Earth acquiring the Moon
Name: Andre Vernon
What is the leading theory on how the Earth acquired the Moon?
The current leading theory is that both the Earth and Moon formed as proto-
planets orbiting at the same distance from the Sun. This early stage in the
development of the Solar System occurred about 4.5 billion years ago.
Around 1 billion years later, the Moon was captured by the Earth's gravity
and began orbiting the Earth. The evidence for this is that catastrophic
changes occurred on the surfaces of both the Earth and Moon at this time:
the Earth's surface melted, and the maria were formed on the Moon. These
changes were the result of enormous tidal forces generated as the Moon
passed close to the Earth's Roche limit.
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Update: June 2012