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Fraser
2007-Oct-03, 09:36 PM
The speed of light is the speed of light, and that's that. Right? Well, maybe not. Try and figure this out. Astronomers studying radiation coming from a distant galaxy found that the high energy gamma rays arrived a few minutes after the lower-energy photons, even though they were emitted at the same time. ...

Read the full blog entry (http://www.universetoday.com/2007/10/03/high-energy-gamma-rays-go-slower-than-the-speed-of-light/)

zrice03
2007-Oct-04, 12:00 AM
Using my mad math skillz, I calculate these high-energy gamma rays would be traveling about 4.5 microns per second slower than the accepted speed of light to create the observed difference.

Of course, that only if there is no observational error. Perhaps some kind of intergalactic cloud absorbed then re-emitted the gamma rays on the way from Markarian 501 to Earth and the difference was about 4 minutes.

Fortunate
2007-Oct-04, 12:51 AM
We've already discussed this here (http://www.bautforum.com/questions-answers/63917-breakdown-relativity-also-magic-delayed-photon.html).

nephilin
2007-Oct-04, 02:00 PM
Is the process really well enough understood to be sure the Gamma rays of different energies are generated at the same time?

antoniseb
2007-Oct-04, 02:05 PM
Is the process really well enough understood to be sure the Gamma rays of different energies are generated at the same time?
The paper by the observers says we are not sure of the process, and it could be something strange that causes 10TeV gammas to be released four minutes after the 500GeV gammas. They think the fact that the delay matches some quantum gravity predictions is probably a good sign for their interpretation.

Fortunate
2007-Oct-04, 02:10 PM
Is the process really well enough understood to be sure the Gamma rays of different energies are generated at the same time?

I don't think so. From SciAm article (http://blog.sciam.com/index.php?title=hints_of_a_breakdown_of_relativity _theor&more=1&c=1&tb=1&pb=1
).


Either the high-energy gammas were released later (because of how they were generated) or they propagated more slowly.

John Mendenhall
2007-Oct-04, 04:48 PM
The delay time of 4 minutes over 500 million years seems rather small to me . . .

Essel
2007-Oct-05, 12:00 PM
Before we come to the conclusion of high energy Gamma rays going slower than the speed of light, we ought to be sure about:

a) The generation process at Markarian 501
b) Interpretation errors of indirect observation on earth.
c) possibility of multiple re-emmissions in the intergalactic space.

How about comparing the red-shift of the gamma rays with the visible part of the galaxy?

trinitree88
2007-Oct-05, 12:19 PM
The emission of hard gammas after soft ones has already been seen before. Duly noted.:shifty:pete see:http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v489n1/35715/35715.html?erFrom=8116967011413628771Guest

pghnative
2007-Oct-05, 12:36 PM
How common are these "blazars"? One could quickly resolve whether it is a generation effect (or an observational error) by demonstrating if the time lag is proportional to distance.

Fortunate
2007-Oct-05, 03:21 PM
Before we come to the conclusion of high energy Gamma rays going slower than the speed of light...

Read the posts and linked articles of the previous baut thread (linked in post #3 above). My understanding of some of the things I have read so far boils down to the following: the conjectured mechanism would not violate SR in that the medium would be a quantum foam rather than a "pure vacuum." The QF, I am told, might have a nontrivial index of refraction, causing light to move through it at speeds less than c. But in familiar refractive media, the speed varies with the wavelength, with more energetic photons traveling more slowly.

Jerry
2007-Oct-05, 08:14 PM
Call it foam, dark energy, or suck - it is at least one more free parameter.

Fortunate
2007-Oct-05, 08:45 PM
Jerry,
My use of the word "quantum foam" may be a misnomer, since the term may be more tied to a particular type of theory than my concept is. Again, all "my ideas" on this topic are second-hand and derive from hearsay, as I am not capable of performing any of the relevant calculations myself. I first came across the idea of different wavelengths traveling through space at different rates in an article about loop quantum gravity, a topic on which my ignorance is so intertwined with confusion as to be indistinguishable. The author had drawn a bunch of polygonal or polyhedral networky things and the explanation of why different wavelengths would travel at different speeds totally baffled me. But if the authors turn out to be right, they get feathers in their caps for a correct prediction.

peterr
2007-Oct-05, 08:46 PM
Space is not entirely empty. Why not a dispersive media in between? Like a prism that splits the optical spectrum with different wavelengths because of a difference in speed that varies with frequency. Since the viewpoint is normal to the direction this would manifest itself as arrival time differences rather then the angular dispersion we usually observe with a triangular prism.

edvijai
2007-Oct-06, 07:56 AM
May be it is time to re-visit the good old experiments using light of specific wave lengths seperately. Also, repeat the Gamma Ray exp in the visible light spectrum

antoniseb
2007-Oct-06, 08:25 AM
May be it is time to re-visit the good old experiments using light of specific wave lengths seperately. Also, repeat the Gamma Ray exp in the visible light spectrum
When we observe the short GRBs they last tens to hundreds of milliseconds, and all the gammas and xrays we observe (under 1MeV) come at essentially the same time, after traveling much further than the 450 million light years that these high energy gammas went. It would be hard to set up an experiment more precise than that.

tobyvoss
2007-Oct-07, 03:49 PM
high energy photons (energy eq. mass, right?) experiencing more of a delay than lower energy photons while barely escaping a super massive black hole's event horizon?
i somehow utterly fail to be astonished. compare to chromatic aberration in gravitational lensing.
-please note i'm a junior member.

Tensor
2007-Oct-07, 05:37 PM
Call it foam, dark energy, or suck - it is at least one more free parameter.

And just one more chance for you to insert a comment about the mainstream when you have no idea of what the idea presented really means. If you really have doubts about LQG. Please point out exactly where and what calculations of the theory you disagree with. Instead of tossing off meaningless comments.

Argos
2007-Oct-10, 01:36 PM
So what's happening? Nobody knows, and this could turn into an entirely new field of physics. The researchers are proposing that maybe the radiation is interacting with "quantum foam".

So, the energy of the empty space would induce a drag on the motion of photons.

Itīs interesting that I have entertained myself with the idea that the quantum foam is the ultimate explanation for why the speed of light is c.