Return to The Moon (idea)  How did the moon come into existence?
Analysis of data from the Lunar Prospector spacecraft in 1999
backs the long existing theory that the Moon masses were ripped
away from young Earth when an object the size of Mars ran into
it. Parallels in the mineral composition of Earth and the Moon
hint at a common origin. This similarity was already known. In
the past, some scientists have translated this into an
indication that Earth and the Moon had formed separately from
the same cloud of rocks and dust.  The recent Lunar Prospector
data shows however that the Moon has a small core that contains
less than 4% of the Moon's total mass. Earth's iron core
contains approximately 30% of the planet's mass. If Earth and
the Moon had merely formed from the same blur of rocks and dust,
the Moon would have a core comparable in proportion to Earth's,
scientists claim. A much more liable thought is that a large
body struck Earth, forcing a release of rocky matter from the
outer shell into orbit, whic