Super-high-energy neutrinos from outside the Milky Way pepper Earth from all directions.
Neutrinos are created in the Universe's most violent environments and travel through it almost unimpeded, providing a way to study distant astronomical objects. A team at the IceCube Neutrino Observatory at the South Pole reported the first evidence for neutrinos from outside the Galaxy in 2013, using observations of the Southern Hemisphere sky. Now the team has used a different method to detect more than ten super-high-energy neutrinos from the Northern Hemisphere. IceCube detects tracks of light (pictured) when neutrinos interact with particles in the ice that forms part of the detector.
As with the previous result, the neutrinos come from all over the sky rather than being concentrated in the Galactic plane, bolstering the claim that they come from farther afield, say the authors.