Messier is a relatively young

lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

located on the

Mare Fecunditatis Mare Fecunditatis (Latin ''fēcunditātis'', the "Sea of Fecundity" or "Sea of Fertility") is a lunar mare in the eastern half of the visible Moon. The mare has a maximum diameter of 840 km. __NOTOC__ Description The Fecunditatis basin forme ...

. The crater has a discernible

oblong An oblong is a non-square rectangle. Oblong may also refer to: Places * Oblong, Illinois, a village in the United States * Oblong Township, Crawford County, Illinois, United States * A strip of land on the New York-Connecticut border in the Unit ...

shape that is not caused by foreshortening. The longer dimension is oriented in an east–west direction. Just to the west lies Messier A, a similar-sized crater with an oblong, doublet form. The longer dimension of this crater is oriented north–south, at

right angle In geometry and trigonometry, a right angle is an angle of exactly 90 Degree (angle), degrees or radians corresponding to a quarter turn (geometry), turn. If a Line (mathematics)#Ray, ray is placed so that its endpoint is on a line and the ad ...

s to Messier. This crater also has a curved bulge extending to the west. Messier and Messier A were photographed at high resolution by NASA's

Lunar Orbiter 5 Lunar Orbiter 5, the last of the "Lunar Orbiter series", was designed to take additional Apollo and Surveyor landing site photography and to take broad survey images of unphotographed parts of the Moon's far side. It was also equipped to collec ...

spacecraft In August 1967. The Lunar Orbiter V_041 image is archived at the

Lunar and Planetary Institute The Lunar and Planetary Institute (LPI) is a scientific research institute dedicated to study of the Solar System, its formation, evolution, and current state. The Institute is part of the Universities Space Research Association (USRA) and is supp ...

br>website
The Lunar Orbiter V partial image shown here is derived from the

Lunar Orbiter Image Recovery Project The Lunar Orbiter Image Recovery Project (LOIRP) is a project to digitize the original analog data tapes from the five Lunar Orbiter spacecraft that were sent to the Moon in 1966 and 1967; it is funded by NASA, SkyCorp, SpaceRef Interactive, an ...

effort to reprocess these images from the original tapes. The interiors of Messier and Messier A have a higher

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

than the surrounding

mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than four ...

. There is also a dark streak in the center of each crater. Two prominent, nearly linear

rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...

extend westwards from the rim of Messier A, continuing over 100

kilometer The kilometre ( SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for ). It is now the measurement unit used for ex ...

s towards the west edge of

. The mare surface around the craters is also lightly marked by rays from other craters. It is theorized that Messier crater was formed by an impact at a very low angle, and that Messier A could have formed following a rebound by the impacting body. The low angle of impact may also explain the asymmetrical ray system. To the northwest of Messier A is a long, narrow

rille Rille (German for 'groove') is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is ''rima'', plural ''rimae''. Typically, a rille can be several kilometers wid ...

, called ''Rima Messier''. This crater is named in honor of the French

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

Charles Messier Charles Messier (; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the ''Messier objects''. Messier's purpose f ...

(1730–1817).

Satellite craters

By convention these features are identified on lunar

map A map is a symbolic depiction emphasizing relationships between elements of some space, such as objects, regions, or themes. Many maps are static, fixed to paper or some other durable medium, while others are dynamic or interactive. Although ...

s by placing the letter on the side of the crater midpoint that is closest to Messier. The following crater has been renamed by the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

. * Messier G - ''See''

Lindbergh (crater) Lindbergh is a small lunar impact crater that is located in the western part of the Mare Fecunditatis. It lies to the west of the flooded crater Bilharz, and northeast of Ibn Battuta. Lindbergh was previously designated Messier G before being g ...

. Messier A has been called

W. H. Pickering William Henry Pickering (February 15, 1858 – January 16, 1938) was an American astronomer. Pickering constructed and established several observatories or astronomical observation stations, notably including Percival Lowell's Flagstaff Obser ...

, but this was never officially sanctioned by the IAU. A different crater has since been named for Pickering.

Gallery

AS11-42-6233.jpg, Near vertical view from

Apollo 11 Apollo 11 (July 16–24, 1969) was the American spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin landed the Apollo Lunar Module ''Eagle'' on July 20, 1969, at 20:17 UTC, an ...

AS14-73-10169.jpg, Oblique view from

Apollo 14 Apollo 14 (January 31, 1971February 9, 1971) was the eighth crewed mission in the United States Apollo program, the third to land on the Moon, and the first to land in the lunar highlands. It was the last of the " H missions", landings at s ...

AS15-90-12319 Messier crater.jpg, Photo taken by

Apollo 15 Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the United States' Apollo program and the fourth to Moon landing, land on the Moon. It was the first List of Apollo missions#Alphabetical mission types, J mission, with a ...

with high Sun, showing the prominent rays. AS15-M-2674.png, Apollo 15 Mapping Camera image Messier (LRO) 1.png, Photo taken by

Lunar Reconnaissance Orbiter The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions t ...

with low Sun, showing relief of ejecta. Messier Craters in Stereo.jpg, A stereo view of the craters (Apollo 11) Rima Messier 5042 med.jpg, Oblique view of Rima Messier from

References

Lunar crater references

* * * * * * * * * * * * {{refend

External links

*http://messier.seds.org/xtra/m-crater.html * Charles A. Wood
Messier on the Moon
Sky & Telescope, August 1, 2006 Impact craters on the Moon