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The Speed of Light

  1. Mar 28, 2012 #1
    I don't want to beat a dead horse with anyone fixed on dogma, but I do understand the theory of relativity and the part on time dilation, I don't yet believe. Who knows of evidence that time dilation really does occur and that traveling faster than the speed of light really is and always will be impossible?


  2. jcsd
  3. Mar 28, 2012 #2


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    There is incontrovertible evidence of time dilation. It's based on the decay rate of some cosmic ray particle (I forget what) as it travels from the upper atmosphere to detectors on the ground. I'm sure someone here will provide details, or you can find it on the internet. Sorry about the lack of specifics.

    If you believe in FTL travel, well good luck with that.
  4. Mar 28, 2012 #3


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  5. Mar 28, 2012 #4


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    Muons are produced in the upper atmosphere in large numbers by cosmic rays. If they decayed as they do at rest, they would be essentially all decayed within 1 km of travel. Thus we would see only those produced in the bottom 1km of the atmosphere. This would be a very small number. Instead, essentially all the muons make it to the ground, and are a major reason many experiments have to done in mine shafts - to filter out this ever present barrage of cosmic ray produced muons.
  6. Mar 28, 2012 #5
    There is a huge amount of experimental evidence. For an overview, have a look at the Wikipedia article on tests of special relativity.
  7. Mar 28, 2012 #6


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    Or follow the link in the FAQ "Experimental Basis of Special Relativity" at the top of this forum.
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