Physicists finally know where at least some of these high-energy particles come from, which helps make the neutrinos useful for exploring fundamental physics.
The cosmic neutrinos originating in the Milky Way muddle things further. There are no obvious sources of such high-energy particles in our galaxy—in particular, no active galactic nucleus. Our galaxy’s core hasn’t been bustling for millions of years.
What stands out in the new image of the sky is the intense brightness of sources like NGC 1068 and TXS. The Milky Way, filled with nearby stars and hot gas, outshines all other galaxies when astronomers look with photons. But when it’s viewed in neutrinos, “the amazing thing is we can barely see our galaxy,” said Halzen. “The sky is dominated by extragalactic sources.”
IceCube has detected dozens of neutrinos coming from NGC 1068, also known as Messier 77 — an active galaxy located 47 million light-years away. The well-studied galaxy, imaged here by the Hubble Space Telescope, is visible with large binoculars.Neutrinos offer rare clues that a more complete theory of particles must supersede the 50-year-old set of equations known as the standard model.