Re: Uniform gravitational Field
From: Uncle Al (UncleAl0_at_hate.spam.net)
Date: 12/20/04
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Date: Mon, 20 Dec 2004 16:02:52 +0000 (UTC)
Karl Poessl wrote:
>
> I'm been always interested in the Equivalence Principle beauty,
> and got the opinion that we have to try to deeply understand it.
Note that postulating the EP to model gravitation is entirely
unnecessary. Weitzenboek's affine gravitation (autoparallel paths)
contains the exact whole of metric gravitation General Relativity
(geodesic paths) - qualitative and quantitative - down to the last
decimal place. Affine gravitation is much harder to calculate.
Affine gravitation is much richer for allowing EP violation in several
circumstances.
Only one of them can be correct. Affine gravitation allows EP
violation by
1) Physically spinning test masses. Alas, they must be
relativistically spinning to have measurable violation ampltiude. The
two pairs of antiparallel spin 10,000 rpm fused silica gyro balls in
Gravity Probe-B show no hint of free falling along non-parallel paths
in hard vacuum vs. each other or their essentially non-spinning fused
silica housing.
2) Electomagnetically polarized test masses (magnets). Alas, the
active spin mass fractions are sub-ppm and gravitation only affects
mass. Spin Eotvos experiments by Eric Adleberger, Wei-Tou Ni, and
others give experimental null outputs to fractional parts-per-trillion
difference/average.
3) Opposite geometric parity test masses. No alas at all - 99.97+%
active mass and calculated theoretical extremal cases are trivial to
obtain. Three seminal parity Eotovs experiments are serially
proceeding in PR China using enantiomorphic single crystal quartz test
masses against each other (full parity experiment) and each against
amorphous fused silica (hemiparity experiments). See qz.pdf below.
> Before formulating General Relativity, Einstein tried to derive his
> results directly from this principle, but he could not get all of them.
>
> For a uniform gravitational field I think should be possible to derive
> all the correct result only using an uniform accelerated observer
> and the Equivalence Principle.
GR directly derives from the EP. Quadrupole tidal forces come later.
> I read many Books and papers on this subject and found that Rindler
> in his book Essential Relativity states (around page 120 of my edition)
> that it is not possible to do that. On the same subject I found a paper
> (E. Fabbri, European Journal of Physics 1994 pag 197) that states
> that this is possible and some calculation are done.
> There are few paper on this subject, but recently I found this one in
> the electronic archivie. http://uk.arxiv.org/abs/gr-qc/0409033
> I found this article rather interesting for both pedagogical and conceptual
> analysis. Did someone else read it?
Any treatment that derives metric gravitation from the EP must respect
affine gravitaton that wholly ignores the EP and neverhtheless arrives
at the same destinations.
-- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/qz.pdf
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