Unexpected lines in x-ray spectra hint that the universe's most energetic explosions are triggered by a delayed-action fuse. Scientists have fingered a new suspect in a case of unimaginable cosmic violence. The mystery, which has haunted astrophysicists for 3 decades, is what causes gamma ray bursts—short, intense flashes of high-energy photons that occur about once a day somewhere on the sky. In early 1997, observations by the Italian-Dutch BeppoSAX satellite and follow-up studies with ground-based telescopes traced the flashes to cataclysmic explosions in distant reaches of the observable universe. But what could cause the explosions, which produce more energy in 1 second than the sun will emit in its entire 10-billion-year lifetime?
展开▼
