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Speed of light=c=c(f)

  1. Oct 24, 2007 #1
    I read recently that the MAGIC telescope in Las Palmas detected a 4min divergence between photons of high and lower energy, which were traveling from galaxy Markarian 501. They say that the measurement is pretty accurate and it only remains to be re-confirmed.

    An old paper from J.Ellis, D. Nanopoulos & N.Mavromatos arises on the surface now, were it is suggested that the speed of light is not constant, but depends on the photon's frequency.

    Could someone pinpoint me a paper or something for more details? What does the rest of the community say about these claims?
  2. jcsd
  3. Oct 24, 2007 #2
    There was an earlier thread here on the subject that you may find interesting...

    p.s. This is probably more of a 'Beyond the Standard Model' subject
  4. Oct 24, 2007 #3


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  5. Oct 24, 2007 #4


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    According to all the signs I have seen, indicating physicists' response, the rest of the community has been skeptical.

    Discussion on several blogs where professionals were among those posting went in the direction of being displeased that MAGIC reported based on only one observation of the proposed effect.

    At least with two observations from sources at different distance one could say something about whether the delay occurred at the source, or accumulated during travel. In any case one observation is a pretty small sample.

    People in the professional community were also displeased that the authors used the phrase "probe quantum gravity" in the title. Since they had no convincing evidence that the delay accumulated during travel---and was not due to some unknown process at the source---it was necessarily a very preliminary finding and there was said to be an element of overstatement in the title.

    I didn't hear anybody cheering. And quite a lot of people booed, as I recall.

    The SPIRES library entry does not indicate acceptance for publication so far--I don't know how reliable that is.
    http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=FIND+EPRINT+0708.2889 [Broken]

    There have been four citations including the one in this paper, published in a Chinese journal.

    For me personally, what I think about it depends on what they follow it up with. The paper was based on observation of one flare in 2005. One would think that since they have been operating several years they might have observed several similar flares (from other active galactic nuclei besides Markarian 501). I havent seen any followup reports. The absence of followup is worrisome. But before dismissing their finding as a fluke, I personally will wait a while longer to see if it is eventually confirmed by other observations.

    Maybe there is some good news hidden here. At least the MAGIC team astrophysicists think they have an instrument that can see incoming TeV gamma photons from a flare and classify them according to energy. They think their instrument is sensitive enough to plot arrival time against energy and detect a delay of a few minutes. That looks like progress to me---if only in the department of telescope technology.
    Last edited by a moderator: May 3, 2017
  6. Oct 24, 2007 #5
    Thank you for your answer Marcus (and RetardedBastard for pointing the old thread)! I've also heard that Polchinski stated that if the results are true, then string theory confronts great problems. Why does this happens? Does it have to do something with Lorenz invariance?
  7. Oct 24, 2007 #6
    Concerning the Lorenz transformations:
    since an essential element to construct these transformations is the invariance of the speed of light when measured in two different inertial frames,
    if the speed of light is depending on the frequency and the latter on the place where the light is,
    we can guess that Lorenz transformations will become true only very locally ...!!!
    As longas the speed of light does not change too much in a given part of space-time.

    I hope it could give you a part of the reasons why this hypothetic result (if true) would change the face of physics.

    Concerning the string theory, I cannot help you. I am just reading the book of Brian Greene to learn the basics.
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