By Ron Cowen
Gamma-ray bursts, the most powerful explosions in the universe, just got more mysterious. New observations challenge the theory that astronomers had constructed for the origin of many of these cosmic flashbulbs.
These flashes of high-energy radiation are a million trillion times as bright as the sun. According to the leading theory, any gamma-ray burst lasting more than 2 seconds is associated with a supernova, the explosive death of a massive star. A high-speed jet of material emerging from the collapsing star, which becomes either a neutron star or a black hole, generates the burst. At about the same time, a wind or shock wave carrying radioactive nickel-56 powers the visible supernova.