In February 2023, a cosmic particle detector housed deep in the Mediterranean Sea recorded the arrival of a neutrino with approximately 20 to 30 times more energy than any other neutrino documented previously. Labelled KM3-230213A, the particle had a calculated energy of 220 petaelectronvolts (PeV), far greater than the 10 PeV of the previously most energetic neutrino. The finding generated a lot of excitement among physicists, but raised also many questions.
Neutrinos are the most abundant particles in the universe with mass. They are a type of fundamental particle, which means they don’t break down into smaller constituents, and are therefore very small and