Quantum gravity is quite elusive at the experimental level; thus a lot of
interest has been raised by recent searches for quantum gravity effects in the
propagation of light from distant sources, like gamma ray bursters and active
galactic nuclei, and also in earth-based interferometers, like those used for
gravitational wave detection. Here we describe a simple heuristic picture of
the quantum fluctuations of the gravitational field that we have proposed
recently, and show how to use it to estimate quantum gravity effects in
interferometers.Comment: LaTeX2e, 8 pages, 2 eps figures: Talk presented at QED2000, 2nd
Workshop on Frontier Tests of Quantum Electrodynamics and Physics of the
Vacuum; included in conference proceeding