It all started when Swift’s Burst Alert Telescope picked up a powerful gamma-ray burst on March 28, at which point it notified scientists the world over. Astronomers sometimes see gamma-ray bursts like this when a star dies, but these bursts generally last a few hours or less.

The plot thickened when the burst didn’t fade away. Dozens of telescopes turned toward the enigma, and it was concluded that the source of the gamma-ray burst is at the center of a galaxy some 3.8 billion light-years away. The burst was still repeating itself, brightening and fading over and over. There are objects in our own galaxy known to produce such repetitive bursts, but at a fraction of the intensity.