On Feb. 24, 1987, light from a supernova that exploded 168,000 years ago in the Large Magellanic Cloud, a neighbor of the Milky Way, reached Earth. Astronomers Ian Shelton and Oscar Duhalde at the Las Campanas Observatory in Chile first reported the supernova, called SN 1987A (or simply 87A), which was one of the brightest in nearly four centuries.