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Math vs Meaning

  1. Dec 29, 2005 #1
    I am quite aware of the overwellming evidence for the math of relativity, but are we sure that the meaning (time dilation, lenght contraction, ect.) are true? I guess what I am saying is are there any expiroments that have proven length contraction as in the barn and pole thought expiroment?
  2. jcsd
  3. Dec 29, 2005 #2


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    I'm not sure what you mean by "evidence" for mathematics. Mathematics is "valid" or "invalid" irrespective of relativity. Relativity is a physics theory and, as is true of all such theories, lives and dies by experimental evidence. The experimental evidence (light bending by the sun, the orbit of mercury, changing lifespan of high speed particles, time variations of fast space craft, etc.) is pretty much on the side of relativity.
  4. Dec 29, 2005 #3

    Tom Mattson

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    No, there isn't. The problem is that we don't have the technology to get macroscopic objects to move that fast. But we do have experimental evidence of time dilation and of the invariance of the speed of light. If one day we did the barn and pole experiment and found that length contraction does not occur, then that wouldn't make sense!
  5. Dec 29, 2005 #4
    Various explanations of electrostatic and magnetic forces on moving charges are based on the contraction of charge density when charges are in relative motion. see e.g http://galileo.phys.virginia.edu/classes/252/rel_el_mag.html
    I guess this is the most clear indication that length contraction actually exists, even at very low speeds.
  6. Dec 29, 2005 #5
    Thanks very interesting stuff.
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