Реферат: Theories Of The Origin Of The Moon

with this theory is that the angular momentum of the earth, in order to

achieve

rotational instability, would have to have been much greater than the

angular

momentum of the present earth-moon system.

Formation in Orbit Near the Earth

This theory proposes that the earth and moon, and all other bodies of the

solar

system, condensed independently out of the huge cloud of cold gases and

solid

particles that constituted the primordial solar nebula. Much of this

material

finally collected at the center to form the sun.

Formation Far from Earth

According to this theory, independent formation of the earth and moon, as

in

the above theory, is assumed; but the moon is supposed to have formed at a

different place in the solar system, far from earth. The orbits of the

earth and

moon then, it is surmised, carried them near each other so that the moon

was

pulled into permanent orbit about the earth.

Planetesimal Impact

First published in 1975, this theory proposes that early in the earth’s

history,

well over 4 billion years ago, the earth was struck by a large body called

a

planetesimal, about the size of Mars. The catastrophic impact blasted

portions