New Delhi, Oct. 7 -- Somewhere deep in space, a star explodes as a supernova, or a supermassive black hole devours matter at the centre of a galaxy. The event scatters radiation of various forms into space. Some of it reaches Earth as particles with energies too high to have originated on the planet. Scientists cannot trace these particles to their source, because interactions with magnetic fields have deflected them along a path nobody can retrace. Neutrinos could tell scientists more, but they are hard to detect. They rarely interact with light or matter, so they travel huge distances through space in a straight line. A high-energy neutrino detected on Earth could lead scientists to its source and to the event that produced it. The same p...