An observatory still under construction at the bottom of the Mediterranean Sea has spotted what could be the most energetic neutrino ever detected. Such ultra-high-energy neutrinos — tiny subatomic particles that travel at nearly the speed of light — have been known to exist for only a decade or so, and are thought to be messengers from some of the Universe’s most cataclysmic events, such as growth spurts of supermassive black holes in distant galaxies. “It would be really interesting to see where in the sky the neutrino originated,” says Nepomuk Otte, an associate professor in the School of Physics. Otte is leading a proposed project — with a prototype now being tested in Utah — that would search for Earth-skimming neutrinos by monitoring the atmosphere just above the horizon for flashes of light.