23 September 2009
Late light licked?
From Ian Guy
In "The light that came late" (15 August, p 26) Anil Ananthaswamy cites esoteric theories based on string theory and quantum gravity to explain why high-energy photons from extremely distant gamma-ray bursts appear to arrive later than lower-energy photons produced in the same event. I would suggest a simpler explanation for this phenomenon: optical dispersion. …
