SN 1987A

Supernova 1987a was a supernova in the Large Magellanic Cloud, a nearby dwarf galaxy. It occurred approximately 50 kiloparsecs from Earth, the closest supernova since Supernova 1604, which occurred in the Milky Way itself. The light from the supernova reached Earth on February 23, 1987. It was modern astronomers' first opportunity to see a supernova up close.

Approximately three hours before the visible light from SN 1987a reached the Earth, a burst of neutrinos was observed at two separate neutrino observatories, which had originally been built to study the solar neutrino problem. Although the actual neutrino count was small - less than twenty in all - it was a significant rise from the previously-observed background level. This was the first time neutrinos emitted from a supernova had been directly observed, and the results agreed with the predictions of theoretical supernova models.

The supernova remnant formed by debris from SN 1987a is one of the most-studied astronomical objects today.