Seven billion years ago, 7 billion light-years away, a gamma-ray burst sent a blitz of photons tearing into space. Some of them headed for Earth.
"The analysis Nemiroff et al. are reporting is very nice and a striking confirmation that these studies of Planck-scale structure of space-time can be done, as some of us suggested long ago," said Amelino-Camelia, an originator of the idea that gamma rays could reveal the building blocks of space-time. "But the claim that their analysis is proving that space-time is 'smooth with Planck-scale accuracy' is rather naive."