IceCube collaboration confirms first sighting of neutrinos from space

New Scientist : Scientists have determined that two high-energy neutrinos detected by the South Pole IceCube Neutrino Observatory originated in outer space. Since the discovery of “Bert and Ernie” last year, the IceCube collaboration has been reexamining the data gathered from May 2010 to May 2012. So far they have found 26 more neutrinos of about 50 TeV each. Because that’s twice the expected number of atmospheric neutrinos, which are produced by cosmic rays hitting Earth’s atmosphere, about half must be coming from outside the solar system, according to IceCube team member Thomas Gaisser of the University of Delaware in Newark. Another indication that the neutrinos traveled a great distance is their distribution: Neutrinos are created with a well-defined flavorâmdash;either electron, muon, or tauâmdash;but can oscillate among the three flavors as they travel through space. The fact that the three types were equally represented indicates that they came a long way. As neutrinos only weakly interact with other matter, they may be able to be used to observe phenomena that optical telescopes cannot, such as the sources of cosmic rays, dark matter and dark holes, and stellar explosions.