A neutrino detector in Antarctica has found heaps of high-energy neutrinos coming from distant galaxies, but none from within our own – until now
By Leah Crane
29 June 2023
Neutrinos from within the Milky Way have been detected in Antarctica
Shutterstock / Denis Belitsky
After more than a decade of searching, the IceCube neutrino detector in Antarctica has finally found high-energy particles from within the Milky Way. This discovery opens a window into how cosmic rays shape the universe.
The disc of the Milky Way is incredibly bright in every wavelength of light – particularly in gamma rays, which tend to be accompanied by neutrinos. But any neutrinos from within our galaxy have historically been overwhelmed by stronger signals from other galaxies, so we haven’t been able to observe them.
“It took us 10 years to find the galactic plane in neutrinos,” says IceCube head Francis Halzen at the University of Wisconsin-Madison. “It’s totally counterintuitive. It’s like if you went outside at night and saw a sky bright in active, distant galaxies but no Milky Way.”
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The researchers applied a new machine learning algorithm to the data IceCube gathered between 2011 and 2021. This allowed them to flag signals that had previously been discarded as noise, retaining more than 20 times as many as the methods previously used to select data for analysis.
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We are finally closing in on the cosmic origins of the “OMG particle”
They found a diffuse glow of high-energy neutrinos that seem to come from within our own galaxy, but the specific sources of these neutrinos remains elusive. Generally, neutrinos form when cosmic rays, which are high-energy particles travelling through space at nearly the speed of light, collide with other matter and create showers of fundamental particles and radiation.