Cosmic neutrino. The computer reconstruction shows the path of a muon (blue line), created by a cosmic neutrino, in the AMANDA detector at the South Pole. AMANDA consists of strings of phototubes (white lines) buried up to 2400 m deep in the Antarctic ice. The phototubes detect faint Cerenkov radiation emitted when high-speed muons travel through the ice. By recording the time (figures showing nanoseconds) after the first light is recorded, the muon's direction can be calculated. Its upward track indicates it was created when a neutrino that had travelled all the way through the earth from the northern hemisphere interacted in the ice or rock beneath AMANDA.