View source for Mare Imbrium

{{short description|Vast lunar mare filling a basin on Earth's Moon}}
{{Use dmy dates|date=March 2019}}
{{Infobox Lunar mare
|name        = Mare Imbrium
|image       = Imbrium location.jpg
|caption     = A map showing the location of Mare Imbrium
|eponym      = Sea of Showers or Sea of Rains
|coordinates = {{coord|32.8|N|15.6|W|globe:moon_type:landmark|display=inline,title}}
|diameter    = {{convert|1146|km|mi|abbr=on}}<ref name=USGS>{{gpn|3678}}</ref>
}}

[[File:Mare Imbrium (LRO).png|thumb|right|[[Lunar Reconnaissance Orbiter|LRO]] mosaic of Mare Imbrium]]
[[File:Imbrium map.png|thumb|right|Detail map of Imbrium's features]]
[[File:Sunrise over Mare Imbrium.png|thumb|Mare Imbrium from Earth, imaged with an 8" untracked Dobsonian. The left panel emphasizes wrinkle ridges, craters, and mountain rings with the terminator closer. The right panel highlights albedo patterns and ray markings under a higher sun.]]
[[File:A17PSR-Fig4-63 AS17-155-23714-16.jpg|thumb|right|Detail of basaltic lava flow fronts within Mare Imbrium, located north of [[Euler (crater)|Euler]] crater. (Mosaic of [[Apollo 17]] images.)]]
'''Mare Imbrium''' {{IPAc-en|'|ɪ|m|b|r|i|ə|m}} ([[Latin]] ''imbrium'', the "'''Sea of Showers'''" or "'''Sea of Rains'''") is a vast [[lunar mare|lava plain]] within the Imbrium Basin on the [[Moon]] and is one of the [[larger craters in the Solar System]]. The Imbrium Basin formed from the collision of a [[Protoplanet|proto-planet]] during the [[Late Heavy Bombardment]]. Basaltic [[lava]] later flooded the giant [[Impact crater|crater]] to form the flat volcanic plain seen today. The basin's age has been estimated using [[Uranium–lead dating|uranium–lead dating methods]] to approximately 3.9 billion years ago, and the diameter of the impactor has been estimated to be 250 ± 25&nbsp;km.<ref>P. H. Schultz & D.A. Crawford, ''Origin and implications of non-radial Imbrium Sculpture on the Moon'', Nature '''535''', 391–394 (2016)</ref> The Moon's maria (plural of [[Lunar mare|mare]]) have fewer features than other areas of the Moon because molten lava pooled in the craters and formed a relatively smooth surface. Mare Imbrium is not as flat as it would have originally been when it first formed as a result of later events that have altered its surface. Mare Imbrium was the location of the first robotic [[Lunar rover |rover]] deployed on an extraterrestrial body.

== Origin ==
Mare Imbrium formed when a proto-planet from the asteroid belt collided with the Moon during the [[Late Heavy Bombardment]].<ref>{{Cite journal |last1=Merle |first1=R. E. |last2=Nemchin |first2=A. A. |last3=Grange |first3=M. L. |last4=Whitehouse |first4=M. J. |last5=Pidgeon |first5=R. T. |year=2014 |title=High resolution U-Pb ages of Ca-phosphates in Apollo 14 breccias: Implications for the age of the Imbrium impact |journal=Meteoritics & Planetary Science |volume=49 |issue=12 |pages=2241–2251 |bibcode=2014M&PS...49.2241M |doi=10.1111/maps.12395 |doi-access=free}}</ref> The impact is dated to approximately 3922 ± 12 million years ago, based on [[radiometric dating]] techniques. [[Ejecta]] from the impact covers large areas of the near side of the Moon.<ref>{{Cite journal |last1=Nemchin |first1=Alexander A. |last2=Long |first2=Tao |last3=Jolliff |first3=Bradley L. |last4=Wan |first4=Yusheng |last5=Snape |first5=Joshua F. |last6=Zeigler |first6=Ryan |last7=Grange |first7=Marion L. |last8=Liu |first8=Dunyi |last9=Whitehouse |first9=Martin J. |last10=Timms |first10=Nicholas E. |last11=Jourdan |first11=Fred |date=2021-04-01 |title=Ages of lunar impact breccias: Limits for timing of the Imbrium impact |journal=Geochemistry |language=en |volume=81 |issue=1 |article-number=125683 |doi=10.1016/j.chemer.2020.125683 |bibcode=2021ChEG...81l5683N |s2cid=224884243 |issn=0009-2819|doi-access=free |hdl=20.500.11937/90165 |hdl-access=free }}</ref><ref>{{Cite journal |last1=Zhang |first1=Bidong |last2=Lin |first2=Yangting |last3=Moser |first3=Desmond E. |last4=Hao |first4=Jialong |last5=Shieh |first5=Sean R. |last6=Bouvier |first6=Audrey |date=December 2019 |title=Imbrium Age for Zircons in Apollo 17 South Massif Impact Melt Breccia 73155 |url=https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JE005992 |journal=Journal of Geophysical Research: Planets |language=en |volume=124 |issue=12 |pages=3205–3218 |doi=10.1029/2019JE005992 |bibcode=2019JGRE..124.3205Z |s2cid=210277861 |issn=2169-9097|url-access=subscription }}</ref>

== Characteristics ==
With a diameter of 1145&nbsp;km, Mare Imbrium is second only to [[Oceanus Procellarum]] in size among the maria, and it is the largest mare associated with an impact basin.

The Imbrium Basin is surrounded by three concentric rings of mountains, uplifted by the colossal impact event that excavated it. The outermost ring of mountains has a diameter of 1300&nbsp;km and is divided into several different ranges; the [[Montes Carpatus]] to the south, the [[Montes Apenninus]] to the southeast, and the [[Montes Caucasus]] to the east. At their highest, the outer ring of mountains rise more than 5&nbsp;km above the surface of Mare Imbrium.<ref>[https://moonsummits.carrd.co The Moon's Highs and Lows]</ref> The ring mountains are not as well developed to the north and west, and it appears they were simply not raised as high in these regions by the Imbrium impact. The middle ring of mountains forms the [[Montes Alpes]] and [[Montes Archimedes]].
The innermost ring, with a diameter of 650&nbsp;km, is defined by [[Montes Recti]], [[Montes Teneriffe]], and possibly [[Montes Spitzbergen]]. Much of this ring is submerged under the mare's basalt, resulting in only isolated peaks remaining in some areas, such as [[Mons Pico]] and [[Mons La Hire]].
[[File:Mare Imbrium Si map.jpg|left|thumb|Selenochromatic Image (Si) of Mare Imbrium]]

Numerous estimates of the depth of the mare material have been made using various methods. These include analyses of gravity, seismic, and radar data; studies of craters partially filled with basalt and those that have completely penetrated the mare; and comparisons of lunar basins filled with mare deposits to unfilled basins. These studies have yielded depth estimates ranging from 2&nbsp;km<ref>{{cite journal
 | last1 = Thomson | first1 = B.J.
 | year = 2009
 | title = A new technique for estimating the thickness of mare basalts in Imbrium Basin
 | journal =  Geophysical Research Letters
 | volume = 36
| issue = 12
 | doi = 10.1029/2009GL037600
 | bibcode = 2009GeoRL..3612201T
 }}</ref>
to 5&nbsp;km<ref> {{cite journal
 | last1 = Dibb | first1 = S.D.
 | last2 = Kiefer  | first2 = W.S
 | year = 2015
 | title =  The Depth-Diameter relationship for large lunar impact basins and the implications for mare basalt thickness
 | journal = 46th LPSC 
 | volume = 1677
 | url = https://www.hou.usra.edu/meetings/lpsc2015/pdf/1677.pdf
}}</ref> in the central part of the mare. It is thought that the original crater left by the Imbrium impact was as much as 100 km deep, but that the floor of the basin bounced back upwards immediately afterwards.

[[File:Imbrium sculpture Ukert crater 3085 med.jpg|thumb|left|200px|Oblique view of Imbrium Sculpture, with the crater [[Ukert (crater)|Ukert]] right of center]]
Surrounding the Imbrium Basin is a region blanketed by [[ejecta]] from the impact, extending roughly 800&nbsp;km outward. Also encircling the basin is a pattern of radial grooves called the "Imbrium Sculpture", which have been interpreted as furrows cut in the Moon's surface by large projectiles blasted out of the basin at low angles, causing them to skim across the lunar surface ploughing out these features. The sculpture pattern was first identified by [[Grove Karl Gilbert]] in 1893.<ref>Gilbert, Grove Karl. [https://catalog.hathitrust.org/Record/100359666 The Moon's face, a study of the origin of its features.] Washington, Philosophical Society of Washington, 1893.</ref> Furthermore, a Moon-wide pattern of faults which run both radial to and concentric to the Imbrium basin were thought to have been formed by the Imbrium impact; the event literally shattered the Moon's entire [[lithosphere]]. At the region of the Moon's surface exactly opposite Imbrium Basin, there is a region of chaotic terrain (the crater [[Van de Graaff (crater)|Van de Graaff]]) which is thought to have been formed when the seismic waves of the impact were focused there after travelling through the Moon's interior. Mare Imbrium is about {{convert|750|mi|km}} wide.

A [[mass concentration (astronomy)|mass concentration]] (mascon), or gravitational high, was identified in the center of Mare Imbrium from Doppler tracking of the five [[Lunar Orbiter program|Lunar Orbiter]] spacecraft in 1968.<ref>{{cite journal | doi = 10.1126/science.161.3842.680 | title = Mascons: Lunar Mass Concentrations | year = 1968 | author = P. M. Muller, W. L. Sjogren | journal = Science | volume =  161 | issue = 3842  | pages = 680–684 | pmid=17801458|bibcode = 1968Sci...161..680M | s2cid = 40110502 }}</ref>  The Imbrium mascon is the largest on the Moon.  It was confirmed and mapped at higher resolution with later orbiters such as [[Lunar Prospector]] and [[Gravity Recovery and Interior Laboratory|GRAIL]].

<gallery heights="200px" mode="packed">
File:Imbrium basin topo.jpg|Shaded Relief map
File:Imbrium basin GRAIL gravity.jpg|Gravity map based on [[Gravity Recovery and Interior Laboratory|GRAIL]]
</gallery>

==Names==
Like most of the other maria on the Moon, Mare Imbrium was named by [[Giovanni Battista Riccioli|Giovanni Riccioli]], whose 1651 nomenclature system has become standardized.<ref>Ewen A. Whitaker, ''Mapping and Naming the Moon'' (Cambridge University Press, 1999), p. 61.</ref>

The earliest known name for the mare may be "The Shrine of [[Hecate]]"; [[Plutarch]] records that the [[Ancient Greeks]] gave this name to the largest of the "hollows and deeps" on the Moon, believing it to be the place where the souls of the deceased were tormented. Ewen A. Whitaker argues that this likely refers to Mare Imbrium, "the largest regular-shaped dark area unbroken by bright patches" that can be seen with the naked eye.<ref>Ewen A. Whitaker, ''Mapping and Naming the Moon'' (Cambridge University Press, 1999), p. 7</ref>

Around 1600, [[William Gilbert (astronomer)|William Gilbert]] made a map of the Moon that names Mare Imbrium "Regio Magna Orientalis" (the Large Eastern Region). [[Michael van Langren]]'s 1645 map named it "Mare Austriacum" (the Austrian Sea).<ref>Ewen A. Whitaker, ''Mapping and Naming the Moon'' (Cambridge University Press, 1999), pp. 15, 41.</ref>

==Observation and exploration==
Mare Imbrium is visible to the [[naked eye]] from Earth. In the traditional '[[Man in the Moon]]' image seen on the Moon in Western folklore, Mare Imbrium forms the man's right eye.<ref>Ewen A. Whitaker, ''Mapping and Naming the Moon'' (Cambridge University Press, 1999), p. 3. {{ISBN?}}</ref>

=== Luna 17 ===
On 17 November 1970 at 03:47 Universal Time, the Soviet spacecraft [[Luna 17]] made a soft landing in the mare, at latitude 38.28 N, and longitude 35.00 W. Luna 17 carried [[Lunokhod 1]], the first robotic [[Rover (space exploration)|rover]] to be deployed on the Moon or any extraterrestrial body. Lunokhod 1, a remote-controlled rover, was successfully deployed and undertook a mission lasting several months.

=== Apollo 15 ===
In 1971, the crewed [[Apollo 15]] mission landed in the southeastern region of Mare Imbrium, between [[Hadley–Apennine|Hadley Rille]] and the [[Montes Apenninus|Apennine Mountains]]. Commander [[David Scott]] and Lunar Module Pilot [[James Irwin]] spent three days on the surface of the Moon, including 18½ hours outside the spacecraft on lunar [[extra-vehicular activity]]. Command Module Pilot [[Alfred Worden]] remained in orbit and acquired hundreds of high-resolution photographs of Mare Imbrium (and other regions of the Moon) as well as other types of scientific data.  The crew on the surface explored the area using the first [[Lunar Roving Vehicle|lunar rover]] and [[Sample return mission|returned to Earth]] with {{convert|77|kg}} of lunar surface material.  Samples were collected from [[Mons Hadley Delta]], believed to be a fault block of pre-Imbrian ([[Nectarian]] or [[Pre-Nectarian]]) lunar crust, including the "[[Genesis Rock]]."  This was also the only Apollo mission to visit a lunar rille, and to observe outcrops of lunar bedrock visible in the rille wall.<ref>[https://www.hq.nasa.gov/alsj/a15/as15psr.pdf Apollo 15 Preliminary Science Report] (NASA SP-289), Scientific and Technical Information Office, National Aeronautics and Space Administration, Washington, D.C., 1972.</ref>

=== 2013 Impact ===
On 17 March 2013, an object hit the lunar surface in Mare Imbrium and exploded in a flash of [[apparent magnitude]] 4.<ref name="impact2013">{{cite web
  |date=17 May 2013
  |title=Bright Explosion on the Moon
  |publisher=Science@NASA
  |author=Dr. Tony Phillips
  |url=https://science.nasa.gov/science-news/science-at-nasa/2013/16may_lunarimpact/
  |access-date=2013-05-19}}</ref> The resulting crater was 18 meters wide.<ref name="newcratersonmoon">{{cite web
  |date=17 March 2015
  |title = New Craters on the Moon
  |publisher=Goddard Media Studios
  |author=NASA's Goddard Space Flight Center
  |url=https://svs.gsfc.nasa.gov/11806
  |access-date=2022-05-13}}</ref> This was the brightest impact recorded since NASA's lunar impact team began monitoring in 2005.

===Chinese landing===
{{Main|Chang'e 3|Yutu (rover)}}
[[File:Chang'e-3 lunar landing site.jpg|thumb|The planned landing site for [[Chang'e 3]] was [[Sinus Iridum]]. The actual landing took place on Mare Imbrium]]
Chang'e 3 landed on 14 December 2013 on Mare Imbrium, about 40&nbsp;km south of the 6&nbsp;km diameter ''Laplace F'' crater,<ref>{{cite web | url = http://planetary.s3.amazonaws.com/assets/images/3-moon/20131214_change_landing_location.jpg | title = Chang'e 3 landing coordinates | access-date = 2013-12-15 | date = 14 December 2013 | work = China News (CN)}}</ref><ref name='Landing in Mare Imbrium'>{{cite news | author1 = Emily Lakdawalla |author2=Phil Stooke | title = Chang'e 3 has successfully landed on the Moon! | date = December 2013 | url = http://www.planetary.org/blogs/emily-lakdawalla/2013/12140619-change-3-has-successfully-landed.html | work = The Planetary Society | access-date = 2013-12-15}}</ref>  at 44.1260°N 19.5014°W.<ref name='Landing in Mare Imbrium'/><ref>{{cite web | url = http://www.spaceflightnow.com/china/change3/131214landing/#.Uqzk7EAwCZA | title=China successfully lands robotic rover on the moon>}}</ref><ref>{{cite web | url= http://ww2.sinaimg.cn/mw1024/5f50f3afgw1ebjm28fzibj20v31rjgvr.jpg | title = Landing map of Chang'e 3 }}</ref>
The lander deployed the ''Yutu'' rover 7 hours and 24 minutes later.<ref>{{cite news | first = Ian | last = O'Neil | title = China's Rover Rolls! Yutu Begins Moon Mission | date = 14 December 2013 | publisher = CCTV | url = http://news.discovery.com/space/chinas-rover-rolls-yutu-begins-moon-mission-131214.htm | work = Discovery News | access-date = 2013-12-15 | archive-date = 3 March 2016 | archive-url = https://web.archive.org/web/20160303185633/http://news.discovery.com/space/chinas-rover-rolls-yutu-begins-moon-mission-131214.htm }}</ref> The Chang'e 3 mission attempted to perform the first direct measurement of the structure and depth of the [[lunar soil]] down to a depth of {{convert|30|m|ft|abbr=on}}, and investigate the [[Internal structure of the Moon|lunar crust structure]] down to several hundred meters deep.<ref name="xinhuanet.com/politics/2012-06/">{{Cite news |url=http://news.xinhuanet.com/politics/2012-06/14/c_112217044.htm |archive-url=https://web.archive.org/web/20120617020908/http://news.xinhuanet.com/politics/2012-06/14/c_112217044.htm |archive-date=17 June 2012 |title=欧阳自远：嫦娥三号明年发射将实现着陆器与月球车联合探测 |publisher=Xinhua|date=14 June 2012|access-date=23 July 2013}}</ref> The rover's ground penetrating radar found evidence of at least nine distinct [[rock layers]], indicating that the area had surprisingly complex geological processes and is compositionally distinct from the Apollo and Luna landing sites.<ref name="layered">{{cite news |last=Wall |first=Mike |url=http://www.space.com/28810-moon-history-chinese-lunar-rover.html?adbid=10152690360766466&adbpl=fb&adbpr=17610706465 |title=The Moon's History Is Surprisingly Complex, Chinese Rover Finds |work=Space.com |date=12 March 2015 |access-date=13 March 2015}}</ref><ref>{{cite journal |title=A young multilayered terrane of the northern Mare Imbrium revealed by Chang'E-3 mission |journal=Science |date=13 March 2015 |last=Xiao |first=Long |volume=347 |issue=6227 |pages=1226–1229 |doi=10.1126/science.1259866 |bibcode = 2015Sci...347.1226X |pmid=25766228|s2cid=206561783 }}</ref>

==See also==
* [[Sinus Iridum]]
* [[Sinus Lunicus]]
* [[Palus Putredinis]]
* [[Volcanism on the Moon]]

==References==
{{Reflist}}

==External links==
{{Commons category}}
* {{cite web
| last = Phillips
| first = Tony
| date = 2006-06-13
| url = https://science.nasa.gov/headlines/y2006/13jun_lunarsporadic.htm
| title = A Meteoroid Hits the Moon
| publisher = Science@NASA
| access-date = 2006-06-16
| archive-url = https://web.archive.org/web/20060616011442/http://science.nasa.gov/headlines/y2006/13jun_lunarsporadic.htm
| archive-date = 16 June 2006
}}
*[https://the-moon.us/wiki/Mare_Imbrium Mare Imbrium at The Moon Wiki]
*{{Cite APOD |date=28 December 2000|title=Moon Mare and Montes}} – one of the prominent features of the photo includes Mare Imbrium

{{Lunar maria}}

[[Category:Mare Imbrium| ]]
[[Category:Maria on the Moon|Imbrium, Mare]]