Gamma-Ray Bursts; July 1997; Scientific American Magazine; by Fishman, Hartmann; 6 Page(s)

About three times a day our sky flashes with a powerful pulse of gamma rays, invisible to human eyes but not to astronomers¿ instruments. The sources of this intense radiation are likely to be emitting, within the span of seconds or minutes, more energy than the sun will in its entire 10 billion years of life. Where these bursts originate, and how they come to have such incredible energies, is a mystery that scientists have been attacking for three decades. The phenomenon has resisted study--the flashes come from random directions in space and vanish without trace--until very recently.

On February 28 of this year, we were lucky. One such burst hit the Italian- Dutch Beppo-SAX satellite for about 80 seconds. Its gamma-ray monitor established the position of the burst--prosaically labeled GRB 970228--to within a few arc minutes in the Orion constellation, about halfway between the stars Alpha Tauri and Gamma Orionis. Within eight hours, operators in Rome had turned the spacecraft around to look in the same region with an x-ray telescope. They found a source of x-rays (radiation of somewhat lower frequency than gamma rays) that was fading fast, and they fixed its location to within an arc minute.