Deep-sea neutrino telescope detects ghost particle of 'enormous energy'

LOS ANGELES - A neutrino detector deep in the Mediterranean Sea has detected the most energetic neutrino ever observed, according to findings published this week in Nature by the KM3NeT Collaboration.

Neutrinos—often called "ghost particles"—are nearly massless and pass through matter undetected. This newly observed neutrino, first detected in 2023, carried about 30 times more energy than the previous record-holder.

Researchers believe this high-energy neutrino could have come from an unknown cosmic accelerator or could be the first detection of a cosmogenic neutrino, a particle resulting from cosmic rays colliding with background radiation in space.

What is a neutrino and why is this discovery important?

Neutrinos are produced by stars like the sun, and trillions of them pass through our bodies every second. However, because they rarely interact with other particles, detecting them is incredibly difficult. Scientists rely on indirect methods, measuring the flashes of light that occur when neutrinos collide with matter.

"This is part of trying to understand the highest-energy processes in the universe," said study co-author Aart Heijboer of the National Institute for Subatomic Physics in the Netherlands.

How scientists detected the record-breaking ghost particle

The backstory:

The discovery was made using a deep-sea neutrino observatory still under construction. The telescope, submerged in the Mediterranean, is designed to detect neutrinos as they pass through the Earth.

In 2023, a high-energy neutrino struck matter inside the underwater detector, creating a tiny particle called a muon. As the muon moved through the observatory, it produced flashes of blue light, allowing researchers to measure its energy and determine the neutrino’s power.

Physicist Denver Whittington from Syracuse University, who was not involved in the study, said the discovery suggests there may be more high-energy neutrinos than previously expected.

The neutrino detected back in 2023 was around 30 times more active than the previous strongest example.

"It’s a sign that we’re on the right track, and it’s also a hint that maybe there might be a surprise," Whittington said.

Could more ultra-high-energy neutrinos be out there?

The exact origin of the neutrino remains unknown. Scientists will need further data from other observatories before they can pinpoint its source.

"It’s one event," said physicist Mary Bishai of Brookhaven National Laboratory. "We have to see what the other telescopes are also observing."

The discovery could pave the way for a better understanding of cosmic accelerators, the forces responsible for generating ultra-high-energy particles in the universe.