Data from Wikipedia and NASA (C)
The Moon is the only natural satellite of the Earth.
Motion of the Moon
The face of
the Moon turned in opposite direction to the Earth comes called dark face,
whose meant here it is meant like disowned and hidden; one refers also to black
out of the radio communications, that it happens when a spaces probe them moves
behind the far face. The greater part of the far face cannot be seen from the
Earth, because the revolution of the moon around the earth and the rotation
around its axis has the same period. A small portion can be seen thanks to the libration, that it renders irregular the motion of rotation
of the Moon. In the complex from the earth it is visible approximately 59% of
the lunar surface. The near face of the Moon is covered approximately by 30 000
craters (counting those with a diameter at least
The Moon and the celestial sphere
The Moon completes a complete orbit of the celestial sphere approximately every 27 days and 7 hours, but the observer on the earth counts approximately 29,5 days between a new moon and the successive one, because of the contemporary movement of Earth revolution. In the course of an hour distance it moves in the sky approximately of 0.5 degree, its angular dimension. The Moon always remains in a region of the sky called zodiac, than it extends approximately 8 degrees over and under the ecliptic.
The origins of the Moon are in the center of a scientific debate. The most credited theory is that it has formed because of the collision of an asteroid with dimensions similar to those of Mars with the Earth when this last one was still warm, in the first phase of its formation (such asteroid is called Theia). The material gushed from the impact remained in orbit around to the Earth and for effect of the gravitational force it gathered forming the Moon. It is the Theory of the Giant Impact. A confirmation of this thesis derives from the fact that the composition of the Moon is almost identical to that one of the Earth’s cape without the lighter elements, evaporates for the lack of an atmosphere and the gravitational force necessary in order to withhold them. Moreover, the inclination of the orbit of the Moon rather renders the theories improbable if the Moon was formed with to the Earth or was captured later on.
period of rotation of the Moon is exactly equal to its orbital period, we sees always the same face of the Moon, revolt towards the
Earth. This synchrony is the result of the gravitational clutch that has slowed
down the rotation of the Moon in its history. Because of these forces, said
also tide forces, also the rotation of the Earth comes gradually slowed down,
and the Moon goes away slowly from the Earth while the rotational moment of
this last one comes transferred at the orbital moment of the Moon. The
gravitational attraction that the Moon exercises on the Earth is the cause of
the tides of the sea. The variations of the tide are synchronized with the
orbit of the Moon around the Earth. The Earth and the Moon orbit round to a
common center of mass, that
distance of approximately
More than 4,5 billions than years ago, the surface of the Moon was a liquid magma ocean. The scientists think that one of the components of lunar cliffs (said KREEP, acronym of the English expression K (potassio), Rare Earth Elements (rare-earths), and P (phosphorus), represent the last rest of the original magma. The KREEP is composed from that that the scientists call "incompatible elements": they are elements that cannot enter to make part of the structures of crystals, and that therefore they are leaves unusable on the surface of the magma. For the investigators, the KREEP is a useful marker, in order to determine the history of the lunar volcanism and to trace the chronology of the impacts from celestial comet and other objects. The lunar crust is composed from a variety of primary elements: uranio, thorium, potassio, oxygen, silicon, magnesium, iron, titanium, soccer, aluminum and hydrogen. When it comes bombed from the cosmic beams, every element reemits in the space a its own particular radiation, under shape of gamma beams. Some elements, like uranium, thorium and potassium, are radioactive and emit gamma beams. Which is their cause, the range beams emitted from every element are various, and a spectrometer can distinguish them, and exactly in this way it has been possible to discover of the existence. A total map of the Moon of abundance of these elements, still has not been realized. The Moon for great part of its ancient history has been bombed from comets and asteroids, many rich of water. The energy of the solar light divides the greater part of this water in its constituent elements, hydrogen and oxygen, of which the greater part it is dispersed immediately in the space. It has been but assumed that meaningful amount of water can remain on the Moon, on the surface, or inglobate in the crust. The datas of the probe Clementine suggested that in the zones permanently in shadow of the crust can be found small iced zones, than do not have occasion to melt itself. Even if these zones are probably small, the water amount total could be remarkable: a billion of cubic meters, as the volume of the lake Erie. Some water molecules, moreover, could directly be landed to the surface and be remained caught within craters of the lunar poles. Because of the modest inclination of the lunar rotation axis (only 1,5°), some of deepest polar craters never do not receive light from the Sun, always remaining in shadow. It is in these craters that the scientists expect to find water, if present. If it were found, the water (under ice shape) can be extracted and therefore divided in hydrogen and oxygen from generators to solar energy. The presence of usable water on the Moon could be an important factor in possible rendering its colonization, because the transport from the Earth would be extremely expensive. The cliffs of the Moon collected from the astronauts, all coming from from the equatorial zone, did not introduce some water trace. Not even the more recent probe Lunar Prospector, or other searches, has found some evidence of water, ice or vapor of water.
magnetic field of the Moon is much low to comparison of that earthling. It is
believed that a part of it is intrinsic (as in a part of the lunar crust called
Sirsalis Rhyme), while the collisions with other
celestial bodies can have some formed an other part.
In effects, one of the issues still opened in planetary science is if a body without
air, like the Moon, can obtain a magnetic field from impacts with comets and
asteroids. The measurements of the magnetic field can give to moreover
information on the dimension and the electrical conductivity of the lunar nucleus,
supplying therefore datas for a better theory of the
origin of the Moon. As an example, if the nucleus contained a greater
proportion of magnetic elements (like the iron) regarding that earthling, the
theory of the birth for impact would lose credit (even if could exist
explanations alternatives for this fact). Over all the lunar crust spreads a external powder cliff layer, call regolite.
The crust and the regolite are distributed in
irregular way, one with one thickness from 60 to
History of the lunar exploration
face, always opposite to the Earth, of the Moon came observed for the first