95-of-the-atmosphere-was-so2-how-would-the-sky-look.1063639/">If 95% of the atmosphere was SO2, how would the sky look?</a> </h3> <div class="contentRow-snippet">Taking into account the Rayleigh scattering phenomenon, assuming that the atmosphere is 1 bar, how would the light from the G2V-type star interact with this kind of environment? Could the colour of the sky even alter despite the fact that there is a significant amount of sulfur dioxide in the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/sambiswas95.750045/" class="username " dir="auto" data-user-id="750045" data-xf-init="member-tooltip">SamBiswas95</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-06-15T15:38:01-0500" data-time="1718483881" data-date-string="Jun 15, 2024" data-time-string="3:38 PM" title="Jun 15, 2024 at 3:38 PM">Jun 15, 2024</time></li> <li> <dl class="tagList tagList--thread-1063639 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/atmoshpere/" data-xf-init="preview-tooltip" data-preview-url="/tags/atmoshpere/preview" class="tagItem tagItem--tag_atmoshpere" dir="auto"> Atmoshpere </a> <a href="/tags/chemistry/" data-xf-init="preview-tooltip" data-preview-url="/tags/chemistry/preview" class="tagItem tagItem--tag_chemistry" dir="auto"> Chemistry </a> <a href="/tags/color/" data-xf-init="preview-tooltip" data-preview-url="/tags/color/preview" class="tagItem tagItem--tag_color" dir="auto"> Color </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 1</li> <li>Forum: <a href="/forums/new-member-introductions.240/">New Member Introductions</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="ESponge2000"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/esponge2000.749167/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="749167" data-xf-init="member-tooltip" style="background-color: #29a366; color: #05140d"> <span class="avatar-u749167-s" role="img" aria-label="ESponge2000">E</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/can-speed-of-light-distinguish-all-timelapse-videos-from-real-motion.1063441/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Can “speed of light” distinguish all Timelapse videos from real motion?</a> </h3> <div class="contentRow-snippet">my question then is that can we ascertain some unknowns about the physical constants of our universe by using video altered speeds , to observe the universe through moving picture frames ? Is there a project benefit in doing more with this ?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/esponge2000.749167/" class="username " dir="auto" data-user-id="749167" data-xf-init="member-tooltip">ESponge2000</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-06-08T21:18:11-0500" data-time="1717899491" data-date-string="Jun 8, 2024" data-time-string="9:18 PM" title="Jun 8, 2024 at 9:18 PM">Jun 8, 2024</time></li> <li> <dl class="tagList tagList--thread-1063441 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 14</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="ESponge2000"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/esponge2000.749167/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="749167" data-xf-init="member-tooltip" style="background-color: #29a366; color: #05140d"> <span class="avatar-u749167-s" role="img" aria-label="ESponge2000">E</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/proving-speed-of-light-constant-c-is-the-same-in-all-directions.1063229/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Proving speed of light constant “c” is the same in all directions?</a> </h3> <div class="contentRow-snippet">If I’m not mistaken, the synchronization of 2 clocks to conduct a measurement of the one-way speed of light is not possible since simultaneity is not possible and 2 clocks even if they are synchronized in a midpoint and slowly moved to opposite ends, depends on c being the same in all...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/esponge2000.749167/" class="username " dir="auto" data-user-id="749167" data-xf-init="member-tooltip">ESponge2000</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-06-01T10:13:08-0500" data-time="1717254788" data-date-string="Jun 1, 2024" data-time-string="10:13 AM" title="Jun 1, 2024 at 10:13 AM">Jun 1, 2024</time></li> <li> <dl class="tagList tagList--thread-1063229 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/constant/" data-xf-init="preview-tooltip" data-preview-url="/tags/constant/preview" class="tagItem tagItem--tag_constant" dir="auto"> Constant </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="hjgfx697"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/hjgfx697.749513/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="749513" data-xf-init="member-tooltip" style="background-color: #3366cc; color: #c2d1f0"> <span class="avatar-u749513-s" role="img" aria-label="hjgfx697">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/are-some-objects-in-the-night-sky-just-older-images-of-other-objects.1063154/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Are some objects in the night sky just older images of other objects?</a> </h3> <div class="contentRow-snippet">It's a question I've pondered over for years and I've even asked a few people but I've never had a convincing answer. As per the summary, if gravitational lensing is spraying light all over the place like an automatic lawn irrigator, is there any chance some light will do a tour of the universe...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/hjgfx697.749513/" class="username " dir="auto" data-user-id="749513" data-xf-init="member-tooltip">hjgfx697</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-29T10:48:36-0500" data-time="1716997716" data-date-string="May 29, 2024" data-time-string="10:48 AM" title="May 29, 2024 at 10:48 AM">May 29, 2024</time></li> <li> <dl class="tagList tagList--thread-1063154 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/gravitational/" data-xf-init="preview-tooltip" data-preview-url="/tags/gravitational/preview" class="tagItem tagItem--tag_gravitational" dir="auto"> Gravitational </a> <a href="/tags/lensing/" data-xf-init="preview-tooltip" data-preview-url="/tags/lensing/preview" class="tagItem tagItem--tag_lensing" dir="auto"> Lensing </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 12</li> <li>Forum: <a href="/forums/astronomy-and-astrophysics.71/">Astronomy and Astrophysics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="gnnmartin"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/gnnmartin.31668/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="31668" data-xf-init="member-tooltip" style="background-color: #cc6699; color: #602040"> <span class="avatar-u31668-s" role="img" aria-label="gnnmartin">G</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/i-want-a-good-reference-to-a-discussion-of-the-meaning-of-the-speed-of-light-is-constant.1063110/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>I want a good reference to a discussion of the meaning of "the speed of light is constant"</a> </h3> <div class="contentRow-snippet">I am interested in making an observation that involves the speed of light. It is widely stated that the speed of light is constant, but without saying what that means. I need to be precise, and would like a reference to an acknowledgement of the problem. When people talk about the speed of...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/gnnmartin.31668/" class="username " dir="auto" data-user-id="31668" data-xf-init="member-tooltip">gnnmartin</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-28T07:02:26-0500" data-time="1716897746" data-date-string="May 28, 2024" data-time-string="7:02 AM" title="May 28, 2024 at 7:02 AM">May 28, 2024</time></li> <li> <dl class="tagList tagList--thread-1063110 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/discussion/" data-xf-init="preview-tooltip" data-preview-url="/tags/discussion/preview" class="tagItem tagItem--tag_discussion" dir="auto"> Discussion </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 60</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="difalcojr"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/difalcojr.737933/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="737933" data-xf-init="member-tooltip" style="background-color: #a32966; color: #e699bf"> <span class="avatar-u737933-s" role="img" aria-label="difalcojr">D</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/mt-vesuvius-1944-eruption-light-show-static-electricity.1062809/">Mt. Vesuvius 1944 eruption light show -- Static electricity?</a> </h3> <div class="contentRow-snippet">The caption says this volcanic 'light show' was caused from "an accumulation of static electricity". If that is so, I do not know the physical reason for that at all. Hopefully, someone can enlighten the ignorant. If it is something other than that, possibly, my guess would be that...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/difalcojr.737933/" class="username " dir="auto" data-user-id="737933" data-xf-init="member-tooltip">difalcojr</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-18T14:44:25-0500" data-time="1716061465" data-date-string="May 18, 2024" data-time-string="2:44 PM" title="May 18, 2024 at 2:44 PM">May 18, 2024</time></li> <li> <dl class="tagList tagList--thread-1062809 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/volcano/" data-xf-init="preview-tooltip" data-preview-url="/tags/volcano/preview" class="tagItem tagItem--tag_volcano" dir="auto"> Volcano </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/earth-sciences.84/">Earth Sciences</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="LarryS"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/larrys.154174/" class="avatar avatar--s" data-user-id="154174" data-xf-init="member-tooltip"> <img src="/data/avatars/s/154/154174.jpg?1431189819" alt="LarryS" class="avatar-u154174-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/plancks-constant-times-the-speed-of-light.1062694/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Planck's Constant times the speed of light</a> </h3> <div class="contentRow-snippet">Does the product of Planck's Constant and the speed of light, hc, have any significance in physics other than an arbitrary product of two constants? I noticed that it appears in one formula for the fine structure constant. It also appears in Planck's formula for black body radiation. Thanks...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/larrys.154174/" class="username " dir="auto" data-user-id="154174" data-xf-init="member-tooltip">LarryS</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-13T19:54:42-0500" data-time="1715648082" data-date-string="May 13, 2024" data-time-string="7:54 PM" title="May 13, 2024 at 7:54 PM">May 13, 2024</time></li> <li> <dl class="tagList tagList--thread-1062694 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/planck/" data-xf-init="preview-tooltip" data-preview-url="/tags/planck/preview" class="tagItem tagItem--tag_planck" dir="auto"> Planck </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 11</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="thetexan"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/thetexan.296810/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="296810" data-xf-init="member-tooltip" style="background-color: #521433; color: #d1478c"> <span class="avatar-u296810-s" role="img" aria-label="thetexan">T</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/why-186-282.1062623/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Why 186,282?</a> </h3> <div class="contentRow-snippet">Is there an explanation for why the speed of light tops out at 186,282 miles per second? Of course that number depends on our definition of miles and seconds. If a mile was 3000 feet then c would be a different number. But whatever speed it is…. Why that speed? In other words… there is...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/thetexan.296810/" class="username " dir="auto" data-user-id="296810" data-xf-init="member-tooltip">thetexan</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-10T23:26:45-0500" data-time="1715401605" data-date-string="May 10, 2024" data-time-string="11:26 PM" title="May 10, 2024 at 11:26 PM">May 10, 2024</time></li> <li> <dl class="tagList tagList--thread-1062623 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/limit/" data-xf-init="preview-tooltip" data-preview-url="/tags/limit/preview" class="tagItem tagItem--tag_limit" dir="auto"> Limit </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 120</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="dbecker"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/dbecker.748851/" class="avatar avatar--s" data-user-id="748851" data-xf-init="member-tooltip"> <img src="https://secure.gravatar.com/avatar/398176bd95f86d7a38b627c40f154c0f?s=48" srcset="https://secure.gravatar.com/avatar/398176bd95f86d7a38b627c40f154c0f?s=96 2x" alt="dbecker" class="avatar-u748851-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/static-electricity-like-tree-lightning-on-my-ceiling.1062553/">Static electricity (like tree lightning) on my ceiling?</a> </h3> <div class="contentRow-snippet">I had a rough night of sleep tonight and woke about 3:30. At one point I was awake on my side and noticed a small burst of light in the room, which I found a bit odd, being familiar with all the things that blink, etc., and not expecting any. But I figured it was just one of those. Then, about...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/dbecker.748851/" class="username " dir="auto" data-user-id="748851" data-xf-init="member-tooltip">dbecker</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-09T04:49:12-0500" data-time="1715248152" data-date-string="May 9, 2024" data-time-string="4:49 AM" title="May 9, 2024 at 4:49 AM">May 9, 2024</time></li> <li> <dl class="tagList tagList--thread-1062553 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/electromagetism/" data-xf-init="preview-tooltip" data-preview-url="/tags/electromagetism/preview" class="tagItem tagItem--tag_electromagetism" dir="auto"> Electromagetism </a> <a href="/tags/flash/" data-xf-init="preview-tooltip" data-preview-url="/tags/flash/preview" class="tagItem tagItem--tag_flash" dir="auto"> Flash </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/strange/" data-xf-init="preview-tooltip" data-preview-url="/tags/strange/preview" class="tagItem tagItem--tag_strange" dir="auto"> Strange </a> </span> </dd> </dl> </li> <li>Replies: 24</li> <li>Forum: <a href="/forums/general-discussion.14/">General Discussion</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="felizgu"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/felizgu.748577/" class="avatar avatar--s" data-user-id="748577" data-xf-init="member-tooltip"> <img src="/data/avatars/s/748/748577.jpg?1714611279" srcset="/data/avatars/m/748/748577.jpg?1714611279 2x" alt="felizgu" class="avatar-u748577-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-long-for-a-beam-of-light-to-reach-earth.1062322/">How Long for a Beam of Light to Reach Earth?</a> </h3> <div class="contentRow-snippet">TL;DR Summary: This is an astronomy application. Mentor note: Moved from a technical forum section, so the homework template is missing. How long does it take a beam of light to reach Earth from the Sun when the Sun is 93,000,000 miles from Earth? Express your answer in seconds, using...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/felizgu.748577/" class="username " dir="auto" data-user-id="748577" data-xf-init="member-tooltip">felizgu</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-05-01T21:26:01-0500" data-time="1714616761" data-date-string="May 1, 2024" data-time-string="9:26 PM" title="May 1, 2024 at 9:26 PM">May 1, 2024</time></li> <li> <dl class="tagList tagList--thread-1062322 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/earth/" data-xf-init="preview-tooltip" data-preview-url="/tags/earth/preview" class="tagItem tagItem--tag_earth" dir="auto"> Earth </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 21</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Harry Logtenberg"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/harry-logtenberg.748140/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="748140" data-xf-init="member-tooltip" style="background-color: #999966; color: #2e2e1f"> <span class="avatar-u748140-s" role="img" aria-label="Harry Logtenberg">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/designing-reflector-straight-line-lamp.1061983/">Designing reflector straight line lamp</a> </h3> <div class="contentRow-snippet">Who can help me to calculated a reflector for a straight light tube with a diameter of 6mm and a length of 300mm given a beam with a width of 100mm at a distance of 500-700mm?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/harry-logtenberg.748140/" class="username " dir="auto" data-user-id="748140" data-xf-init="member-tooltip">Harry Logtenberg</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-20T04:04:46-0500" data-time="1713603886" data-date-string="Apr 20, 2024" data-time-string="4:04 AM" title="Apr 20, 2024 at 4:04 AM">Apr 20, 2024</time></li> <li> <dl class="tagList tagList--thread-1061983 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/reflector/" data-xf-init="preview-tooltip" data-preview-url="/tags/reflector/preview" class="tagItem tagItem--tag_reflector" dir="auto"> Reflector </a> <a href="/tags/tube/" data-xf-init="preview-tooltip" data-preview-url="/tags/tube/preview" class="tagItem tagItem--tag_tube" dir="auto"> Tube </a> </span> </dd> </dl> </li> <li>Replies: 3</li> <li>Forum: <a href="/forums/precalculus-mathematics-homework-help.155/">Precalculus Mathematics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="kelly0303"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/kelly0303.650912/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="650912" data-xf-init="member-tooltip" style="background-color: #7a1f5c; color: #db70b8"> <span class="avatar-u650912-s" role="img" aria-label="kelly0303">K</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/function-to-fit-the-light-transmitted-from-a-cavity.1061916/"><span class="prefix advanced" dir="auto">A</span><span class="label-append"> </span>Function to fit the light transmitted from a cavity</a> </h3> <div class="contentRow-snippet">Hello! I measured the light transmitted from a bow-tie cavity (while scanning the cavity length) and the peak obtained while scanning has the shape in the figure below. It is basically a combination of a Lorentzian, with an exponential decay on the right side and some oscillations on top. What...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/kelly0303.650912/" class="username " dir="auto" data-user-id="650912" data-xf-init="member-tooltip">kelly0303</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-17T15:53:23-0500" data-time="1713387203" data-date-string="Apr 17, 2024" data-time-string="3:53 PM" title="Apr 17, 2024 at 3:53 PM">Apr 17, 2024</time></li> <li> <dl class="tagList tagList--thread-1061916 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/fit/" data-xf-init="preview-tooltip" data-preview-url="/tags/fit/preview" class="tagItem tagItem--tag_fit" dir="auto"> Fit </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 1</li> <li>Forum: <a href="/forums/atomic-and-condensed-matter.64/">Atomic and Condensed Matter</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Herbascious J"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/herbascious-j.132281/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="132281" data-xf-init="member-tooltip" style="background-color: #7a1f3d; color: #db7094"> <span class="avatar-u132281-s" role="img" aria-label="Herbascious J">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/do-observers-always-agree-on-the-number-of-waves-in-a-beam-of-light.1061798/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Do observers always agree on the number of waves in a beam of light?</a> </h3> <div class="contentRow-snippet">Imagine there is an experiment setup on a train. A laser, with a specific wavelength of light, is aimed at a target. The target is at a distance from the laser of some multiple of the wavelength. Let's say 10cm for the target distance, and the light's wavelength is 1cm, so when a pulse of...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/herbascious-j.132281/" class="username " dir="auto" data-user-id="132281" data-xf-init="member-tooltip">Herbascious J</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-14T02:51:01-0500" data-time="1713081061" data-date-string="Apr 14, 2024" data-time-string="2:51 AM" title="Apr 14, 2024 at 2:51 AM">Apr 14, 2024</time></li> <li> <dl class="tagList tagList--thread-1061798 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/waves/" data-xf-init="preview-tooltip" data-preview-url="/tags/waves/preview" class="tagItem tagItem--tag_waves" dir="auto"> Waves </a> </span> </dd> </dl> </li> <li>Replies: 12</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="greypilgrim"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/greypilgrim.490763/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="490763" data-xf-init="member-tooltip" style="background-color: #c2c2f0; color: #3333cc"> <span class="avatar-u490763-s" role="img" aria-label="greypilgrim">G</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/does-the-speed-of-light-pop-out-of-other-theories-than-em.1061642/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Does the speed of light pop out of other theories than EM?</a> </h3> <div class="contentRow-snippet">Hi. The numerical value of the speed of light ##c## pops out as propagation speed of the wave solutions to Maxwell's equations. It seems like everywhere else we need to plug in ##c## as a parameter. Why is that? Is there a way to "derive" the numerical value of ##c## in other theories, that...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/greypilgrim.490763/" class="username " dir="auto" data-user-id="490763" data-xf-init="member-tooltip">greypilgrim</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-09T05:32:07-0500" data-time="1712658727" data-date-string="Apr 9, 2024" data-time-string="5:32 AM" title="Apr 9, 2024 at 5:32 AM">Apr 9, 2024</time></li> <li> <dl class="tagList tagList--thread-1061642 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> <a href="/tags/theories/" data-xf-init="preview-tooltip" data-preview-url="/tags/theories/preview" class="tagItem tagItem--tag_theories" dir="auto"> Theories </a> </span> </dd> </dl> </li> <li>Replies: 16</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Maximum7"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/maximum7.664146/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="664146" data-xf-init="member-tooltip" style="background-color: #d4c4c4; color: #846262"> <span class="avatar-u664146-s" role="img" aria-label="Maximum7">M</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/can-objects-in-nature-store-light-information-on-the-quantum-level.1061569/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Can objects in nature store light information on the quantum level?</a> </h3> <div class="contentRow-snippet">In the 1934 novel by John Taine, Before the Dawn, scientists are able to retrieve images of the past by accessing the light absorbed by stones throughout history. While this is fictional, 1934 was really before the dawn of quantum physics. In the far future, could we retrieve images from light...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/maximum7.664146/" class="username " dir="auto" data-user-id="664146" data-xf-init="member-tooltip">Maximum7</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-06T16:10:30-0500" data-time="1712437830" data-date-string="Apr 6, 2024" data-time-string="4:10 PM" title="Apr 6, 2024 at 4:10 PM">Apr 6, 2024</time></li> <li> <dl class="tagList tagList--thread-1061569 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/future-technology/" data-xf-init="preview-tooltip" data-preview-url="/tags/future-technology/preview" class="tagItem tagItem--tag_future-technology" dir="auto"> Future technology </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/light-absorbtion/" data-xf-init="preview-tooltip" data-preview-url="/tags/light-absorbtion/preview" class="tagItem tagItem--tag_light-absorbtion" dir="auto"> <em class="textHighlight">Light</em> absorbtion </a> <a href="/tags/quantum/" data-xf-init="preview-tooltip" data-preview-url="/tags/quantum/preview" class="tagItem tagItem--tag_quantum" dir="auto"> Quantum </a> <a href="/tags/quantum-phyics/" data-xf-init="preview-tooltip" data-preview-url="/tags/quantum-phyics/preview" class="tagItem tagItem--tag_quantum-phyics" dir="auto"> Quantum phyics </a> </span> </dd> </dl> </li> <li>Replies: 14</li> <li>Forum: <a href="/forums/quantum-physics.62/">Quantum Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Swamp Thing"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/swamp-thing.5126/" class="avatar avatar--s" data-user-id="5126" data-xf-init="member-tooltip"> <img src="/data/avatars/s/5/5126.jpg?1738200575" srcset="/data/avatars/m/5/5126.jpg?1738200575 2x" alt="Swamp Thing" class="avatar-u5126-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/electron-counterpart-of-pseudothermal-light-source-for-quantum-experiments.1061488/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Electron counterpart of pseudothermal light source for quantum experiments</a> </h3> <div class="contentRow-snippet">Kuusela https://research.utu.fi/converis/portal/detail/Publication/32053938?lang=en_GB (published in AJP) (PDF here) describes a pseudothermal light source that can be built easily in college labs, and can be used to do some quantum correlation experiments. They propose this as an alternative...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/swamp-thing.5126/" class="username " dir="auto" data-user-id="5126" data-xf-init="member-tooltip">Swamp Thing</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-03T21:53:55-0500" data-time="1712199235" data-date-string="Apr 3, 2024" data-time-string="9:53 PM" title="Apr 3, 2024 at 9:53 PM">Apr 3, 2024</time></li> <li> <dl class="tagList tagList--thread-1061488 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/electron/" data-xf-init="preview-tooltip" data-preview-url="/tags/electron/preview" class="tagItem tagItem--tag_electron" dir="auto"> Electron </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 0</li> <li>Forum: <a href="/forums/quantum-physics.62/">Quantum Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="songoku"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/songoku.171861/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="171861" data-xf-init="member-tooltip" style="background-color: #6666cc; color: #ececf9"> <span class="avatar-u171861-s" role="img" aria-label="songoku">S</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/refraction-of-light-when-traveling-from-air-to-glass.1061461/">Refraction of light when traveling from air to glass</a> </h3> <div class="contentRow-snippet">I don't know how to explain it in terms of speed. I know the speed will decrease but if the ray entering the glass at certain angle, let say 10 degrees, the speed will also decrease so what is the relation of speed to the fact that the light will bend or not when entering the glass? And the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/songoku.171861/" class="username " dir="auto" data-user-id="171861" data-xf-init="member-tooltip">songoku</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-04-02T20:20:44-0500" data-time="1712107244" data-date-string="Apr 2, 2024" data-time-string="8:20 PM" title="Apr 2, 2024 at 8:20 PM">Apr 2, 2024</time></li> <li> <dl class="tagList tagList--thread-1061461 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/refraction/" data-xf-init="preview-tooltip" data-preview-url="/tags/refraction/preview" class="tagItem tagItem--tag_refraction" dir="auto"> Refraction </a> <a href="/tags/speed/" data-xf-init="preview-tooltip" data-preview-url="/tags/speed/preview" class="tagItem tagItem--tag_speed" dir="auto"> Speed </a> </span> </dd> </dl> </li> <li>Replies: 6</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="AI_Messiah"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/ai_messiah.698682/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="698682" data-xf-init="member-tooltip" style="background-color: #99cc33; color: #2e3d0f"> <span class="avatar-u698682-s" role="img" aria-label="AI_Messiah">A</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-would-someone-see-light-from-something-like-a-flashlight-in-a-tunnel.1061359/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>How would someone see light from something like a flashlight in a tunnel?</a> </h3> <div class="contentRow-snippet">What I mean is that how would someone see light from something like a flashlight in a tunnel? The idea of light rebounding like a ball against a wall I do understand. What I would like to apply this to is graphics programming. the objects that I would simulate this for are puddles on the floor...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/ai_messiah.698682/" class="username " dir="auto" data-user-id="698682" data-xf-init="member-tooltip">AI_Messiah</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-03-30T17:58:26-0500" data-time="1711839506" data-date-string="Mar 30, 2024" data-time-string="5:58 PM" title="Mar 30, 2024 at 5:58 PM">Mar 30, 2024</time></li> <li> <dl class="tagList tagList--thread-1061359 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/reflection/" data-xf-init="preview-tooltip" data-preview-url="/tags/reflection/preview" class="tagItem tagItem--tag_reflection" dir="auto"> Reflection </a> </span> </dd> </dl> </li> <li>Replies: 6</li> <li>Forum: <a href="/forums/optics.300/">Optics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="fro2g"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/fro2g.746881/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="746881" data-xf-init="member-tooltip" style="background-color: #3366cc; color: #c2d1f0"> <span class="avatar-u746881-s" role="img" aria-label="fro2g">F</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/why-does-my-ceiling-glow-in-the-dark.1061034/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Why does my ceiling glow in the dark?</a> </h3> <div class="contentRow-snippet">Can you explain this for my grandmother? Four years ago I rented an apartment for her on the 7th floor in a new building. I then decided to take care of my grandmother, so I lived with her. Everything was fine, but a year later the light bulb in the guest bathroom burned out. Since I'm the...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/fro2g.746881/" class="username " dir="auto" data-user-id="746881" data-xf-init="member-tooltip">fro2g</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-03-19T11:48:09-0500" data-time="1710866889" data-date-string="Mar 19, 2024" data-time-string="11:48 AM" title="Mar 19, 2024 at 11:48 AM">Mar 19, 2024</time></li> <li> <dl class="tagList tagList--thread-1061034 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 12</li> <li>Forum: <a href="/forums/other-physics-topics.111/">Other Physics Topics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="tagehedin"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/tagehedin.746667/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="746667" data-xf-init="member-tooltip" style="background-color: #5cd699; color: #1a6640"> <span class="avatar-u746667-s" role="img" aria-label="tagehedin">T</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/light-clock-running-faster-than-light.1060867/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Light clock running faster than light?</a> </h3> <div class="contentRow-snippet">Twin Paradox. I am on the outgoing rocket and look back at my stay at home twins light clock (two mirrors with a ray of light bouncing in between) I get to the nearest star and on the outbound journey my twins clock apears to run slow. When I turn around my plane of simultaneity shift and I...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/tagehedin.746667/" class="username " dir="auto" data-user-id="746667" data-xf-init="member-tooltip">tagehedin</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-03-13T12:38:27-0500" data-time="1710351507" data-date-string="Mar 13, 2024" data-time-string="12:38 PM" title="Mar 13, 2024 at 12:38 PM">Mar 13, 2024</time></li> <li> <dl class="tagList tagList--thread-1060867 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/clock/" data-xf-init="preview-tooltip" data-preview-url="/tags/clock/preview" class="tagItem tagItem--tag_clock" dir="auto"> Clock </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 4</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="elou"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/elou.746130/" class="avatar avatar--s" data-user-id="746130" data-xf-init="member-tooltip"> <img src="/data/avatars/s/746/746130.jpg?1709189304" srcset="/data/avatars/m/746/746130.jpg?1709189304 2x" alt="elou" class="avatar-u746130-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/light-beams-and-their-reflection.1060512/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Light beams and their reflection</a> </h3> <div class="contentRow-snippet">I must add, that, when used in a lit space, or in daylight, spraying before the mirror does not make any light rays visible. Is it simply a matter of light scattering? Also, I am not sure whether this question belongs here or in classical physics.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/elou.746130/" class="username " dir="auto" data-user-id="746130" data-xf-init="member-tooltip">elou</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-03-02T15:41:52-0600" data-time="1709415712" data-date-string="Mar 2, 2024" data-time-string="3:41 PM" title="Mar 2, 2024 at 3:41 PM">Mar 2, 2024</time></li> <li> <dl class="tagList tagList--thread-1060512 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/mirrors/" data-xf-init="preview-tooltip" data-preview-url="/tags/mirrors/preview" class="tagItem tagItem--tag_mirrors" dir="auto"> Mirrors </a> <a href="/tags/reflection/" data-xf-init="preview-tooltip" data-preview-url="/tags/reflection/preview" class="tagItem tagItem--tag_reflection" dir="auto"> Reflection </a> </span> </dd> </dl> </li> <li>Replies: 64</li> <li>Forum: <a href="/forums/optics.300/">Optics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Danielk010"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/danielk010.745977/" class="avatar avatar--s" data-user-id="745977" data-xf-init="member-tooltip"> <img src="/data/avatars/s/745/745977.jpg?1708887498" srcset="/data/avatars/m/745/745977.jpg?1708887498 2x" alt="Danielk010" class="avatar-u745977-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/how-does-one-calculate-the-number-of-photons-striking-a-surface-per-second.1060331/">How does one calculate the number of photons striking a surface per second?</a> </h3> <div class="contentRow-snippet">I am more so stuck on where to start with this problem. I know dividing the photons per second by the area gets me the photon per area, but I am not sure how the distance is related to this part of the problem. If anyone can help, thank you.</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/danielk010.745977/" class="username " dir="auto" data-user-id="745977" data-xf-init="member-tooltip">Danielk010</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-02-25T13:32:54-0600" data-time="1708889574" data-date-string="Feb 25, 2024" data-time-string="1:32 PM" title="Feb 25, 2024 at 1:32 PM">Feb 25, 2024</time></li> <li> <dl class="tagList tagList--thread-1060331 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/photon/" data-xf-init="preview-tooltip" data-preview-url="/tags/photon/preview" class="tagItem tagItem--tag_photon" dir="auto"> Photon </a> <a href="/tags/planck/" data-xf-init="preview-tooltip" data-preview-url="/tags/planck/preview" class="tagItem tagItem--tag_planck" dir="auto"> Planck </a> <a href="/tags/waves/" data-xf-init="preview-tooltip" data-preview-url="/tags/waves/preview" class="tagItem tagItem--tag_waves" dir="auto"> Waves </a> <a href="/tags/waves-and-light/" data-xf-init="preview-tooltip" data-preview-url="/tags/waves-and-light/preview" class="tagItem tagItem--tag_waves-and-light" dir="auto"> Waves and <em class="textHighlight">light</em> </a> </span> </dd> </dl> </li> <li>Replies: 12</li> <li>Forum: <a href="/forums/introductory-physics-homework-help.153/">Introductory Physics Homework Help</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="BiGyElLoWhAt"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/bigyellowhat.496972/" class="avatar avatar--s" data-user-id="496972" data-xf-init="member-tooltip"> <img src="/data/avatars/s/496/496972.jpg?1435697608" srcset="/data/avatars/m/496/496972.jpg?1435697608 2x" alt="BiGyElLoWhAt" class="avatar-u496972-s" width="48" height="48" loading="lazy" /> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/newtonian-path-of-light-in-a-gravitational-field.1060227/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Newtonian path of light in a gravitational field</a> </h3> <div class="contentRow-snippet">I think this is the appropriate subforum. I'm curious as to what approaches have been taken. I know this prediction isn't correct. I can think of at least a couple ways that I could go about this. They may or may not give the same prediction. One approach would be to simply use kinematics, and...</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/bigyellowhat.496972/" class="username " dir="auto" data-user-id="496972" data-xf-init="member-tooltip">BiGyElLoWhAt</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-02-22T15:48:27-0600" data-time="1708638507" data-date-string="Feb 22, 2024" data-time-string="3:48 PM" title="Feb 22, 2024 at 3:48 PM">Feb 22, 2024</time></li> <li> <dl class="tagList tagList--thread-1060227 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/gravitational/" data-xf-init="preview-tooltip" data-preview-url="/tags/gravitational/preview" class="tagItem tagItem--tag_gravitational" dir="auto"> Gravitational </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> <a href="/tags/newtonian/" data-xf-init="preview-tooltip" data-preview-url="/tags/newtonian/preview" class="tagItem tagItem--tag_newtonian" dir="auto"> Newtonian </a> </span> </dd> </dl> </li> <li>Replies: 8</li> <li>Forum: <a href="/forums/mechanics.299/">Mechanics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="abrahamabraham"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/abrahamabraham.745581/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="745581" data-xf-init="member-tooltip" style="background-color: #cccc99; color: #77773c"> <span class="avatar-u745581-s" role="img" aria-label="abrahamabraham">A</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/why-does-light-diffraction-create-circular-patterns.1060077/"><span class="prefix basic" dir="auto">B</span><span class="label-append"> </span>Why does light diffraction create circular patterns?</a> </h3> <div class="contentRow-snippet">We see under trees circular light that goes from sun through the leaves gaps. Why does it create a circular shape and not other shapes? why does this diffraction phenomenon create it in circular patterns?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/abrahamabraham.745581/" class="username " dir="auto" data-user-id="745581" data-xf-init="member-tooltip">abrahamabraham</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-02-16T09:11:17-0600" data-time="1708096277" data-date-string="Feb 16, 2024" data-time-string="9:11 AM" title="Feb 16, 2024 at 9:11 AM">Feb 16, 2024</time></li> <li> <dl class="tagList tagList--thread-1060077 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/circular/" data-xf-init="preview-tooltip" data-preview-url="/tags/circular/preview" class="tagItem tagItem--tag_circular" dir="auto"> Circular </a> <a href="/tags/diffraction/" data-xf-init="preview-tooltip" data-preview-url="/tags/diffraction/preview" class="tagItem tagItem--tag_diffraction" dir="auto"> Diffraction </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 5</li> <li>Forum: <a href="/forums/classical-physics.61/">Classical Physics</a></li> </ul> </div> </div> </div> </li> <li class="block-row block-row--separated js-inlineModContainer" data-author="Hill"> <div class="contentRow "> <span class="contentRow-figure"> <a href="/members/hill.738741/" class="avatar avatar--s avatar--default avatar--default--dynamic" data-user-id="738741" data-xf-init="member-tooltip" style="background-color: #d67a5c; color: #662d1a"> <span class="avatar-u738741-s" role="img" aria-label="Hill">H</span> </a> </span> <div class="contentRow-main"> <h3 class="contentRow-title"> <a href="/threads/seeing-history-when-crossing-event-horizon.1059970/"><span class="prefix inter" dir="auto">I</span><span class="label-append"> </span>Seeing history when crossing event horizon</a> </h3> <div class="contentRow-snippet">Looking at Kruskal diagram, it appears that light from all previous events of something crossing event horizon at that same point, reaches the falling observer when it crosses the event horizon. Is my interpretation correct?</div> <div class="contentRow-minor contentRow-minor--hideLinks"> <ul class="listInline listInline--bullet"> <li><a href="/members/hill.738741/" class="username " dir="auto" data-user-id="738741" data-xf-init="member-tooltip">Hill</a></li> <li>Thread</li> <li><time class="u-dt" dir="auto" datetime="2024-02-13T05:40:15-0600" data-time="1707824415" data-date-string="Feb 13, 2024" data-time-string="5:40 AM" title="Feb 13, 2024 at 5:40 AM">Feb 13, 2024</time></li> <li> <dl class="tagList tagList--thread-1059970 contentRow-minor"> <dt> <i class="fa--xf fal fa-tags" aria-hidden="true" title="Tags"></i> <span class="u-srOnly">Tags</span> </dt> <dd> <span class="js-tagList"> <a href="/tags/event-horizon/" data-xf-init="preview-tooltip" data-preview-url="/tags/event-horizon/preview" class="tagItem tagItem--tag_event-horizon" dir="auto"> Event horizon </a> <a href="/tags/light/" data-xf-init="preview-tooltip" data-preview-url="/tags/light/preview" class="tagItem tagItem--tag_light" dir="auto"> <em class="textHighlight">Light</em> </a> </span> </dd> </dl> </li> <li>Replies: 41</li> <li>Forum: <a href="/forums/special-and-general-relativity.70/">Special and General Relativity</a></li> </ul> </div> </div> </div> </li> </ol> </div> <div class="block-outer block-outer--after"> <div class="block-outer-main"> <nav class="pageNavWrapper pageNavWrapper--logarithmic pageNavWrapper--full " data-block-size="3" data-last-page="20"> <div class="pageNav"> <ul class="pageNav-main"> <li class="pageNav-page pageNav-page--current "><a href="/tags/light/">1</a></li> <li class="pageNav-page "><a href="/tags/light/page-2">2</a></li> <li class="pageNav-page "><a href="/tags/light/page-3">3</a></li> <li class="pageNav-page "><a href="/tags/light/page-4">4</a></li> <li class="pageNav-page "><a href="/tags/light/page-7">7</a></li> <li class="pageNav-page "><a href="/tags/light/page-10">10</a></li> <li class="pageNav-page "><a href="/tags/light/page-13">13</a></li> <li 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