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From: aca@vaxine.UUCP (Alan Agostinelli)
Newsgroups: net.games.trivia
Subject: Re: more on the moon debate - (nf)
Message-ID: <291@vaxine.UUCP>
Date: Fri, 22-Jun-84 17:04:54 EDT
Article-I.D.: vaxine.291
Posted: Fri Jun 22 17:04:54 1984
Date-Received: Sat, 23-Jun-84 06:38:59 EDT
References: <1369@decwrl.UUCP> <4000003@ea.UUCP>
Organization: Automatix Inc., Billerica, MA
Lines: 18

I don't think that's quite right.  The reason that the moon doesn't rotate
isn't a mass anomoly, it's tides.  Picture a moon spinning on it's axis,
which is roughly parallel to the Earth's.  The gravitational field is some-
what stronger on the side of the moon closest to the Earth, somewhat weaker
on the opposite side (a small effect, but the *only* effect).  As the moon
rotates, mass must be "lifted" through this gradient on one side, and "lowered"
on the other.  This introduces stresses in the moons structure, and does work
on it (moonquakes).  This effect, over the eons, has turned the energy stored
in the moon's former rotation into random heat.

See Larry Niven's classic short story "Neutron Star" for a good discussion of
this topic.

				Alan Agostinelli
				Automatix, Inc.
				Billerica, Ma.
				...!allegra!linus!vaxine!aca