KM3NETAnchored by cables, one of the detectors descends to the bottom of the MediterraneanKM3NET
On February 13, 2023, an underwater device detected a neutrino (an extremely light and abundant subatomic particle with no electrical charge) with the highest energy ever observed: at 220 petaelectronvolts (PeV, one of which equates to 1015 electronvolts), it had the same energy as a ping-pong ball dropped from a height of one meter. The most previously measured had been just 10 PeV. Based on its unprecedented energy level, it could be the first cosmogenic neutrino ever detected, originating from cosmic rays, another type of ultra-energetic particle, that interact with photons (light particles) in the background radiation left by the big bang, the explosion that gave rise to the Universe. The device that detected the ultra-energetic neutrino was one of two arrays belonging to the Cubic Kilometer Neutrino Telescope (KM3NeT), located 3,450 meters (m) below the surface of the Mediterranean Sea near southern Italy. The two 700-meter-tall detection units are anchored to the seabed and positioned about 100 m apart. Each is equipped with 18 digital optical modules containing 31 light-sensitive detectors. More than 28,000 photons were detected when particles produced by the passing neutrino crossed through the detector. The KM3NeT Collaboration involves 360 scientists from 68 institutions in 21 countries (Nature, February 12; ScienceAlert, February 13).
Republish