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From: desj@brahms (David desJardins)
Newsgroups: sci.physics
Subject: Re: background radiation
Message-ID: <309@cartan.Berkeley.EDU>
Date: Sat, 15-Nov-86 20:31:26 EST
Article-I.D.: cartan.309
Posted: Sat Nov 15 20:31:26 1986
Date-Received: Sun, 16-Nov-86 02:26:00 EST
References: <1388@trwrb.UUCP> <546@mcgill-vision.UUCP> <1167@cit-vax.Caltech.Edu> <3422@sdcrdcf.UUCP> <5397@brl-smoke.ARPA>
Sender: daemon@cartan.Berkeley.EDU
Reply-To: desj@brahms (David desJardins)
Organization: Math Dept. UC Berkeley
Lines: 42

In article <5397@brl-smoke.ARPA> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>>...  In fact, there is an
>>observed doppler shift in the background radiation as seen from earth.
>>This has been used to get a fairly good estimate of the real velocity
>>of the earth, sun, milky way, etc. with respect to the rest of the universe
>
>This situation is pretty funny to the skeptic, which I am,
>having witnessed an incredible number of ideas representing
>"current consensus of the physics community" fade away
>into oblivion during the last 20 years:
>
>The original interpretation of the "isotropic background
>black-body radiation" as being cosmic rather than local
>was largely due to its isotropic nature (so far as had
>been measured initially).
>
>Now that the phenomenon is taken for granted to be cosmic
>and not local, the anisotropy that newer measurements have
>turned up is taken to indicate absolute motion with
>respect to the cosmos.

   This is really silly.  The theory clearly predicts a small anisotropy
due to the motion of the Earth around the Sun and the Sun around the Milky
Way (and perhaps larger-scale motions as well).  This has been obvious to
physicists ever since background blackbody radiation has been discovered.
Now that we have instruments sensitive enough to measure this small an-
isotropy, and to confirm that it is of the right order of magnitude to
conform to predictions, what on Earth is wrong with using it to measure
the motion which causes it?

   I would have thought that you would understand the small amount of GR
necessary to understand why these observations fit the theory perfectly.
But apparently not.  I suppose it is easy to be a skeptic if you don't
bother to understand the ideas you are being skeptical about.

   -- David desJardins

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