Help Understanding Michelson-Morley Exp: Explaining Fringe Difference

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Discussion Overview

The discussion revolves around the Michelson-Morley experiment and the ongoing inquiry into the small fringe differences observed in its results. Participants explore theoretical implications, experimental accuracy, and historical interpretations related to the experiment.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants suggest that the remaining fringe displacement is consistent with zero, considering experimental errors.
  • There is mention of improved accuracy in repeated Michelson-Morley experiments, with anticipation that significant displacement would generate excitement in the scientific community.
  • One participant references a paper discussing the Michelson-Morley experiment and its implications for local Lorentz symmetry.
  • Some participants propose a connection between the refractivity of the media and residual fringe shifts, though they note that these claims lack conclusive experimental support.
  • Concerns are raised about the validity of Dayton Miller's results, with suggestions that systematic movement of his apparatus may have influenced outcomes.
  • There is a discussion about the consistency of published results from various Michelson-Morley experiments with a locally preferred frame, though this is presented as a point of interest rather than proof.
  • Participants express skepticism regarding the support of claims by modern error-analysis techniques applied to both Michelson and Morley's data and Miller's data.
  • One participant expresses interest in seeing a paper that could clarify systematic errors in Miller's results using modern data analysis techniques.

Areas of Agreement / Disagreement

Participants express a range of views on the implications of the Michelson-Morley experiment and the interpretations of fringe shifts. There is no consensus on the validity of claims regarding refractivity or the reliability of Miller's results, indicating ongoing debate and uncertainty.

Contextual Notes

Limitations include unresolved questions about the influence of experimental conditions on results, the dependence of interpretations on definitions of absolute motion, and the varying estimates for the direction and magnitude of the Earth's motion relative to a locally preferred frame.

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I think I understand what the Michelson Morley expiroment proved, but I was wondering if we were ever able explained the small fringe difference that still exist?
 
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I think the remaining displacement was just consistent with zero, given the experimental errors.

AFAIK, the experiment has been repeated several times, most probably with improved accuracies. If the displacement is ever found to be significantly different from zero (i.e., if the expected experimental error is small compared to the measured displacement) everybody will be quite excited.
 
please have a look at a paper of mine om arxiv phyhsics education devoted to
the Michelson-Morley experiment.
brothenstein@gmail.com
 
Wizardsblade said:
I think I understand what the Michelson Morley expiroment proved, but I was wondering if we were ever able explained the small fringe difference that still exist?
M-M experiments probe the rotational invariance component of local Lorentz symmetry. Modern M-M experiments in which the light beams travel through vacuum all have vanishingly small residual fringe shifts. Some people have noted that there seems to be a connection between the refractivity of the media through which the light beams travel and the residual fringe shifts as a function of absolute motion: http://www.scieng.flinders.edu.au/cpes/people/cahill_r/processphysics.html , but such claims aren't really supported by any new and conclusive experiments...at least not yet.
 
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Aether said:
Some people have noted that there seems to be a connection between the refractivity of the media through which the light beams travel and the residual fringe shifts as a function of absolute motion: http://www.scieng.flinders.edu.au/cpes/people/cahill_r/processphysics.html , but such claims aren't really supported by any new and conclusive experiments...at least not yet.

Those claims are apparently not even supported by Michelson and Morley's data, based on modern error-analysis techniques:

http://groups.google.com/group/sci.physics.relativity/msg/7df6f9e77e4ee6c8
 
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jtbell said:
Those claims are apparently not even supported by Michelson and Morley's data, based on modern error-analysis techniques:
http://groups.google.com/group/sci.physics.relativity/msg/7df6f9e77e4ee6c8
"For the case of the original Michelson Morley experiment"...Cahill claims that there is much more evidence than just the original M-M experiment, especially the results of Dayton Miller, and including all other published results for M-M experiments conducted in gaseous media. At least AFAIK, there are no published results for a M-M experiment which are inconsistent with Cahill's claim. What seems strange to me is that there aren't any published results from an experiment that clearly and directly refutes Cahill's claim.
 
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Are people still citing Dayton Miller? I thought his results had been found to be due to systematic movement of his apparatus. Recall that he had situated it on a mountain top to get it out of any condensed ether associated with the earth, and as a result it was subject to micoroscopic oscillations drivien by the wind there.
 
selfAdjoint said:
Are people still citing Dayton Miller? I thought his results had been found to be due to systematic movement of his apparatus. Recall that he had situated it on a mountain top to get it out of any condensed ether associated with the earth, and as a result it was subject to micoroscopic oscillations drivien by the wind there.
I don't recall hearing anything about these microscopic oscillations before; I did read something about Einstein speculating openly that Miller's result was probably due to temperature gradients in the room where Miller's apparatus was operated, and Miller was insulted by that. Nevertheless, all published results for M-M experiments conducted in gaseous media seem to be consistent with the same locally preferred frame (except that several different investigators, all referring to more-or-less the same set of experimental data, have come up with different estimates for the direction and magnitude of the Earth's motion wrt that frame).

Try it, take the published results from any M-M experiment, and see if there aren't residual fringe shifts reported that are roughly proportional to the refractivity of the media and also consistent with Miller's/Cahill's locally preferred frame. I'm not saying that this is proof for a locally preferred frame, but it is interesting.
 
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  • #10
jtbell said:
Nor are they supported by Miller's data:
http://groups.google.com/group/sci.physics.relativity/msg/d17727952ff36efe
"I can show all this unambiguously using modern DSP and data analysis techniques. Note his systematic error can be cleanly and unambiguously separated from any possible real signal."

That would be interesting to see if/when he actually comes through with a paper that demonstrates this.
 

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