The Kamiokande, an underground facility in Japan for detecting proton decay, registers a pulse of neutrinos just as a supernova explosion is detected in the Large Magellanic Cloud. Neutrinos have been traveling through space for 170,000 years before reaching it. This is a huge stroke of luck: the last supernova visible to the naked eye was seen in 1604. A supernova releases about 10^39 neutrinos (a terrifying amount). Eight neutrinos are detected deep within the Homestake gold mine, New Jersey, by the IMB experiment, and eleven are detected by the Kamiokande. This also allows the temperature of the star before it exploded to be predicted: 40 billion degrees.
