By John Gribbin Dinosaurs and other victims of mass extinctions could have been wiped out by epidemics of cancer triggered by massive bursts of neutrinos released by dying stars in our Galaxy, according to an American astrophysicist. Other scientists have speculated that cosmic rays from supernova explosions could cause mass extinctions. But nearby supernovae happen too infrequently to explain the majority. So Juan Collar of the University of South Carolina in Columbia started looking at less violent stellar collapses, which generate large numbers of neutrinos.
Neutrinos are reluctant to interact with everyday matter.
But if enough passed through the Earth in one go, then some would collide with the nuclei of atoms in living tissue. When this happens, the nuclei will recoil from the collision. Such recoils could damage DNA, producing cancer-causing mutations. Collar has calculated that a 'silent' star collapse will occur within 20 light years of the Earth roughly once every 100 million years. Collar compared the destructive potential of these recoils with conventional radiation damage.