The definite detection of nonterrestrial neutrinos, whether from the sun or from beyond the solar system, will yield a far deeper understanding of stellar interiors and, therefore, of how today’s universe came to be. — Science News, July 20, 1968.
In May 1968, researchers reported that a particle detector in South Dakota spotted ghostly subatomic particles called neutrinos from the sun, but only about a third as many as theories predicted. The shortage vexed physicists for decades, until the 2001 discovery that many of the sun’s electron neutrinos — the only kind the South Dakota detector was designed to find — switch flavors on their way to Earth, becoming muon and tau neutrinos (SN: 6/23/01, p. 388). That switch accounted for the sun’s missing neutrinos. Detectors have also glimpsed neutrinos spawned by supernova 1987A (SN: 3/7/87, p. 148) and even a supermassive black hole (SN Online: 7/12/18).
Editor’s Note: This story was updated July 13, 2018, to clarify that black holes are a source of neutrinos.