First historical experiment disproving Ritz emission theory?

In summary: This seems to be contradicted by the Sagnac effect, in which the two light sources are compared without any intervening medium.The Sagnac effect is a result of the comparison of light sources that are not in contact with each other, and therefore does not involve any medium. It is not contradicted by the Ewald-Oseen extinction theory.
  • #1
bcrowell
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Ritz proposed in 1908 that SR was wrong, and that the speed of light would depend on the speed of the source according to Galilean addition of velocities, c+v. The review linked to from PF's sticky on the experimental basis of SR has a nice section on this: http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html#moving-source_tests

These results are typically described in terms of a limit on k, where the speed of light is c+kv, k=0 being SR and k=1 being the Ritz theory.

Early tests such as de Sitter's in 1913 http://en.wikipedia.org/wiki/De_Sitter_double_star_experiment were later realized to be problematic because of optical extinction. The earliest test they list that disproves k=1 and is not subject to optical extinction or other issues is a pair of experiments in 1964.

It seems impossible to believe that the Ritz theory was really viable until 1964. Of course nobody believed it by then, and it was indirectly inconsistent with a gazillion other experiments, but was there really no direct disproof of k=1 until 1964? Were the early tests such as de Sitter's sufficient to falsify k=1, even given extinction? (De Sitter claimed k<.002, but he didn't consider extinction.) Historically, what was the first direct test that ruled out the Ritz theory?
 
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  • #2
Good question. I don't think I've seen any particular experimental test acknowledged in the literature which definitely rules out the Ritz theory. As you mention, it's typically reasoned away on the basis of additive velocities, De Sitter's reasoning (which I find pretty unconvincing) and lack of compliance with the Oseen extinction theory (which I find even less convincing).

However, a full analysis of the Sagnac experiments (1913?) and all related ones including the Michelson-Miller experiment a couple of decades later very clearly shows that emission theories do not apply in the case where two light sources having different paths to the detector are compared. If the Ritz theory were correct no shift in phase of the 2 signals would occur, right?
 
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  • #3
PhilDSP said:
Good question. I don't think I've seen any particular experimental test acknowledged in the literature which definitely rules out the Ritz theory.

No, please take a more careful look at what I wrote in #1, and read the edu-observatory.org link. It was definitely directly disproved by experiments in 1964. The only question is whether it was directly disproved before then.

PhilDSP said:
As you mention, it's typically reasoned away on the basis of additive velocities, De Sitter's reasoning (which I find pretty unconvincing) and lack of compliance with the Oseen extinction theory (which I find even less convincing).

No, that's not what I said.
 
  • #4
bcrowell said:
Historically, what was the first direct test that ruled out the Ritz theory?

Ritz's original theory doesn't involve extinction effects, and therefore it was conclusively ruled out by DeSitter's double stars and the Sagnac effect, both in 1913.

As regards the modified "extinction emission theory" (which wasn't discussed before the 1960ies), they were also conclusively ruled out after 1964 by a lot of experiments in vacuum (Sagnac type or with moving sources) and Brecher's modified version of DeSitter's experiments.

However, if there were also relevant experiments before 1964 which were overlooked by Fox, I don't know.

* Fox, J. G. (1962), "Experimental Evidence for the Second Postulate of Special Relativity", American Journal of Physics, Volume 30, Issue 4, pp. 297-300
* Fox, J. G. (1965), "Evidence Against Emission Theories", American Journal of Physics 33 (1): 1–17
* Fox, J. G. (1967), "Constancy of the Velocity of Light," J. Opt. Soc. Am. 57, 967-968
http://mysite.verizon.net/cephalobus_alienus/papers/Fox_1967.pdf

Regards,
 
  • #5
Histspec said:
Ritz's original theory doesn't involve extinction effects, and therefore it was conclusively ruled out by DeSitter's double stars and the Sagnac effect, both in 1913.

Sorry, but I don't follow you here. Doesn't extinction exist regardless of whether you believe in SR or an emission theory?

But it sounds like a good answer to my original question is simply that the Sagnac effect disproves emission theories, since the Sagnac effect occurs in vacuum, and you don't get extinction in a vacuum.

I guess it's odd, though, that the edu-observatory.org page doesn't even mention the Sagnac effect in its discussion of moving source tests. Maybe that's because the waters are muddied by the existence of multiple versions of the emission theory that make different statements about what happens in reflection: http://en.wikipedia.org/wiki/Emission_theory#History

Thanks!

[EDIT] Oh, I see, the Fox 1967 paper says that in Ritz's original formulation, he assumed that scattering would leave the velocity of the light unaffected. That seems bizarre to me, but I suppose there was never really any plausible set of physical mechanisms for the Ritz theory anyway.
 
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  • #6
bcrowell said:
But it sounds like a good answer to my original question is simply that the Sagnac effect disproves emission theories, since the Sagnac effect occurs in vacuum, and you don't get extinction in a vacuum.

It sounds like the Wikipedia article compounds some confusion about extinction. According to the Ewald-Oseen extinction theory, incident radiation suffers extinction from any charge that is relatively free to move in response to the radiation within the specified spatial area regardless of whether its embedded in a vacuum or media (including the charges in the detector). Astronomers though, might be most focused on secondary extinction occurring in intervening matter while the light is in transit.

But since the paths of light are circular in the Sagnac experiment (the mirrors are symmetrically situated), any possible extinction effects from the mirrors should cancel out.
 
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  • #7
PhilDSP said:
[..]
However, a full analysis of the Sagnac experiments (1913?) and all related ones including the Michelson-Miller experiment a couple of decades later very clearly shows that emission theories do not apply in the case where two light sources having different paths to the detector are compared. If the Ritz theory were correct no shift in phase of the 2 signals would occur, right?

Yes I would think so. But we can trace the disprove of ballistic emission theories to much earlier in time, as I think Einstein understood before writing his 1905 paper. What many people (incl. Ritz?) seem to overlook is the Fizeau experiment that was meant to test the Fresnel drag coefficient. Not only the results were consistent with Fresnel's theory, at the same time the results rejected the whole class of ballistic emission theories.

See also http://en.wikipedia.org/wiki/Fizeau_experiment

Cheers,
Harald
 
  • #8
I have a few questions regarding this topic:

1) I would like to know a little bit more about these gazillion mentioned by bcrowell:
bcrowell said:
... and it was indirectly inconsistent with a gazillion other experiments, ...
What are some examples of these indirect experiments?

2) I would also be interrested in the most recent experiences disproving the Ritz emission theory.

3) Curious also about te most precise experiences disproving the Ritz theory.

4) Finally, are there some recent experiences putting some opposite evidence, or some remaining doubts?

Thanks,

Michel
 
  • #9
lalbatros said:
I have a few questions regarding this topic:

1) I would like to know a little bit more about these gazillion mentioned by bcrowell:

What are some examples of these indirect experiments?
One example was mentioned in the foregoing post. :wink:
[..]
3) Curious also about te most precise experiences disproving the Ritz theory. [..]
Perhaps ring laser gyroscopes?
- http://en.wikipedia.org/wiki/Sagnac_effect
 

Related to First historical experiment disproving Ritz emission theory?

1. What is the Ritz emission theory?

The Ritz emission theory, also known as the Ritz-Weyl emission theory, was a theory proposed in the early 20th century to explain the emission of light from atoms. It suggested that atoms emit light in discrete packets or quanta, rather than in a continuous stream.

2. What was the first historical experiment disproving the Ritz emission theory?

The first historical experiment to disprove the Ritz emission theory was conducted by Robert Andrews Millikan in 1916. He observed the emission of light from a heated tungsten filament and found that the intensity of the emitted light did not change in discrete steps, as predicted by the Ritz theory, but rather in a continuous manner.

3. How did the experiment disprove the Ritz emission theory?

Millikan's experiment showed that the intensity of the emitted light changed smoothly and continuously, rather than in discrete steps as predicted by the Ritz theory. This indicated that the energy of the emitted light was not quantized, as proposed by the theory.

4. What impact did the first historical experiment have on the Ritz emission theory?

The first historical experiment disproving the Ritz emission theory was a significant blow to the theory, as it provided strong evidence against the idea of quantized energy levels in atoms. This paved the way for the development of quantum mechanics, which revolutionized our understanding of the atomic world.

5. Are there any modern theories that incorporate the ideas of the Ritz emission theory?

While the Ritz emission theory was ultimately disproven, its ideas of quantized energy levels and discrete packets of light still have relevance in modern quantum mechanics. The Bohr model of the atom, which was developed shortly after the Ritz theory, also incorporated the concept of quantized energy levels and played a crucial role in the development of quantum mechanics.

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