Tests of relativity from SN1987A

The observation of neutrinos and light from the recent supernova in the Large Magellanic Cloud has provided us with a wealth of new information, both about stellar collapse and about neutrinos. I point out that, in addition, the nearly simultaneous arrival of the photons and neutrinos after a journey of some 160 000 yr shows that the limiting velocity of electron antineutrinos is equal to that of light to an accuracy ∼2×${10}^{\mathrm{-}9}$, which is a more stringent test of special relativity than previous Earth-based measurements. It also provides an important new test of relativity and probes the structure of spacetime on intergalactic scales.