Cosmic explosion may be brightest ever seen, astronomers say

A cosmic explosion that blinded space instruments may be the brightest ever seen, astronomers have said.

The blast, which occurred two billion light years from Earth in October, produced a pulse of intense radiation that swept through the solar system, triggering detectors on multiple spacecraft.

Scientists said the event was a gamma-ray burst (GRB), known for being some of the strongest and brightest explosions in the universe.

Astronomers said it was the brightest of all time since the beginning of human civilisation, blinding most gamma-ray instruments in space.

It meant researchers could not measure the real intensity of the emission and had to reconstruct its energy expenditure from past and present data.

An analysis of 7,000 GRBs suggests the event, dubbed GRB 221009A, was 70 times brighter than any yet seen and only occurs once every 10,000 years.

Dr Dan Perley, of the Astrophysics Research Institute at Liverpool John Moores University - who followed the event with the University's Liverpool Telescope on the Spanish island of La Palma, said: "There is nothing in human experience that comes anywhere remotely close to such an outpouring of energy. Nothing."

Astronomers believe GRB 221009A was the result of a massive star collapsing in on itself to form a black hole.

Dr Perley said: "The star would have been many times more massive than the sun, probably 20 times as massive or more."

GRB 221009A was thought to be so bright because it was much closer to Earth compared to other known GRBs and the beam of electromagnetic radiation happened to be pointing in the direction of the planet.

GRBs also produce a supernova but astronomers are yet to ascertain whether that happened in this case.

They are typically followed by a shockwave that emits lower energy radiation, known as an afterglow, that gradually fades over time.

The findings are reported in two separate papers in the Astrophysical Journal and Astrophysical Journal Letters.

-sky news