The recent confirmation that at least some gamma-ray bursters (GRBs) areindeed at cosmological distances raises the possibility that observations ofthese could provide interesting constraints on the fundamental laws of physics.
Here we demonstrate that the fine-scale time structure and hard spectra of GRB emissions are very sensitive to the possible dispersion of electromagnetic waves in vacuo with velocity differences $\delta v \sim E/E_{\QG}$, as suggested in some approaches to quantum gravity.
A simple estimate shows that GRB measurements might be sensitive to a dispersion scaleEQG comparable to the Planck energy scaleEP∼1019 GeV, sufficient to test some of these theories, and we outline aspects of an observational programme that could address this goal.
