https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&feedformat=atom&user=Gruauder 2026-04-20T18:51:12Z User contributions MediaWiki 1.30.0 https://www.explainxkcd.com/wiki/index.php?title=1125:_Objects_In_Mirror&diff=15534 2012-10-26T00:24:15Z

<p>Gruauder: Add alternative explanation for the title text</p> <hr /> <div>{{comic<br /> | number = 1125<br /> | date = October 24, 2012<br /> | title = Objects In Mirror<br /> | image = objects in mirror.png<br /> | imagesize = <br /> | titletext = Universes in mirror, like those in windshield, are larger than they appear.<br /> }}<br /> <br /> ==Explanation==<br /> For all people who are not from USA, India, Canada, Korea, and Australia: &quot;Objects in mirror are closer than they appear&quot; is a required, although ridiculous &quot;safety warning&quot;, required to be engraved on passenger side mirrors of motor vehicles.<br /> <br /> This comic is a reference to the phenomena 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 rear-view mirror would create an insignificant and unobservable redshift.<br /> <br /> Edwin Hubble was an astronomer credited ({{w|Stigler's law of eponymy|amid some controversy}}) with &quot;Hubble's Law,&quot; which states that a Doppler shift can be observed for objects in space moving with relative velocity to 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 was one of many evidences towards the {{w|Big Bang}} theory.<br /> <br /> The title text may be a reference to comic [[1110: Click and Drag]]. Or maybe the title text references that we see the universe as it was in the past, when it was smaller than it is today.<br /> <br /> ==Transcript==<br /> :[View of a car mirror that reads &quot;Objects in mirror are bluer than they appear&quot;]<br /> :Caption: Edwin Hubble's car<br /> <br /> {{comic discussion}}</div>

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