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From: jlg@lanl.ARPA (Jim Giles)
Newsgroups: net.physics
Subject: Re: The death of bogus physics
Message-ID: <875@lanl.ARPA>
Date: Mon, 24-Mar-86 08:34:27 EST
Article-I.D.: lanl.875
Posted: Mon Mar 24 08:34:27 1986
Date-Received: Wed, 26-Mar-86 06:41:40 EST
References: <12603@ucbvax.BERKELEY.EDU>
Reply-To: jlg@a.UUCP (Jim Giles)
Organization: Los Alamos National Laboratory
Lines: 44

In article <12603@ucbvax.BERKELEY.EDU> weemba@brahms.BERKELEY.EDU (Matthew P. Wiener) writes:
>Of all imaginable spaces ... in any kind of motion relatively to one
>another, there is none which we may look upon as privileged a priori....
>THE LAWS OF PHYSICS MUST BE OF SUCH A NATURE THAT THEY APPLY TO SYSTEMS
>OF REFERENCE IN ANY KIND OF MOTION.        [p 113]
>
...
>In a space which is free of gravitational fields we introduce a Galilean
>system of reference K(x,y,z,t) and also a system of co-ordinates
>K'(x',y',z',t') in uniform rotation relatively to K.  Let the origins of
>both systems, as well as their axes of Z, permanently coincide.  We
>shall show that for a space-time measurement in the system K' the above
>definition of the physical meaning of length and times cannot be maintained.
>[Because of special relativity, the circumference is measured by contracted
>rods and so seems longer, so the spatial geometry is not Euclidean.  Clocks
>too are our position dependent in K'.
[etc.]

All this is but to say that given sufficient mathematical sophistication
you can correctly work out what's going on in either coordinate system.  I
never doubted this.  But it still doesn't answer my original objection to
the Russell quote: given the frames K and K' - AT MOST one of them will be
able to spin up a gyroscope and observe NO precession.  In addition, the
frame which measures no precession on its gyroscopes will be fixed relative
to the distant stars to many significant figures of measurement (in the
neighborhood of Earth: within 0.1 arc seconds per year (MTW pp. 1119-
1121)).  To this extent, AT LEAST, there seems to be a prefered frame with
respect to rotation.

Now, I guess you are arguing that the coincident event of zero precession
locally and being fixed relative to the distant stars is 'merely a matter
of convenience'.  Well, I'm not buying it.  And neither did Einstein, who
spent considerable effort to determine why this might be so.  This is why
I brought Mach's principle into this discussion - which not only predicts
that there would be a 'prefered' frame, but gives a relativistic
explanation for the effect (it also predicts that any local variation
from the 'prefered' frame would be insignificant).

While it is certainly convenient to do one's calculations in a non-rotating
coordinate system, there also seems to be something physically significant
about such systems as well.

J. Giles
Los Alamos