Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!mhuxm!mhuxf!mhuxi!mhuhk!mhuxt!houxm!whuxl!whuxlm!akgua!gatech!seismo!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.UUCP
Newsgroups: net.physics
Subject: Re: Coordinate frames in GR
Message-ID: <2175@brl-smoke.ARPA>
Date: Fri, 28-Mar-86 14:23:10 EST
Article-I.D.: brl-smok.2175
Posted: Fri Mar 28 14:23:10 1986
Date-Received: Tue, 1-Apr-86 06:53:46 EST
References: <438@batcomputer.TN.CORNELL.EDU> <1005@lanl.ARPA>
Reply-To: gwyn@brl.ARPA
Organization: Ballistic Research Lab (BRL)
Lines: 27

In article <1005@lanl.ARPA> jlg@a.UUCP (Jim Giles) writes:
>In article <438@batcomputer.TN.CORNELL.EDU> cpf@batcomputer.UUCP (Courtenay Footman) writes:
>>After several very bad articles on this subject, there have recently
>>been some very good ones, especially the one that noted that the Earth
>>does rotate, and that this is unambiguous because the geometry near the 
>>Earth is a Kerr geometry.  However, I feel that the lack of significance of 
>>coordinate frames should be stated forcefully.
>
>Bravo!!  I have been trying to get this point across for some time now.  I
>have confined my discussion to coordinate systems because it is easier to
>explain that way.  But the bottom line is still - 'The Earth DOES rotate,
>and this is UNAMBIGUOUS'.  There are some on the net who will take an
>overzealous remark by Bertrand Russell at face value over the whole of GR -
>and then accuse anyone who disagrees with them of ignorance!

The statement "the Earth rotates" is meaningless until you specify
with respect to what.  Nobody is arguing that the Earth is not
rotating with respect to the observed universe-environment.
The question is, is that different from the universe-environment
rotating with respect to the Earth?  (Is the latter question even
well-posed?)  You haven't answered that.  (Or if you have,
claiming that there is a difference, then either you don't fully
understand the depth of the question or else you claim something
that is not actually known at present.)

I do agree that people should be less insulting in technical
discussions.  This posting is not intended as an insult..