Saturday, December 13, 2008

If We Had No Moon

Did you know the moon takes 27 days to rotate once? That the moon is unsually large - a freak in our Solar System - since it is almost a quarter the size of Earth? This is a fascinating article.
clipped from astrobio.net
If the time of Earth’s existence was condensed into a 24-hour clock, the moon formation event occurred just 10 minutes after the Earth was born. The Earth formed 4.56 billion years ago, and the Moon formed about 30 million years later. At that time, the Earth was a magma ocean. An impactor about the size of Mars struck the Earth at an oblique angle, and removed some of the magmatic mantle. This mantle was put in orbit around the Earth, together with some of the debris from the impactor itself, and this material eventually formed the Moon.
By exploring the Moon, we also can get clues on how the Earth has evolved. We can study processes on the Moon that have also shaped the Earth, like volcanism and tectonics.
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