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• About MM experiment

  In a moving passenger car, MM experiment is being done. On the ground, an observer stands. To this observer, are constancy of light speed and Lorentz contraction compatible ? And also, constancy of light speed and time dilation compatible ?

  • Thanks, Hiroji Kurihara for your time, if I understand your points correctly you are thinking about the speed of light and relation between two coordinates system in terms of length contraction and time dilation.
    1. The speed of light remains constant for all observers irrespective to their frame of references. (postulates of the special theory of relativity)
    2. The length contraction and time dilation are the results for the stationary observer in his frame of reference (it means this observer measure the event coordinates in his frame of reference, whatever he observe in terms of position and time coordinates, any physical quantity).
    3. How to transform this observation with the actual coordinates (coordinates of the actual event, where it happens in the frame of reference)? For this, we use Lorentz transformation equations in terms of space and time coordinates.
    4. Now your first question about the compatibility of the constancy of light and Length Contraction. Yes if you are looking dependency of the light in the explanation of length contraction, you can say. From my point, this is an assumption to understand the length contraction and similarly for time dilation in your second question.
    I don't think compatibility is the right word here, probably it creates confusion among the physical concepts. I have already tried to explain the importance of the speed of light for both the observers and how they see any event in their frame of references and further mathematically how we can interpret the observation of each observer using the Lorentz transformation.
    I hope I have cleared the doubt if you have any question or not satisfy with my answer please let me know that point. Your most welcome always Hiroji Kurihara.

• MM experiment (done in air)

  I found a word "extinction" in a book Special Relativity by French, A.P. 1968. It's written as follows (original text ; quoted from "Google book" ; in 5-2). "Thus, for example, with visible light, a thickness of about 10-5cm of glass or 0.1mm of air at atmospheric pressure is almost enough to erase any possible memory, as it were, of the motion of the original source" (10-5cm is 0.0001mm). What ?? If it is so (from frequency or from wavelength, "memory" is not erased), the result of MM experiment is only natural.

  Also, I found a book Theory of Relativity by Pauli, W 1958. In it, it is written as follows (quoted from the English version; in 1-6). "Rather should one say that ifor an observer moving with medium, light is propagated as usual with velocity c/n in all directions". Extinction will ensure it. Also it seems to be the "very and true explanation" for MM experiment !!

  Then, how about the experiment done in vacuum ? The emission theory seems to be promising.

  Sorry, I cannot receive E-mail. I do not have PC.