When neutrinos penetrate matter, the collision causes a brief flash of bluish light called Cherenkov radiation. If such a flash occurs in a block of ice that is free of air bubbles or other impurities, the Cherenkov light can be detected by sensitive photosensors. Astrophysicists have taken advantage of this unusual property of ice to build the world’s largest neutrino telescope. The Antarctic Muon and Neutrino Detector Array (AMANDA) project consisted of nineteen long chains of photodetectors embedded more than a mile deep in the Antarctic ice at the South Pole. AMANDA was then incorporated into an even larger project called IceCube, an international scientific project that incorporates thousands of photodetectors suspended throughout a cubic kilometer of Antarctic ice.