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Thim experiment: Doppler expected or not?

  1. Feb 24, 2009 #1
    Hello,

    This paper presents an experimental setup and claims that Special Relativity would predict a second order Doppler shift:

    http://www.atomicprecision.com/blog/wp-filez/Thim%20-%20Absence%20of%20the%20relativistic%20Doppler%20effect%20...%20.pdf [Broken]

    Since the emitter and receiver have no relative motion, I do not think SR would predict a shift.
    If I am right, where is the flaw in this paper?

    Thanks
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 24, 2009 #2

    Dale

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    The transverse Doppler effect is the same as time dilation, and it has been experimentally validated both http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html#Doppler_shift". I haven't looked at the setup in detail, but I suspect that the problem is one of instrumentation. With microwave frequencies you would need to be at a considerable fraction of c before you could detect the phase shift, higher frequency measurement are more accurate than this microwave frequency test.
     
    Last edited by a moderator: Apr 24, 2017
  4. Feb 24, 2009 #3

    Ich

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    Last edited by a moderator: Apr 24, 2017
  5. Feb 24, 2009 #4

    Vanadium 50

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    The transverse Doppler effect was first measured in 1938 by Ives and Stilwell, and repeated many times since then. If Thim doesn't see it, it's probably due to his incompetence as an experimenter - a quality also brought out by the complete lack of a discussion on experimental uncertainties and a near complete lack of discussion on sensitivity and controls.

    Furthermore, the paper was posted on a crackpot web site. That alone should have tipped you off.
     
  6. Feb 24, 2009 #5

    Vanadium 50

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    Last edited by a moderator: Apr 24, 2017
  7. Feb 24, 2009 #6
    It is right that I asked this question already before, but I am still interrested to understand this experiment further and show the conclusion is wrong.

    I would like to conclude in another way than simply saying the obvious: no relative motion implies no shift. I must also say that I could not understand the explanations by Thim.

    I even did not fully understand the experimental side.
    For example the resonators installed on each disks, these would complicate a pure electromagnetic analysis of this system. However, is it not possible to analyse a simpler but conceptually equivalent system? An equivalent system that would have a cylindrical symmetry. In such a system, what would be the difference between a rotating conductor and a non-rotating conductor? Would that not indicate that the complication of the setup has led to the wrong conclusion?

    More basically, I do not even understand the use done of the Lorentz transformation in the paper.
    And since the Lorentz transformation is intimately linked to the Maxwell's equations describing the same system, I also expect a mistake in the explanations by Thim. It is also remarkable that Thim did not analyze what the Maxwell's equations would predict.

    I would appreciate any clarification.

    Thanks
     
  8. Feb 25, 2009 #7

    Ich

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    Take a transversally moving mirror, and reflect a perpendicular laser beam from it. What frequency and direction has the reflected beam? Transform to the mirror's rest frame, invert the beam there, and transform back. That's a simpler version of what Thim has done.

    Thim has a very poor understanding of relativity, and is additionally hampered by his cranky attitude.
    Example:
    Now, that's an analysis.
     
  9. Feb 25, 2009 #8
    Thanks for your reply, Ich.

    Without a good a understanding I can only try to guess how to understand the Thim's experiment.
    It is indeed interresting to try to imagine a simpler but equivalent experiment so as to make its meaning clearer.
    Unfortunately, I think this should not be an equivalent experiment:

    With such a moving mirror, the path length should increase with time.
    This is equivalent to an increasing distance between emitter and detector.
    Therefore in this case there should even be a first order Doppler effect.
    Missing a first order Doppler effect would invalidate much more than special relativity!
    But it is probably possible to built a first order Doppler experiement with fixed emitter and detector.

    On the contrary, I think that it is impossible to built any experiment with fixed emitter and detector that should only show a second order Doppler.
    But can we prove this?

    (with a moving emitter, this should be possible, maybe in a Mossbauer experiement for example)
     
  10. Feb 25, 2009 #9

    Ich

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    Ah no, the mirror is thought to be moving sideways, maybe rotating. The beam is coming in always perpendicular from the same distance.
     
  11. Feb 25, 2009 #10
    Thanks for the clarification, Ich.

    In this case, it is clear that there should be no Doppler effect.
    A rotating (perfect) conductor remains a (perfect) conductor.
    It makes no differences if the conductor is rotating.

    Does the << resonant structure >> of Thim make any difference in this respect?
     
  12. Feb 25, 2009 #11

    Ich

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    I don't think so. These are two coupled resonators, where should a redshift come from?
    But generally, try to calculate the mirror experiment in terms of wave vectors. You'll see that - from the mirror's viewpoint - the beam is redshifted, and so is the reflected beam. If you understand why there is no shift in the original frame, you see why there can be no shift in Thim's experiment.
     
  13. Feb 25, 2009 #12
    Ich,

    Is this, below, the kind of simplified setup you are thinking of?
    http://www.geocities.com/l.albatros/pictures/simpleThim.jpg
    This would be a kind of rotating-surface waveguide.
    For this situation, I don't expect any Doppler shift.
    Obviously, the rotation doesn't matter.
    Only matters the fact that the waveguide is a conductor.
     
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