The Ancient Collision That Everyone Saw

The year is 1987, and on February 23rd, three separate neutrino observatories experienced a huge burst in detections. Although initially unsure of their origin, the next day a Supernova was discovered in the Large Magellanic Cloud, a small satellite galaxy of the Milky Way visible in the southern hemisphere.  Known as 1987A, it was the closest supernova observed in centuries, and was observed by astronomers around the world as it brightened and then slowly dimmed.  By combining the visible observations with the neutrino data, scientists learned about how supernovae occur, constrained the mass of the neutrino, and opened a new...