Neutrinos, created by violent phenomena such as black holes and exploding stars, could hold the key to the universe’s most distant and mysterious events.
Antarctic scientists have confirmed the existence of cosmic neutrinos – ghostly particles that have traveled from the Milky Way and beyond. These particles carry messages from distant galaxies, and could potentially help solve several cosmic puzzles.
Neutrinos are subatomic particles created by some of nature’s most energetic and violent phenomena, such as black holes and massive exploding stars. Spotting them is difficult, however, because they have very high energy and nearly no mass. If you can catch a glimpse of them they make the ideal long-distance messenger because the information they hold is pristine, unchanged as the particles travel millions of light years through space.
Now, Albrecht Karle at the University of Wisconsin-Madison and his colleagues working at the IceCube Neutrino Observatory in Antarctica have sorted through billions of particles that bombarded their detectors between 2010 and 2012 and identified 21 ultra high-energy muons – secondary particles created on the rare occasions that neutrinos interact with other particles.
They say that these muons are indicative of neutrinos that could have traveled from our solar system and beyond.
The observations, which were reported today in Physical Review Letters, were made by sifting through data collected from thousands of optical sensors arranged like strings of pearls sunk beneath the ice at the South Pole.
In 2013, scientists used these sensors to glimpse two candidate neutrinos which they subsequently nicknamed “Bert and Ernie” . Two events was too few to pinpoint where they came from, but these extra sightings will help researchers locate their source – potentially outside the Milky Way.
When a neutrino smashes into another particle, the subsequent muon leaves a trail of light that mirrors the trajectory of the neutrino – allowing scientists to work out where the neutrino came from. That in turn provides vital information as to the position and activity of many of the universe’s most distant and mysterious cosmic events.
“This is an excellent confirmation of IceCube’s recent discoveries, opening the doors to a new era in particle physics,” said Vladimir Papitashvili , astrophysics and geospace sciences program director of the National Science Foundation’s Division of Polar Programs.
“These neutrinos may give us an understanding about the origin of the most energetic processes in the universe,” said Karle. “They may tell us about fundamental properties of particle physics and the origins of dark matter.”