https://www.explainxkcd.com/wiki/index.php?action=history&feed=atom&title=1125%3A_Objects_In_Mirror 2026-05-23T01:54:21Z Revision history for this page on the wiki MediaWiki 1.30.0 https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=361563&oldid=prev 2025-01-10T05:46:42Z

<p>‎<span dir="auto"><span class="autocomment">Explanation</span></span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 05:46, 10 January 2025</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l10" >Line 10:</td> <td colspan="2" class="diff-lineno">Line 10:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>&quot;Objects in mirror are closer than they appear&quot; is a required, although marginally ridiculous, &quot;safety warning&quot; required to be engraved on passenger side mirrors of motor vehicles in the USA, Canada and Korea. These mirrors in these countries are typically the only ones that are slightly convex, making objects appear smaller (and farther away) than their true size. Other countries often have convexity in driver-side and passenger-side rearview mirrors to give a larger field of view, at the cost of natural distance proportions of the mirror image, without making any statements about it on the mirror itself using engravings.</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>&quot;Objects in mirror are closer than they appear&quot; is a required, although marginally ridiculous, &quot;safety warning&quot; required to be engraved on passenger side mirrors of motor vehicles in the USA, Canada and Korea. These mirrors in these countries are typically the only ones that are slightly convex, making objects appear smaller (and farther away) than their true size. Other countries often have convexity in driver-side and passenger-side rearview mirrors to give a larger field of view, at the cost of natural distance proportions of the mirror image, without making any statements about it on the mirror itself using engravings.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>This comic is a reference to the <del class="diffchange diffchange-inline">phenomena </del>known as {{w|redshift}}/{{w|blueshift}}. Due to the {{w|Doppler effect}}, objects that are moving toward an observer appear bluer than they actually are (known as blueshift). Objects moving away from the observer (e.g. objects viewed in the rear-view mirror of a moving vehicle) appear redder than they actually are (known as redshift), and thus the objects are in reality bluer than they appear. This is generally relevant only in terms of high speed motion such as observation of the expansion of the universe in astrophysics. The joke is that the relative speed of any object visible in a side-view mirror would create an insignificant and unobservable redshift.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>This comic is a reference to the <ins class="diffchange diffchange-inline">phenomenon </ins>known as {{w|redshift}}/{{w|blueshift}}. Due to the {{w|Doppler effect}}, objects that are moving toward an observer appear bluer than they actually are (known as blueshift). Objects moving away from the observer (e.g. objects viewed in the rear-view mirror of a moving vehicle) appear redder than they actually are (known as redshift), and thus the objects are in reality bluer than they appear. This is generally relevant only in terms of high speed motion such as observation of the expansion of the universe in astrophysics. The joke is that the relative speed of any object visible in a side-view mirror would create an insignificant and unobservable redshift.</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Another possible explanation is that the redshift refers to the actual reflection itself.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Another possible explanation is that the redshift refers to the actual reflection itself. As photons are reflected in a mirror, momentum is transferred and thereby they lose a very small amount of energy. This loss of energy results in a slight redshift of the light. (This effect is similar to {{w|compton scattering}}.)</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>As photons are reflected in a mirror, momentum is transferred and thereby they lose a very small amount of energy. This loss of energy results in a slight redshift of the light. (This effect is similar to {{w|compton scattering}}.)</div></td><td colspan="2">&#160;</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Edwin Hubble was an astronomer credited ({{w|Stigler's law of eponymy|amid some controversy}}) with &quot;{{w|Hubble's Law}},&quot; which states that a Doppler shift can be observed for objects in deep space moving with relative velocity to Earth and that their velocity is proportional to their distance from Earth. Probably the most famous application of the law was measurement of relative velocities of galaxies, such as those seen in the picture known as {{w|Hubble Deep Field}}, taken by the {{w|Hubble Space Telescope}}. The results proved that most galaxies keep getting farther apart as a result of expansion of the universe. This is one of many pieces of evidence supporting the {{w|Big Bang}} theory.</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Edwin Hubble was an astronomer credited ({{w|Stigler's law of eponymy|amid some controversy}}) with &quot;{{w|Hubble's Law}},&quot; which states that a Doppler shift can be observed for objects in deep space moving with relative velocity to Earth and that their velocity is proportional to their distance from Earth. Probably the most famous application of the law was measurement of relative velocities of galaxies, such as those seen in the picture known as {{w|Hubble Deep Field}}, taken by the {{w|Hubble Space Telescope}}. The results proved that most galaxies keep getting farther apart as a result of expansion of the universe. This is one of many pieces of evidence supporting the {{w|Big Bang}} theory.</div></td></tr> </table>

Pressforaction https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=304593&oldid=prev 2023-01-11T23:28:51Z

<p>‎<span dir="auto"><span class="autocomment">Transcript: </span> cat</span></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr style="vertical-align: top;" lang="en"> <td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 23:28, 11 January 2023</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l25" >Line 25:</td> <td colspan="2" class="diff-lineno">Line 25:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>{{comic discussion}}</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>{{comic discussion}}</div></td></tr> <tr><td colspan="2">&#160;</td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">[[Category:Cosmology]]</ins></div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Physics]]</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Physics]]</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Comics with color]]</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Comics with color]]</div></td></tr> </table>

Natg19 https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=283232&oldid=prev 2022-05-26T19:58:05Z

<p>Reverted edits by <a href="/wiki/index.php/Special:Contributions/Donald_Trump" title="Special:Contributions/Donald Trump">Donald Trump</a> (<a href="/wiki/index.php?title=User_talk:Donald_Trump&amp;action=edit&amp;redlink=1" class="new" title="User talk:Donald Trump (page does not exist)">talk</a>) to last revision by <a href="/wiki/index.php/User:CRLF" title="User:CRLF">CRLF</a></p> <a href="//www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&amp;diff=283232&amp;oldid=282134">Show changes</a>

Theusaf https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=282134&oldid=prev 2022-05-26T19:04:26Z

<p>Reverted edit by anti-crap user</p> <a href="//www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&amp;diff=282134&amp;oldid=279907">Show changes</a>

Donald Trump https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=279907&oldid=prev 2022-05-26T17:51:25Z

<p>Reverted vandalism with <a href="/wiki/index.php/User:CRLF/OneClickUndo.js" title="User:CRLF/OneClickUndo.js">User:CRLF/OneClickUndo.js</a></p> <a href="//www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&amp;diff=279907&amp;oldid=278759">Show changes</a>

CRLF https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=278759&oldid=prev 2022-05-26T17:24:13Z

<p>Reverted edit by anti-crap user</p> <a href="//www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&amp;diff=278759&amp;oldid=276555">Show changes</a>

Donald Trump https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=276555&oldid=prev 2022-05-23T18:46:14Z

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CRLF https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=274532&oldid=prev 2022-05-23T18:16:32Z

<p>haha your js cant stop my js</p> <a href="//www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&amp;diff=274532&amp;oldid=273067">Show changes</a>

Xray Kilo Charlie Delta https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=273067&oldid=prev 2022-05-21T02:53:37Z

<p>Reverted edits by <a href="/wiki/index.php/Special:Contributions/Explain_xkcd_server_admin" title="Special:Contributions/Explain xkcd server admin">Explain xkcd server admin</a> (<a href="/wiki/index.php?title=User_talk:Explain_xkcd_server_admin&amp;action=edit&amp;redlink=1" class="new" title="User talk:Explain xkcd server admin (page does not exist)">talk</a>) to last revision by <a href="/wiki/index.php/User:Theusaf" title="User:Theusaf">Theusaf</a></p> <a href="//www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&amp;diff=273067&amp;oldid=271575">Show changes</a>

Davidy22 https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=271575&oldid=prev 2022-05-20T21:57:10Z

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