The Antares detector is shielded from the background of cosmic rays by 2000 metres of water. Its abyssal depth provides total darkness, disturbed only by the faint light from a few bioluminescent animals. The telescope's basic principle is to make Earth itself the neutrino target. While the Earth stops other particles, neutrinos can pass all the way through. Along the way, some of them will collide with the nucleus of an atom. A very rare occurrence statistically, this collision produces a muon, a charged particle similar to an electron that moves in the same direction as the original neutrino.