Moon | ||||
Satellites of planets | Automatic translation | Updated June 01, 2013 | ||
When we look at the sky, the stars form figures do not change over the centuries. | With the exception of Mercury and Venus, all the planets in the solar system have moons qualified moons. Image: photograph of a bright moon, taken in Caen - France in the summer of 2009. | |||
Moon | ||||
There are more than 160 moons in the solar system, but the Moon exceptionally large relative to its planet, it is a great satellite, its diameter is 3 474 km while that of the Earth is 12,756 km, the Moon that is smaller than 4 times the Earth. Although the Moon is not the largest in the solar system, its relationship to the planet is the largest (27% compared to the Earth), Ganymede (3.7% compared to Jupiter), Titan (4.3 % by Saturn), Callisto (3.4% compared to Jupiter) and Io (2.5% compared to Jupiter). The Earth-Moon configuration is unique in the solar system outside the couple Pluto-Charon (52%). The Moon is the only celestial body on which the man is gone, and yet it is not so friendly as you might think. There is absolutely no air, so you need a pressure suit any leakiness of the combination exposes astronauts to deadly empty. It is also a world of silence, the sound can not be transported unless the use of radio transmitters and headphones. | As there is no atmosphere, sunlight is not filtered and then the sky is always black. In addition there is no color, the landscape is sad, it is the same everywhere in a more or less monotonous gray tone. Temperatures are extremely inhospitable, the transition from hot to cold is especially brutal, 132°C during the day to -151°C at night. And finally the absence of a magnetic field passes deadly solar radiation. Many meteorites collide with the lunar surface at high speed without being slowed down, for 4 billion years, they spray the moon rock, creating over a layer of fine dust, regolith. The dust is so fine that it presents a danger, it sticks on the combinations and on the instruments and would be a big problem if we were to live. | |||
Origin | ||||
The Moon with one L capital letter, always has was a center of major interest for the man. The origin of the Moon is the object of a scientific debate. Image: This photo of December 2010, is a mosaic of 1300 images from the visible face of the Moon, taken by the lunar probe LRO. | ||||
Both most brilliant celestial bodies | ||||
The most brilliant both celestial bodies of the night-sky seemed to touch in the evening of May 19th, 2007, the Moon and the planet Venus were visible in the same part of the sky, and at the time of their biggest nearness were separated only from a degree of bow. The conjunction appears here such as it was visible since the neighborhood of the city of Quebec in Canada. Venus is situated in the western South of the Moon. | The distance which really separates these two celestial bodies was about 250 million kilometers and this visible nearness, called a conjunction, is only an illusion of perspective. Although the Moon so exceeds Venus every month, a visible passage so moved closer in the evening is relatively rare. Image: Photo of Venus and the distance of the Moon illuminated by the Sun in the foreground. | |||
A theory which reminds coupling of two living cells | ||||
The various theories on the origin of the Moon in competition up to the edge of the spatial era were worsened by the results of the analyses of the lunar rocks. | Let us imagine that at the beginning of the creation of the Earth, a planet very big of the size of Mars (half of the size of the Earth), him too differentiated (metal nucleus, coat) which under a particular angle of impact and a relative speed came to collide the Earth. This collision provokes the fusion of both metal nuclei, whereas the materials of the coat of both objects of the solar system are ejected but remain bound to the Earth by the force of gravity. | Most of its materials are slowly going to gather together in what is going to become our Moon. All this takes place at the very beginning of the history of the Earth, which kept it no track. Nevertheless, the numeric simulations succeed in representing well enough the stages. On the other hand, this hypothesis is contradictory not at all with that we know at present about the Moon. |
Theia, hypothetical planet | ||||
The simulations of the formation of the solar system continue to give more weight to the above scenario for the formation of Moon. | Exploration Agency (JAXA) was launched and the mission Selenological Engineering Explorer (Selene), later renamed Kaguya. Scientists are inclined to this theory as compared to moons of other planets in the solar system, ours is much more larger than average and its orbital distance lower than other moons. What makes that our moon can not have been captured in from nearby, like the other moons. The most probable theory is that Theia, before the collision, was follow an orbit similar to Earth at Lagrange point A Lagrange point (denoted Li), or libration point is a position in space where the gravitational fields of two bodies in orbit around each other, and substantial masses are combined so provide a balance to a third body of negligible mass, as the relative positions of the three bodies to be fixed. Earth-Sun. Image: simulated impact of the 2 objects, there are 4.533 billion years or about 34 million years after the formation of Earth. | |||
Craters of the Moon | ||||
The hidden side of the Moon is perpetually invisible from the Earth, so it is impossible to take photographs of the face without the use of space probes. Curiously, the hidden face is different from the visible face as well in terms of its average altitude than the rate of cratering. Regularly, images and spectacular videos of the surface of the Moon and especially its dark side, we are sent by U.S. probes and Japanese probes. Clementine mission had not seen the full moon, but the probe Kaguya-Selene the most important lunar mission since the Apollo program, launched in 2007, has sent us photographs of a high precision in the order of 10 meters per pixel. | Which helped detect new small craters and thus to refine the measurement of the lunar cratering rate land. Image: the large crater Leibnitz 245 km diameter, located on the face of the Moon. In the right corner, below the image, the crater Finsen 72 km diameter. | |||
Water in small quantities on the Moon | ||||
The French and American researchers have discovered water, small quantities of course but almost everywhere on the surface of the Moon, at latitudes above 10 degrees. This result has been published in the journal Science on 25/09/2009. | The U.S. probe LCross (Lunar Crater Observation and Sensing Satellite) that hit the moon on friday 9 October 2009 in 11 30 hours UT, has enabled scientists to detect the presence water at south pole of the Moon. Image: The discovery of water on the moon is confirmed by 2 instruments: instrument M3 Indian Chandrayaan 1 mission and instrument VIMS of the Cassini-Huygens mission (ESA / NASA). | |||
Mare Orientale | ||||
This gigantic crater drawn on the surface of the Moon is called Mare Orientale is one of the most impressive lunar crater basins, by its large size. | Early astronomers thought that these regions could indeed be vast expanses of water. Image: mosaic of images of the ringed structure of the large lunar impact basin Mare East. Credit: NASA / GSFC / Arizona State Univ. / Lunar Reconnaissance Orbiter | |||
Influence of the Moon | ||||
The moon has a definite influence on the lives of Earth, the gravitational influence is due to its proximity. The tides known, is due to the influence of the moon on the oceans. It causes a rise followed a drop of water level in waterfront in cycles of about 12 hours. The tide is produced by the motion of revolution around the Moon Earth. The moon's gravitational effect on Earth's oceans and seas, causes a local rise in water level on the surface of the Earth toward the Moon but also on the side opposite the moon. | Seismic activity, the magma of the mantle, now under the solid crust, also suffers because of its viscous state movements, corresponding to the passage of the satellite. |