EVEN by the elevated standards of particle physics neutrinos are weird beasts. They travel within a whisker of the speed of light, have no electric charge, practically no mass and precious little will to interact with anything else. Billions penetrate every square centimetre of the Earth’s surface every second without so much as a quiver. This makes them rather hard to detect. So hard that Wolfgang Pauli, the Austrian physicist who postulated their existence in 1930, wagered a case of champagne that no one would ever do so. He lost the bet in 1956. Since then, neutrinos (of which there are now known to be three fundamentally different sorts) have allowed researchers to glimpse inside the sun, study exploding stars and examine the universe’s distant past.