"David Park" wrote in message ink.net...
(To Moderator: Sorry for reposting. I wanted to correct a spelling error.)

" If two inertial observers exchange light signals they will observe the
same Doppler effect."

This is sometimes used in special relativity derivations. I don't doubt it
but I wondered if there has ever been an experiment to directly test this
and perhaps put an upper limit on any deviation. What experimental evidence
could I cite for it?

(I'm not talking about symmetry of Doppler broadened spectral lines. I'm
asking about the much simpler question of two observers in relative motion
exchanging light signals and measuring the Doppler shifts.)

David Park

http://home.earthlink.net/~djmp/

The usual perception of the Doppler effect is based simply on the
basic logic of the Doppler shift (like counting of wavecrests) and the
(postulate of) constancy of c in SR. Most people take this to be
sufficient for their needs and the issue of deviations does not seem
to have been considered in the peer-reviewed literature. Note that a
spectral deviation would be considered as measurement error or noise
if did not show up consistently, so we would presumably want to
examine the case of systematic deviations if any. Such a deviation
could mean viewed as (a) a systematic error in our distance/velocity
scales in the context where the deviation was observed, (b) a
systematic error in our theories predicting the distance/velocity
distributions in that context, or (c) a systematic spectrometric
error. Cases (a) and (b) are already involved in the contexts of the
cosmological acceleration, the galactic rotation profile and the
Pioneer anomalous acceleration problems.

In gr-qc/0005014, Section II, I examined case (c) by applying the
usual partial differential error sensitivity analysis to spectrometry,
with respect to the local reference frame units of scale. I withdrew
it after acceptance by the editor of a peer-reviewed journal because I
was not satisfied with my articulation, and because it leads to
speculative physics out of step with mainstream thinking - the 3 step
result looks identical to an apparent linear expansion or contraction
of the universe relative to the observer with the erroneous
spectrometer, replete with an acceleration in the exact ratio as the
cosmological. So please be warned it's unpublished in a peer-reviewed
journal and got into arxiv.org before endorsements, so I can't even
clean it up and fully deserve all the flames I've got.


-prasad.