In the deep dark ocean, scientists made an exciting discovery! On February 13, 2023, a special telescope underwater saw a super strong particle called a neutrino. This was no ordinary neutrino; it had a huge amount of energy—220 petaelectronvolts! That’s a number way bigger than the previous record of 10 petaelectronvolts. Neutrinos are tiny particles that zoom through the universe. They are so small that they hardly ever bump into anything. In fact, many of them pass right through us all the time without us noticing. To catch these shy particles, scientists use big detectors filled with water or ice. They look for little flashes of light when neutrinos pass through. The telescope that spotted this record-breaking neutrino is called KM3NeT. It is super deep, about 3,450 meters underwater, near Sicily. It has many special light detectors called modules. When the neutrino came by, it created a splash of light, seen by over 28,000 sensors! Scientists think this powerful neutrino came from something amazing in space, like a supernova or a blazar. A blazar is a giant black hole that shoots out energy straight into our direction. The light from the neutrino made a smaller particle called a muon, which had a lot of energy, too—around 120 petaelectronvolts! But it’s still a mystery where the neutrino came from. Scientists looked at different possibilities and discovered that most clues point to a source far away in space. They think it could be from a very active black hole. This discovery is super important! If it turns out that this neutrino was made from cosmic rays and light left over from the Big Bang, it would be the very first of its kind ever seen. Scientists need to study more to unravel this exciting mystery about our universe!