Editing Red (section)

=== Astronomy ===
* [[Mars]] is called the Red Planet because of the reddish color imparted to its surface by the abundant [[iron oxide]] present there.<ref>{{cite web |url=http://www.cs.ucf.edu/~MidLink/Mars.html|title=Mars, The Red Planet|last1=Adams|first1=Melanie |last2=Raynor |first2=Natasha|date=Sep 19, 1994 – Mar 12, 2009 |website=MidLink Magazine|publisher=North Carolina State University |archive-url=https://web.archive.org/web/20070712223543/http://www.cs.ucf.edu/~MidLink/Mars.html|archive-date=July 12, 2007|url-status=dead|access-date=12 April 2010}}</ref>
* Astronomical objects that are moving away from the observer exhibit a Doppler [[redshift|red shift]].
* [[Jupiter]]'s surface displays a [[Great Red Spot]] caused by an oval-shaped mega storm south of the planet's [[equator]].<ref>{{cite web|title=The Great Red Spot |url=http://csep10.phys.utk.edu/astr161/lect/jupiter/redspot.html|last1=Cardall |first1=Christian|last2=Daunt |first2=Steven|year=2003|website=The Solar System |publisher=University of Tennessee|url-status=dead|archive-url=https://web.archive.org/web/20100331125637/http://csep10.phys.utk.edu/astr161/lect/jupiter/redspot.html |archive-date=March 31, 2010|access-date=Apr 12, 2010}}</ref>
* [[Red giant]]s are stars that have exhausted the supply of [[hydrogen]] in their cores and switched to [[thermonuclear fusion]] of hydrogen in a shell that surrounds its core. They have radii tens to hundreds of times larger than that of the [[Sun]]. However, their outer envelope is much lower in temperature, giving them an orange hue. Despite the lower energy density of their envelope, red giants are many times more luminous than the Sun due to their large size.
* [[Red supergiant]]s like [[Betelgeuse]], [[Antares]], [[Mu Cephei]], [[VV Cephei]], and [[VY Canis Majoris]] one of the [[List of largest known stars|biggest stars]] in the [[Universe]], are the biggest variety of red giants. They are huge in size, with radii 200 to 1700 times greater than the Sun, but relatively cool in temperature (3000–4500 K), causing their distinct red tint.
* A [[red dwarf]] is a small and relatively [[temperature|cool]] [[star]], which has a mass of less than half that of the [[Sun]] and a surface temperature of less than 4,000&nbsp;[[kelvin|K]]. Red dwarfs are by far the most common type of star in the Galaxy, but due to their low luminosity, from Earth, none are visible to the naked eye.<ref>{{Cite web|title=The Brightest Red Dwarf |last=Croswell|first=Ken|website=kencroswell.com |url=http://kencroswell.com/thebrightestreddwarf.html |access-date=Nov 23, 2018 |archive-url=https://web.archive.org/web/20181020223954/http://www.kencroswell.com/thebrightestreddwarf.html|archive-date=October 20, 2018|url-status=live}}</ref>
* [[Interstellar reddening]] is caused by the extinction of radiation by dust and gas

<gallery mode="packed" heights="150px">
Mars atmosphere 2.jpg|[[Mars]] appears to be red because of [[iron oxide]] on its surface.
Mira 1997.jpg|[[Mira]], a [[red giant]]
File:RedDwarfNASA.jpg|Artist's impression of a [[red dwarf]], a small, relatively cool star that appears red due to its temperature
</gallery>