Record-breaking neutrino is most energetic ever detected

Astrophysicists have observed the most energetic neutrino ever. The particle — which probably came from a distant galaxy — was spotted by the Cubic Kilometre Neutrino Telescope (KM3NeT) anchored to the floor of the Mediterranean Sea. KM3NeT picks up light emitted by high-energy, electrically charged particles such as muons — which can be produced when high-energy neutrinos smash into Earth’s atmosphere. In early 2023, it detected a muon that carried approximately 120 petaelectronvolts of energy. From the particle’s energy and its near-horizontal trajectory, researchers concluded that it was probably produced by a neutrino more than 20 times more energetic than any seen before.