Mare Imbrium

The Mare Imbrium (Latin for Sea of ​​Rains rain or sea, since sooner the dark plains of seas kept ) is after the Oceanus Procellarum is the second largest of the Earth's moon Mare. The approximately circular, basalt -filled basins of the ocean rain is caused by the last but one of the truly great, Mare -forming impacts ( impact event ) of asteroids during the so-called last major bombing; only the Mare Orientale is selenologisch younger. With the Imbrium impact prior to 3.8 to 3.9 billion years ending on the lunar timescale nektarische the age, and the imbrische era begins.

The Mare Imbrium dominates the northern center of the moon erdzugewandten page. The selenographic coordinates of the center of the rain the sea are of the International Astronomical Union ( IAU ) and the United States Geological Survey (USGS ) at 32.8 N 15.6 W and specify the diameter of 1123 km. Its surface area is approximately 830,000 km ²; which is more than twice the area of Germany.

Environment

In the west the basalt of Mare Imbrium level goes into the Oceanus Procellarum. To the northwest lies as " marginal sea " of rain sea the Bay of Rainbows ( Sinus Iridium ). In the north the Montes Alpes ( " Alpine Moon " ) separate the sea from the rain Mare Frigoris. Within the Alps, on the edge of the sea of ​​rain in diameter 101 km wide, filled with basalt crater Plato. In the east the Mare Imbrium is in a relatively narrow area between the two ends of the cordillera and Montes Caucasus Montes Apenninus in the Mare Serenitatis on. Southwest of them are located on the southeastern edge of the rain sea the " morass of putrefaction " ( Palus Putredinis ) and 82 kilometers wide, also filled with basalt crater Archimedes. In the southern neighborhood of the rain the sea "Bay of the center" are (sine Medii ), the Mare Insularum and 93 km wide crater Copernicus.

Mountain ranges

The Imbrium basin is characterized by at least three circular concentric mountain rings caused by the impact of asteroids. But you are not as well preserved as the almost complete multi-ring system around the Mare Orientale. The outer ring has a diameter of about 1,300 kilometers and is divided into different sections: in the Carpathian Mountains in the south, the Apennine Mountains to the southeast and the Caucasus in the east. In addition to the outer ring discovered in 1962 William Hartmann and Gerard Kuiper remains of two inner rings. The middle ring with a diameter of about 1000 km mark the Alps and the mountain regions of the craters Archimedes and Plato, as well as the Montes Jura. The inner ring with a diameter of about 700 kilometers is buried for the most part under Mare basalt. Only isolated Mare back and the mountain peaks Mons La Hire, Montes Recti, Montes Teneriffe, Mons Pico and Montes Spitzbergen rise above the Mare - level and forms together with the Cape Laplace a rough ring pattern.

The Apennine Mountains form the largest mountain chain of the moon and reach heights 4-5 km above the level of the sea rain. The Course of the concentric ring structures of the pelvis other lunar researchers have also proposed alternative views with up to six rings involved. Why the great Apennine ring over long distances - such as the transition to the Oceanus Procellarum - marked relief elevations missing, has not yet been found.

Underground

The lava bed that forms the Mare Imbrium in the Imbrium basin is thick up to five kilometers. In the center under the Mare is a lunar mass concentration - a gravity anomaly, which corresponds to a mass excess from 0.015 to 0.045 percent of the lunar mass. It causes a change in orbital altitude for overflying lunar satellite from about 60 to 100 meters.

Formation

As first described William Hartmann and Gerard Kuiper in 1962 in the journal " Communications of the Lunar and Planetary Laboratory ," the origin of the Imbrium basin by a strike. The impact that produced the Sea of ​​Rains, was the second largest in the Moon 's history. Its kinetic energy of the order of 1027 joules was so great that even a hundred times more energy would have been enough to completely destroy the moon. The impact formed on the three mountain rings, a comprehensive pattern of radial and concentric faults of the impact crater. For this pattern include deep grooves, which are believed to have been plowed through material in the lunar soil, which was flung out when at a shallow angle. At the opposite place on the moon back, the focus of there converging seismic waves is a chaotic terrain. The link with the Imbrium impact is confirmed by computer simulations, after which the area was torn up by the impact effect by 10 yards.

In a period from before 3.7 until 3.2 billion years, the basin above the ground columns filled with lava from the magma of the lunar interior, so that the visible today basaltic Mare plane originated with 100 meters height difference and the characteristic dark color. The largest part of the present basalt surface is formed about 3.3 billion years.

Space missions

Between the craters Archimedes, and Autolycus, a little closer to Autolycus, is the impact site of the Soviet probe Lunik 2, which was the first man-made object reached the moon on September 13, 1959.

On 31 July 1971, the manned American Apollo 15 mission landed for two days next to the Hadley Rille at the foot of the Hadley - Apennine, where traces of the asteroid should be find. On the basis of the found breccias and further impact rocks the exact age of the Imbrium basin could be determined. As with the Apollo missions 12, 14 and 16 an autonomous base station with experiments ( ALSEP ) was installed on the lunar surface. She was equipped among other things with a seismometer, which could provide valuable data, even on seismic activity on the edge of the rain sea.

The Mare Imbrium was explored in its opposite, northwestern edge region of 17 November 1970 to October 4, 1971 by the Soviet side by the unmanned, controlled from Earth Moon Rover Lunokhod 1. The "moon - mobile " drove about 10.5 kilometers through the Mare - level and provided in addition to a large number of images, especially data on the physical properties of the local regolith.

The Chinese space probe Chang'e -3 is in the sinus iridium (rain Bay ) on 14 December 2013 at 21.11 clock (UTC 8) successfully landed. A lunar rover named Yutu should then be on the lunar surface in operation for three months.

Name

The name Mare Imbrium was first used by Giovanni Riccioli in 1651. In the following centuries, the names were austriacum Mare ( by Michael Florent van Langren called Langrenus, 1645 ) and Lacus Marinus (after Johannes Hevelius ) in use. Only in the 19th century advocated the moon structures, the designation referred to by Riccioli, and the name of Mare Imbrium was confirmed by the IAU in 1935 officially. With the naming of Mary in detail Riccioli held the then popular belief, the lighting during their phases attributed to the different dark spots a special influence on the weather.