The 50 second burst, known as GRB971214, was detected by the two satellites. The Italian/Dutch BeppoSAX satellite gave the precise position of the blast, while NASA's Compton Gamma Ray Observatory measured its brightness. Further observations at different wavelengths by a collection of ground and space-based telescopes measured the distance to the optical counterpart of the burst to be 12 billion light years. The Hubble Space Telescope then provided a more detailed image of the 'host' galaxy. The vast distance to the galaxy, plus the brightness of the burst, implies an enormous energy release - several hundred times that of a supernova, until now the most energetic phenomenon known in the universe. Even more energy may have been released as neutrinos and gravity waves.

"Most of the theoretical models proposed to explain these bursts cannot explain this much energy, " said Shrinivas Kulkarni of Caltech, a co-author on two of the papers. "However, there are recent models, involving rotating black holes, which can work. On the other hand, this is such an extreme phenomenon that it is possible we are dealing with something completely unanticipated and even more exotic."