GRB

Gamma-ray bursts are flashes of gamma rays from collapsing massive stars and merging neutron stars. Learn how they work, how astronomers catch them, and why the brightest one on record, GRB 221009A, still puzzles researchers.

A gamma-ray burst aimed at Earth from within a few thousand light-years would deplete the ozone layer in seconds, expose the surface to lethal UV, and possibly trigger a mass extinction. The good news: no such cosmic gun is currently aimed at us.