wolram said:
Will this muddy QG light time arrivals?
Wolram, your intuition seems correct to me. the large scale structure has these big voids in it and that should influence travel time, not necessarily in any way dependent on energy however
I should admit that after the MAGIC collaboration reported that ONE incident where they had observed a delay that depended on ENERGY there was a strong skeptical reaction on the part of a lot of people---on blogs and I imagine elsewhere too.
A lot of people are taking the position that they are going to have to see quite a number of gammaray flares analyzed, and the same energy-dependent delay found in each one, before they will believe it's real.
I can sympathise with this. So for now I will try carefully not to suggest that the delay is real---it could be just a random thing in the data or some effect at the source.
I would expect that the swiss cheese will not interfere too much because the whole flare or the whole burst would be affected by voids equally if at all---low and high energy alike.
but the whole thing will just have to be forgotten if it is not repeatedly observed.
GLAST should help. It has been delayed so often that I dread further delays---but barring such troubles it is scheduled to be launched February 2008.
http://www.nasa.gov/missions/highlights/schedule.html