Help Understanding Michelson-Morley Exp: Explaining Fringe Difference

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In summary: 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.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
  • #1
Wizardsblade
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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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  • #2
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.
 
  • #3
please have a look at a paper of mine om arxiv phyhsics education devoted to
the Michelson-Morley experiment.
brothenstein@gmail.com
 
  • #4
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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  • #5
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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  • #6
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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  • #7
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.
 
  • #8
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:
"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.
 

1. What is the Michelson-Morley Experiment?

The Michelson-Morley Experiment was a scientific experiment conducted in the late 19th century by Albert Michelson and Edward Morley. It aimed to detect the presence of the hypothetical "ether" that was believed to be the medium through which light waves traveled.

2. How did the Michelson-Morley Experiment work?

The experiment involved splitting a beam of light into two perpendicular beams and then recombining them. The two beams would travel different distances, depending on the direction of the Earth's movement through the ether. However, the experiment showed that there was no difference in the time it took for the beams to travel, indicating that there was no ether present.

3. What were the results of the Michelson-Morley Experiment?

The results of the experiment were unexpected and groundbreaking. They showed that the speed of light is constant, regardless of the direction of the Earth's movement through the hypothetical ether. This contradicted the prevailing theory of the time, which stated that the speed of light would vary depending on the direction of movement.

4. What impact did the Michelson-Morley Experiment have on science?

The Michelson-Morley Experiment was a pivotal moment in the history of science, as it paved the way for Albert Einstein's theory of relativity. It also challenged the traditional beliefs about the nature of light and the concept of a stationary ether. The experiment's results led to a paradigm shift in physics and laid the foundation for future scientific discoveries.

5. Why is the Michelson-Morley Experiment still relevant today?

The Michelson-Morley Experiment remains relevant today as it continues to be a fundamental experiment in the field of physics. Its results have been replicated and confirmed by numerous experiments, further solidifying our understanding of the constant speed of light and the absence of an ether. The experiment also serves as a reminder of the importance of questioning traditional beliefs and continuously pushing the boundaries of scientific knowledge.

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