For the fourth time, physicists have spotted a neutrino morphing from a type called a muon neutrino to a type called a tau neutrino. The observation comes from the team working with a massive particle detector called Oscillation Project with Emulsion-tRacking Apparatus (OPERA) in Italy's subterranean Gran Sasso National Laboratory. OPERA (above) took data from 2008 to 2012 and created quite a sensation in September 2011, when it announced (mistakenly) that neutrinos fired from the European particle physics lab, CERN, 730 kilometers away in Switzerland, appeared to travel faster than light. But OPERA's main goal was to spot muon-neutrino-to-tau-neutrino conversion, which was predicted by theory. We may not have heard the last of OPERA: Researchers still have data in the can—and they've issued a press release with each tau neutrino they've seen.