Editing Moon (section)

===Illumination and phases===
{{See also|Lunar phase|Moonlight|Halo (optical phenomenon)}}
[[File:Moon phases en.jpg|center|thumb|550x550px|The monthly changes in the angle between the direction of sunlight and view from Earth, and the [[Lunar phase|phases of the Moon]] that result, as viewed from the [[Northern Hemisphere]]. The [[Earth–Moon distance]] is not to scale.]]

The Moon rotates, as it orbits Earth, changing orientation toward the Sun, experiencing a [[lunar day]]. A lunar day is equal to one [[lunar month]] (one synodic orbit around Earth) due to it being [[tidal locking|tidally locked]] to Earth. Since the Moon is not tidally locked to the Sun, lunar daylight and night times both occur around the Moon. The changing position of the illumination of the Moon by the Sun during a lunar day is observable from Earth as the changing [[lunar phase]]s, waxing crescent being the sunrise and the waning crescent the sunset phase of a day observed from afar.<ref name="r040">{{cite web | title=Phases of the Moon explained | website=BBC Sky at Night Magazine | date=January 21, 2025 | url=https://www.skyatnightmagazine.com/space-science/why-does-the-moons-appearance-change | access-date=April 29, 2025}}</ref>

Lunar night is the darkest on the far side and during lunar eclipses on the near side (and darker than a moonless night on Earth). The near side is during its night illuminated by [[Earthlight (astronomy)|Earthlight]], making the near side illuminated enough by the Earthlight to see lunar surface features from Earth where it is dark during its night phase due to Earthlight being reflected back to Earth. Earthshine makes the night on the near side about 43 times brighter, and sometimes even 55 times brighter than a night on Earth illuminated by the light of the full moon.<ref name="u988">{{cite web | last=Siegel | first=Ethan | title=Ask Ethan: How Bright Is The Earth As Seen From The Moon? | website=Forbes | date=March 18, 2017 | url=https://www.forbes.com/sites/startswithabang/2017/03/18/ask-ethan-how-bright-is-the-earth-as-seen-from-the-moon/ | access-date=April 29, 2025}}</ref>

In Earth's sky brightness and apparent size of the Moon changes also due to its elliptic [[Orbit of the Moon|orbit around Earth]]. At [[perigee]] (closest), since the Moon is up to 14% closer to Earth than at [[apogee]] (most distant), it subtends a [[solid angle]] which is up to 30% larger. Consequently, given the same phase, the Moon's brightness also varies by up to 30% between apogee and perigee.<ref>{{cite web |url=http://www.space.com/34515-supermoon-guide.html |title=Supermoon November 2016 |date=November 13, 2016 |access-date=November 14, 2016 |publisher=Space.com |url-status=live |archive-url=https://web.archive.org/web/20161114220725/http://www.space.com/34515-supermoon-guide.html |archive-date=November 14, 2016}}</ref> A full (or new) moon at such a position is called a [[supermoon]].<ref name="size1">{{cite web |title=Super Full Moon |date=March 16, 2011 |author=Tony Phillips |publisher=NASA |access-date=March 19, 2011 |url=https://science.nasa.gov/science-news/science-at-nasa/2011/16mar_supermoon/ |url-status=dead |archive-url=https://web.archive.org/web/20120507035348/https://science.nasa.gov/science-news/science-at-nasa/2011/16mar_supermoon/ |archive-date=May 7, 2012}}</ref><ref name="size2">{{cite news |title=Full moon tonight is as close as it gets |date=March 18, 2011 |author=Richard K. De Atley |newspaper=[[The Press-Enterprise]] |access-date=March 19, 2011 |url=http://www.pe.com/localnews/stories/PE_News_Local_D_moon19.23a6364.html |url-status=dead |archive-url=https://web.archive.org/web/20110322161600/http://www.pe.com/localnews/stories/PE_News_Local_D_moon19.23a6364.html |archive-date=March 22, 2011}}</ref><ref>{{cite news |url=https://www.theguardian.com/science/2011/mar/19/super-moon-closest-point-years |title='Super moon' to reach closest point for almost 20 years |newspaper=The Guardian |date=March 19, 2011 |access-date=March 19, 2011 |url-status=live |archive-url=https://web.archive.org/web/20131225175506/http://www.theguardian.com/science/2011/mar/19/super-moon-closest-point-years |archive-date=December 25, 2013}}</ref>

====Observational phenomena====
There has been historical controversy over whether observed features on the Moon's surface change over time. Today, many of these claims are thought to be illusory, resulting from observation under different lighting conditions, poor [[astronomical seeing]], or inadequate drawings. However, [[outgassing]] does occasionally occur and could be responsible for a minor percentage of the reported [[lunar transient phenomena]]. Recently, it has been suggested that a roughly {{convert|3|km|abbr=on}} diameter region of the lunar surface was modified by a gas release event about a million years ago.<ref>{{cite journal |last=Taylor |first=G. J. |date=November 8, 2006 |title=Recent Gas Escape from the Moon |url=http://www.psrd.hawaii.edu/Nov06/MoonGas.html |url-status=dead |journal=Planetary Science Research Discoveries |page=110 |bibcode=2006psrd.reptE.110T |archive-url=https://web.archive.org/web/20070304055515/http://www.psrd.hawaii.edu/Nov06/MoonGas.html |archive-date=March 4, 2007 |access-date=April 4, 2007}}</ref><ref>{{cite journal |last1=Schultz |first1=P. H. |last2=Staid |first2=M. I. |last3=Pieters |first3=C. M. |date=2006 |title=Lunar activity from recent gas release |journal=[[Nature (journal)|Nature]] |volume=444 |issue=7116 |pages=184–186 |bibcode=2006Natur.444..184S |doi=10.1038/nature05303 |pmid=17093445 |s2cid=7679109}}</ref>