# Neutrinos are slower than gravitational waves according to their mass?

Neutrino bursts are observed before the visible light of supernovas, most famously SN 1987A. Astronomers likewise expect gravitational waves.

Gravitational waves are supposed to travel at exactly the speed of light (right?), but neutrinos are merely relativistic. Would looking at the delay between the GW and neutrino waveforms help estimate neutrino mass?

• In the usual language of particle physics the neutrinos would be described as "ultra-relativistic". We're talking Lorentz factors of $10^6$ and up, so it will take quite a distant source and good consistent model of the supernova dynamics to sort out the travel time issues. – dmckee --- ex-moderator kitten Feb 21 '16 at 16:09
• @dmckee What part of our current understanding of SN dynamics would need further refinement in order to calculate this? – Jimmy G. Mar 14 '16 at 15:40