Astrophysical Probes of Lorentz Violation

Physical intuition suggests that the vacuum should fluctuate strongly at the Planck scale due to quantum effects, a phenomenon called space-time foam. This would be a dynamical medium that could affect the propagation of energetic particles, violating Lorentz invariance. Many of the most sensitive probes of this possibility are provided by energetic, time-varying astrophysical sources such as pulsars, gamma-ray bursters and active galactic nuclei. This talk will review available astrophysical constraints on Lorentz violation in the propagation of photons, neutrinos and gravitational waves.