Реферат: Theories Of The Origin Of The Moon

Essay, Research Paper

The Moon is the only natural satellite of Earth. The distance from Earth

is about

384,400km with a diameter of 3476km and a mass of 7.35*1022kg. Through

history it has had many names: Called Luna by the Romans, Selene and

Artemis

by the Greeks. And of course, has been known through prehistoric times.

It is

the second brightest object in the sky after the Sun. Due to its size and

composition, the Moon is sometimes classified as a terrestrial "planet"

along with

Mercury, Venus, Earth and Mars.

Origin of the Moon

Before the modern age of space exploration, scientists had three major

theories for the origin of the moon: fission from the earth; formation in

earth

orbit; and formation far from earth. Then, in 1975, having studied moon

rocks

and close-up pictures of the moon, scientists proposed what has come to be

regarded as the most probable of the theories of formation, planetesimal

impact

or giant impact theory.

Formation by Fission from the Earth

The modern version of this theory proposes that the moon was spun off from

the earth when the earth was young and rotating rapidly on its axis. This

idea

gained support partly because the density of the moon is the same as that

of

the rocks just below the crust, or upper mantle, of the earth. A major

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