Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 beta 3/9/83; site vaxine.UUCP Path: utzoo!linus!vaxine!aca 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