|Location of Mare Imbrium|
|See also Gazetteer of Planetary Nomenclature|
The Mare Imbrium ( latin for sea of rain or rain sea , as was formerly held the dark plains for seas) is after the Oceanus Procellarum the second largest Mare of the Earth's moon . The roughly circular, basalt-filled basin of the rain sea was created by the penultimate of the really large, mare-forming impacts of asteroids during the so-called last big bombardment ; only the Mare Orientale is selenologically younger. With the Imbrian impact 3.8 to 3.9 billion years ago, the nectar age ended on the lunar timescale , and the Imbrian age began.
The Mare Imbrium dominates the northern center of the earth-facing side of the moon. The selenographic coordinates of the center of the rain sea are given by the International Astronomical Union (IAU) and the United States Geological Survey (USGS) as 34.72 ° North and 14.91 ° W, and the diameter is 1146 kilometers. Its area is about 830,000 km²; that is more than twice the area of Germany .
In the west, the basalt plain of the Mare Imbrium merges into the Oceanus Procellarum. In the north-west lies the rainbow bay ( Sinus Iridum ) as the “marginal sea” of the rain sea . In the north, the Montes Alpes ("Moon Alps ") separate the Sea of Rain from the Mare Frigoris . Within the Alps, on the edge of the rain sea of diameter 101 km wide, with basalt -filled crater Plato . In the east Mare Imbrium is in a relatively narrow region between the two ends of the chain Mountain Montes Apenninus and Montes Caucasus in the Mare Serenitatis over. To the southwest of it, on the southeastern edge of the rainy sea, lie the “Swamp of Putrefaction” ( Palus Putredinis ) and the 82 km wide Archimedes crater, also filled with basalt . In the southern vicinity of the rain sea are the "Bay of the Middle" ( Sinus Medii ), the Mare Insularum and the 93 kilometer wide Copernicus crater .
The Imbrium Basin is shaped by at least three circular, concentric mountain rings that were created by the impact of the asteroid. But they are not as well preserved as the almost complete multi-ring system around the Mare Orientale . The outer ring has a diameter of around 1,300 kilometers and is divided into different sections: the Carpathian Mountains in the south, the Apennines in the southeast and the Caucasus in the east. In addition to the outer ring, William Hartmann and Gerard Kuiper discovered remains of two inner rings in 1962 . The middle ring with a diameter of around 1000 kilometers is marked by the Alps and the mountain regions at the Archimedes and Plato craters and at the Montes Jura . The inner ring with a diameter of around 700 kilometers is mostly buried under marebasalt. Only a few Marerücken and the mountain peaks Mons La Hire , Montes Recti , Montes Teneriffe , Mons Pico and Montes Spitzbergen rise above the Mare plain and form a rough ring pattern together with Cape Laplace .
The Apennine Mountains form the largest mountain range on the moon and reach heights of 4 to 5 kilometers above the level of the rainy sea. Other lunar researchers have suggested alternative views of the concentric ring structures of the basin with up to six rings involved. It has not yet been found out why long stretches of the large Apennine ring - such as at the transition to the Oceanus Procellarum - are missing marking elevations.
The lava cover that forms the Mare Imbrium in the Imbrium Basin is up to five kilometers thick. In the center under the mare there is a lunar mass concentration - a gravity anomaly that corresponds to a mass excess of 0.015 to 0.045 percent of the lunar mass. It causes a change in the orbital level for overflying lunar satellites of about 60 to 100 meters.
Grove Karl Gilbert was the first to notice that many elongated and valley-like formations on the lunar surface are radially aligned with the Mare Imbrium. He concluded from this that the original surface was reshaped by a very large impact that created the Imbrium Basin and changed the environment accordingly through the ejection material. In a publication from 1893, he introduced the term "Imbrium Sculpture" for the entirety of the structures shaped by the Imbrium impact.
In 1962, William Hartmann and Gerard Kuiper described in the journal "Communications of the Lunar and Planetary Laboratory" how the Imbrium Basin was formed by an impact. The impact that produced the rain sea was the second largest in lunar history. Its kinetic energy of the order of magnitude of 10 27 joules was so great that a hundred times more energy would have been enough to completely smash the moon. The impact formed a comprehensive pattern of radial and concentric faults around the impact crater beyond the three mountain rings . This pattern also includes deep grooves that are believed to have been plowed into the lunar soil by material that was thrown out at a shallow angle when it was hit. At the opposite place on the back of the moon , in the focus of the seismic waves converging there, lies a chaotic terrain. The connection with the Imbrium impact is confirmed by computer simulations, according to which this area was torn up by 10 meters by the impact.
In a period of time from 3.7 to 3.2 billion years ago, the basin was filled with lava from the magma of the lunar interior via cracks in the ground , so that the basaltic Mare plain, visible today, with a maximum difference in altitude of 100 meters and the characteristic dark color, was created. Most of the existing basalt surface was formed around 3.3 billion years ago.
Between the Archimedes and Autolycus craters , a little closer to Autolycus, is the impact site of the Soviet Lunik 2 probe , which was the first man-made object to reach the moon on September 13, 1959.
On July 31, 1971, the American manned mission Apollo 15 landed for two days next to the Hadley Rille at the foot of the Hadley Apennines, where traces of the asteroid impact should also be found. The exact age of the Imbrium Basin could be determined on the basis of the found breccias and other impact rocks. As with the Apollo missions 12 , 14 and 16 , an autonomous base station with experiments ( ALSEP ) was installed on the lunar surface. Among other things, it was equipped with a seismometer that could provide valuable data, including on seismic activities at the edge of the rainy sea.
The Mare Imbrium was explored in its opposite, north-western edge region from November 17, 1970 to October 4, 1971 by the Soviet side by the unmanned moon rover Lunochod 1 , which was controlled from Earth . The "moon mobile" drove about 10.5 kilometers through the Mare Plain and, in addition to a large number of images, above all provided data on the physical properties of the local regolith .
On December 14, 2013, the Chinese Chang'e-3 space probe landed in the north of the Mares, east of the Sinus Iridum . She had dropped off the Rover Yutu , which could travel a total of 114 meters. The landing site was officially named Guang Han Gong on October 5, 2015, after the moon palace in Chinese mythology, in which the moon goddess Chang'e and her companion Yutu live.
The name Mare Imbrium was first used by Giovanni Riccioli in 1651. In the following centuries the names Mare Austriacum (after Michael Florent van Langren , called Langrenus, 1645) and Lacus Marinus (after Johannes Hevelius ) were also in use. It was not until the 19th century that the name Riccioli prevailed for the lunar structures, and the name Mare Imbrium was confirmed as the official name by the IAU in 1935. By naming the mare in detail, Riccioli recorded the popular belief of the time that the various dark spots during their lighting phases had a special influence on the weather.
- Charles A. Wood: Around the Mare Imbrium . In: Astronomy Today , June 2005 . Spectrum of Science Verlag, p. 48-49 ( online [accessed November 24, 2009]).
- Gerald North: Watching the moon . Spektrum Akademischer Verlag, Heidelberg · Berlin 2003, ISBN 3-8274-1328-1 (English: Observing the moon. The modern astronomer's guide . Translated by Rainer Riemann and Stephan Fichtner).
- IN Galkin, WW Schwarew: Journey to the center of the moon. (= Small Natural Science Library. Volume 46). MIR, Moscow 1980, 1983, BSB BG Teubner, Leipzig 1980, 1983. (data on impact and age)
- Mare Imbrium in the Gazetteer of Planetary Nomenclature of the IAU (WGPSN) / USGS
- Mare Imbrium on The-Moon Wiki
- Spektrum.de : Amateur recordings     
- USGS: Mare Imbrium. Retrieved April 4, 2015 .
- A. Rükl : Moon Atlas . Verlag Werner Dausien, Hanau 1990, ISBN 3-7684-2047-3 ( formally incorrect ) , p. 48 .
- C. A. Wood: Around the Mare Imbrium. Pp. 48-49.
- Galkin, Schwarew: Journey to the center of the moon. P. 67.
- Alan Chu, Wolfgang Paech, Mario Weigand: Photographic moon atlas . Oculum-Verlag, Erlangen 2010, ISBN 978-3-938469-41-5 , p. 14.
- 1893: Grove Karl Gilbert (1843–1918): "The Moon's face, a study of the origin of its features" Philosophical Society of Washington Bulletin 12
- G. North: Watching the Moon. P. 220 (see literature)
- Hans Ulrich Keller (ed.): Das Kosmos Himmelsjahr 1995 . Franckh Kosmos Verlag, Stuttgart 2004, , p. 183.
- Kelly Beatty: Lots of Lunar Layers Under Chang'e 3 on Skyandtelescope.com
- Guang Han Gong in the Gazetteer of Planetary Nomenclature of the IAU (WGPSN) / USGS
- Katharina Kramer: The moon is making waves. The names of the lunar seas reflect the history of science and popular belief . In: mare . No. 35 , December 2002, p. 58 ( excerpt [accessed on April 4, 2015]). Text excerpt ( memento of the original from April 9, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.