Gamma-ray bursts are short-lived events, lasting between a few milliseconds to a few minutes. The brightest of them emit more energy in a few seconds than our Sun will emit in its whole 10 billion-year lifetime. Gamma ray bursts occur several times daily somewhere in the universe. These fleeting explosions are precursors to the births of black holes.

Gamma-ray bursts are detected by orbiting satellites about two to three times per week. Since its launch in 2004, the Swift satellite has discovered over 292 gamma-ray bursts, and pin-pointed a further 320 bursts detected by other satellites. Swift's rapid response - it was named after the bird, which catches its prey "on the fly" - has been critical to understanding these titanic events.