How Neutrino Beams Could Reveal Cavities Inside Earth

Geophysicists want to use neutrinos to 'x-ray' the Earth, a technique that could reveal undiscovered oil fields. But how practical is such a scheme?

Neutrinos are peculiar particles. They have little mass, no charge and come in three flavours. These flavours are not fixed. The strange thing about neutrinos is that once created, they change from one flavour to another as they travel.