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Light Exceeds Its Own Speed Limit?

  1. Jan 9, 2015 #1
    People have asked this question on this forum before. Yet no one has answered or done background check up.

    Reading this has confused my understanding of Special Relativity even more.




    (not sure of the validity of the last article)

    A google search doesn't reveal much else on this...
    Anyone care to elaborate on this? Where's the experimental data info, extra research etc?

    How could the speed of light exceed through other medium?

    Also: "A paper on the second new experiment, by Daniela Mugnai, Anedio Ranfagni and Rocco Ruggeri of the Italian National Research Council, described what appeared to be slightly faster-than-c-propagation of microwaves through ordinary air, and was published in the May 22 issue of Physical Review Letters."
    (First article)
  2. jcsd
  3. Jan 9, 2015 #2
  4. Jan 9, 2015 #3


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    It's usually ill advised to try to get too much physics from popular news sites. Especially for attention grabbing headlines like "breaking the speed of light limit". Do you have links to the actual published papers?

    What I suspect is happening is some modified version of the phase velocity being faster than the speed of light, which is not actually a problem.
  5. Jan 9, 2015 #4

    Vanadium 50

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    Did you reed the reedsmith story?
  6. Jan 9, 2015 #5


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    Hmm... well the only way I could see the speed of light "exceeding c" is through general relativity, where spacetime is warped due to a gravitational field. It would (at least as far as my miniscule amount of SR/GR knowledge goes), however, only appear more blue shifted, which could, since we're subject to the curvature of spacetime, appear as a faster than c propagation. I could also be speaking nonsense, though. Additional input from someone such as @WannabeNewton would be great in this case.
  7. Jan 9, 2015 #6


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    Matterwave said
    By all that is holy, I swear that I am going to lock this thread if the next post is not a reference to the actual paper.
  8. Jan 9, 2015 #7


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    Do you really expect us to get the paper out of a pop sci article? The closest i could get via google is this: L J Wang et al. 2000 Nature 406 277
    I don't have a nature subscription though, so I can't access it, and I don't want to pay they're per article fee (it's RIDICULOUS last I looked ~$100/article).
    This is why I love arxiv.
  9. Jan 9, 2015 #8


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    Some of these references are nearly fifteen years old, which is a fairly strong hint that there's nothing here.
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