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Path: utzoo!watmath!csc
From: csc@watmath.UUCP (Computer Sci Club)
Newsgroups: net.games.trivia
Subject: Re: heavenly bodies
Message-ID: <7975@watmath.UUCP>
Date: Thu, 7-Jun-84 12:52:26 EDT
Article-I.D.: watmath.7975
Posted: Thu Jun  7 12:52:26 1984
Date-Received: Fri, 8-Jun-84 01:41:43 EDT
References: <99@tekigm.UUCP>
Organization: U of Waterloo, Ontario
Lines: 21

Yes the moon does rotate on its own axis.  However the moon always
keeps the same side facing toward the earth.  This leads to the
confusion you have experienced.

To illustrate take two plates and a table.  Put one plate in the center
to represent the earth.  Mark one edge of the other plate, this is the
moon.  Now revolve the moon about the earth without rotating it. (i.e.
move the marked plate in a circle around the unmarked plate while making
sure the marked edge of the plate always points to the same edge of the
table)  You will note that the moon does not always have the same side
facing the earth. Next revolve the moon about the earth keeping the marked
edge facing the earth.  You will note that as you revolve the plate once
about the earth, it will rotate on its axis (realative to the table) once.
This is the what the moon does.  In order to keep the same side facing the
earth it must (relative to the stars) rotate once on its axis for each
revolution around the earth.

Hope I have not confused things even more.

                                                   William Hughes