A 4 Billion Light-Year Journey Ends At The South Pole

"Scientists for the first time have been able to pinpoint the source of an extremely powerful version of a neutrino, a ghostly particle that can travel virtually unimpeded through space."

"It's an achievement that opens a whole new way of looking at the universe."

"The neutrino was detected by a South Pole observatory called IceCube that was specifically designed to catch the particles. It consists of a cubic kilometer of ice festooned with more than 5,000 detectors."

"Neutrinos don't interact with much, but occasionally one will strike another particle, giving off a kind of light known as Cherenkov radiation that IceCube's detectors can pick up."

"When a particularly high-energy neutrino is captured, IceCube sends out an alert."

"'We had this neutrino alert in September 2017,' says Olga Botner, a particle physicist at Uppsala University in Sweden and a member of the National Science Foundation-funded IceCube scientific team. On Sept. 22, to be precise."