A telescope at the bottom of the Sea

On the bottom of the Mediterranean, Dutch scientists are helping to build a completely new kind of telescope. This instrument does not look at light, but at neutrinos: ghostly elementary particles that reach us from spectacular objects in the universe, such as the active centres of galaxies, where large black holes drive particle acceleration up incredible energies. Studying neutrinos from such sources opens a completely new form of astronomy, but requires a detector that is nothing like a normal telescope. The first discoveries have been made with the IceCube detector on the South Pole. The next instrument is the KM3NeT telescope, built in the darkness of the deep sea, at a depth of 3 km. We will use this "neutrino telescope" to scan a cubic kilometer of seawater for the traces of cosmic neutrinos. In the talk, the science of cosmic neutrinos as well as the spectacular means of detecting them will be discussed.