Combining quantum physics with gravity is one of the ultimate challenges in physics, but the energies needed to test the various competing theories of quantum gravity are far beyond the scope of existing accelerator technology. A group of theoretical physicists from Oxford, Neuchâtel, Geneva and Athens has now suggested an alternative way to probe quantum gravity based on gamma-ray bursts. These short-lived flashes of gamma-radiation are among the most energetic phenomena in the Universe. They propose that an energy-dependent dispersion predicted by some theories of quantum gravity could manifest itself in the arrival time of photons from a gamma-ray burst (Nature 393 763). According to their calculations, existing gamma-ray satellites should be able to detect this effect.