Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Gamma ray burst, LQG and String Theory

  1. Oct 22, 2008 #1
    I was reading this:

    I was wondering if there is any up to day info about the speed of gamma ray burst that could confirm or debunk these claims. Or are LQG and String Theory in troubles?
  2. jcsd
  3. Oct 22, 2008 #2


    User Avatar
    Gold Member

    Hi, Jimmy. Quite a few years ago an associate (and former protege, IIR) of Smolin's predicted this frequency-dependent delay in arrival times. Her name is Fotini Markopoulou and she thought that if light interacts with the space through which it propagates, AND if space has a fine structure, then high frequency, high energy EM ought to interact more frequently, and thus be delayed WRT low frequency, low energy EM. She pinned her hopes on data from GLAST, though MAGIC might have scooped GLAST, if the observations and interpretations from last year are reliable. There are a couple of levels of interpretation at interest, here. If Glast observations indicate that there is a frequency-dependent delay in EM arrival times, that would be VERY important, if it could be determined that the delays were (likely) not due to some local mechanism at the GRB. If follow-up observations with similar GRBs show that the magnitude of the delay is proportional to the redshift of the host, we would have to rethink all of cosmology.

    The former is posited. The latter is extrapolate from the former, and IMO should be observed. If not, the former observation cannot be said to result from interaction of EM with space along its path of propagation, and is falsified.
  4. Oct 23, 2008 #3
    If photons interact with space itself, then don't interactions by definition exchange energy and momentum and so the photon would gradually lose energy as it travelled through space?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Gamma ray burst, LQG and String Theory