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Re: Moon's Spin



I think the composition of the moon suggests that it did not come from a
comet or an asteroid.
The assumption that the early planets were molten is another of those assump-
tions that make a story work. This assumption is probably a holdover from
the days prior to the discovery of radioactivity. If the planets formed
slowly they could have formed cold and solid, then radioactive decay would
have supplied the heat to allow the mobility for differentiation. It seems
quite clear, for example, that the heat with in the earth today was generated
by radioactive decay and that residual heat of formation makes only a minor
contribution. I find no compelling reason to accept either hot or cold
formation. I think the jury is still out & we need to keep an open mind.

I'm lost on the gravity part. Why should gravity have been different 4.5
billion years ago?