The NASA-led Swift mission opened its doors to a flurry of gamma ray burst action.
Scientists were still calibrating the main instrument, the Burst Alert Telescope (BAT), when the first burst appeared on December 17. Three bursts on December 19, and one on December 20, followed.
Swift's primary goal is to unravel the mystery of gamma ray bursts. The bursts are random and fleeting explosions, second only to the Big Bang in total energy output. Gamma rays are a type of light millions of times more energetic than light human eyes can detect. Gamma ray bursts last only from a few milliseconds to about one minute. Each burst likely signals the birth of a black hole.