Asked by: C Osborne, South Wales
Gamma-ray bursts (GRBs) are extremely energetic flashes of radiation caused by the collapse of massive stars to form neutron stars or black holes. They are the most energetic events in the Universe, but extremely rare.
The record for the most energetic is named GRB 130427A, which occurred on 27 April 2013. It was detected by many telescopes, on Earth and in space, and occurred in a galaxy in the constellation of Leo, about 3.8 billion light-years away. This is relatively nearby for a GRB, which explains why it was so bright. In fact, GRB 130427A was more than five times brighter than the previous record.
It’s the biggest explosion astronomers know about, after the Big Bang itself. If it had happened in our arm of the Milky Way, it would have destroyed all life on Earth.