Hunting neutrinos, of course. University of Wisconsin professor Francis Halzen developed the idea of the project now called IceCube. Halzen is a professor of physics and wanted to study neutrinos which are subatomic particles (meaning smaller than atoms). Neutrinos are emitted by cosmic events such as supernovas and black holes. These neutrinos are very difficult to find and Professor Halzen theorized that he could locate them more easily in ice.IceCube is an observatory that instead of looking at stars looks into ice. Engineers drilled through the ice with hot water up to one and a half miles deep. They dug a total of 86 holes. (See here for a great picture.) Along the way, they placed sensors to detect the neutrinos. When a neutrino collides with an atom of ice, the collision creates a particle called a muon. The muon emits blue light and the sensors can pick this up. Voila, Professor Halzen finds his neutrinos.