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Stoat
United Kingdom
863 Posts |
 Posted - 13 Jan 2009 : 05:40:48
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I don't buy it for the Earth, The proto earth had to lose a lot of angular momentum. It would do it in two goes, first it spins off an equatorial sheet of half its mass along the line of the equator. It carries on collapsing inwards and then spins off a gobbet of material, of about one tenth of its mass. This would be Mars. There would also be a string of molten junk, which becomes our moon.
Now Mars has for certain been hit by something big, and that something wasn't travelling fast enough to tear the planet apart. Mars being smaller than the earth, cools more quickly but even if a number of these bits of gobbet went into orbit around it, and then fell in later to impact the planet, the interior should still have been plastic enough to let the gobbet core and the planet core combine into one. Yet the core of Mars looks very much like two cores. It's twisted round almost ninety degrees in its orbit.
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earth's core - one or two?
