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Updated June 01, 2013
Called moon, all natural satellite of a planet, but the Moon, with a capital M, means the only natural satellite of Earth. The mean distance between Earth and the Moon is 384,403 km. The diameter of the Moon is 3474 km. The Hidden Side of the Moon is perpetually invisible from the Earth, it is impossible to take photographs of the face without the use of space probes. Intriguingly, the dark side is different from the face, both in terms of its average altitude and its rate of cratering.
Regularly, images and videos of the spectacular lunar surface and especially its dark side, we are sent by U.S. and Japanese probes.
U.S. Clementine mission had not seen the full moon but the probe Selene-Kaguya, the largest lunar mission since the Apollo program, launched in 2007, sent us photographs of a high accuracy of the order of 10 meters per pixel. This enabled the detection of new craters and thus to refine the measure of the rate of lunar cratering land. The dark side of the moon, we reached the large crater images Leibnitz (245 km diameter) crater Finsen (72 km diameter) crater Davisson (87 km diameter),... Credit: JAXA, NHK
Image: Retail seas and craters on the Moon.
Origin of the Moon
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The origin of the Moon is the subject of scientific debate. The analysis of lunar rocks highlights an interesting theory about the origin of the Moon.
These materials come from the mantle of two large planetary objects.
Shock of a huge shake the very young Earth in formation.
The companion of our nights might be a result of accretion of material ejected during the great crash. At the beginning of the creation of the Earth, a very large planetesimal the size of Mars, also a differential (metallic core, mantle,...) that a particular angle of impact and a relatively high speed, collided the Earth.
This collision caused the merger of the two metal cores, while the mantle materials of the two objects were thrown, but related to the Earth by gravity.
Most of its materials will slowly coalesce around what will become our Moon. All this happens very early in the history of the Earth, who does not keep track. Nevertheless, numerical simulations are able to represent fairly well in stages (see drawing opposite).
On the other hand, this assumption is not contradictory with what is currently known about the Moon and supports this idea.
Image: merger of the two metal cores, while the mantle materials are ejected but bound by gravity.
Image: accretion of matter ejected followed by formation of the satellite of the Earth, the Moon.
Craters of the Moon
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Image: The circular crater Plato
Diameter: 101 km Average Depth: 2300 meters
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Image: The crater Arzachel
Diameter: 96 km Average Depth: 3610 meters
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Image: The crater Copernicus
Diameter: 93 km Average Depth: 3760 meters
Image: The lunar terminator is the dividing line between day and night, it reveals the shadows of crater walls Hesiodus. The zoom on the left side of the image increases with the radius of the Sun which illuminates the crater 45 km in diameter, even in darkness.
image taken at 00:45 Friday, February 22, 2010 from Stuttgart, Germany. The large crater Pitatus 106 km in diameter in the center of the zoom, is beside Hesodius.
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Image: The crater Archimedes
Diameter: 83 km Average Depth: 2150 meters
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Image: The large crater Leibnitz of 245 km in diameter, is located on the far side of the moon. In the right corner, below image, Finsen crater 72 km in diameter. Right in the middle of the picture, Davisson crater 87 km in diameter. Credit: JAXA, NHK
Image: The shadows of the spectacular crater Tycho, detailed by the LRO. Diameter: 85 km with a central peak 2 km high Average depth: 4800 meters.
The crater Tycho is located in the southern hemisphere of the Moon and the child is a little more than a hundred million years.
The asteroid that hit the Moon at this point would be about 10 km in diameter. The shock caused a perfectly circular excavation to a depth of 4700 meters. The center of the crater is occupied by small mountains, the central peak, is over 2000 meters. The central peak was raised as a result of the sudden compression of the collision with the asteroid. It measures ten miles at its base. June 10, 2011, LRO has captured the rays of sun caressing the central peak of Tycho.
Image: The crater Clavius (right) is the third largest crater visible on the visible side. It is located in the rugged mountains south of the Moon, south of the crater Tycho. Because of its great size, Clavius can be detected with the naked eye. Clavius is one of the oldest formations on the surface of the moon, it was formed during the period Nectaria (-3 920 to -3 850 million years ago). It has a relatively smooth outer wall compared to its size, it is very worn and depth of 3500 meters above the surrounding soil. This crater of 30 000 square kilometers, was hailed other small young impact craters. In the center of Clavius, you will see not even the banks, because of the curvature of the Moon.