A mysterious, 16-minute-long explosion of energy detected from the beginning of the universe could be the result of a gravitational mirage — or something that astronomers can't explain.
But now, astronomers have discovered one named GRB 220627A that lasted for more than a thousand seconds — or just shy of 17 minutes. It arrived in two powerful bursts from an unknown event 2 billion years into the universe's existence. While astronomers haven't found any indication that the source of the burst was out of the ordinary, its length and double-burst nature has left them puzzled.
To investigate the strange signal, astronomers studied its afterglow — the fainter and less energy-intense light created by GRBs when shock waves from the initial explosion slam into gas and dust surrounding the burst star. The likeliest explanation is that the GRB is the product of gravitational lensing. First predicted by Einstein’s theory of general relativity in 1915, gravitational lensing is the warping of distant light sources by extremely massive objects such as galaxies and black holes — which would stretch, distort and create echoes of the GRB's signal before it arrived at Earth.