A deep-sea neutrino telescope spots the most energetic ghost particle yet

NEW YORK (AP) — A neutrino detector submerged in the Mediterranean Sea has sniffed out the most energetic ghost particle yet, scientists reported Wednesday.

The newly detected neutrino is around 30 times more active than the previous recordholder. Scientists think it came from outside the Milky Way galaxy but its exact source remains a mystery.

Neutrinos spew from stars like the sun and trillions stream through our bodies every second. They're known as ghost particles because their mind-bogglingly small mass makes them difficult to spot.

Scientists aren’t able to detect neutrinos zipping around on their own. Instead, they measure what happens when the particles bump into other bits of matter.

Two years ago, a neutrino collided with matter and produced a tiny particle called a muon that pinged through the underwater detector, producing flashes of blue light. The researchers worked backward to estimate the energy of the neutrino and published their findings Wednesday in the journal Nature.

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

The detector that made the discovery is part of a deep-sea neutrino observatory that’s still under construction. Neutrino detectors are often located underwater, beneath ice or deep underground to protect against radiation at the Earth's surface.

Finding this energetic neutrino so early could mean there are more out there than scientists initially thought.

“It's a sign that we're on the right track, and it's also a hint that maybe there might be a surprise,” said physicist Denver Whittington from Syracuse University who was not involved with the new research.

It's too early to pin down the source of the neutrino, said physicist Mary Bishai with Brookhaven National Laboratory.

“It's one event,” said Bishai, who was not involved with the study. “We have to see what the other telescopes are also observing.”

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