Most powerful explosion ever recorded ‘was birth cry of black hole’

This NASA illustration shows a burst of gamma rays from deep in space that scientists believe may have been the biggest explosion since the Big Bang, astronomers announced May 6. The burst was first seen Dec. 14, 1997, by the Italian/Dutch BeppoSAX satellite and NASA's Compton Gamma Ray Observatory satellite and was measured at about 12 billion light years from earth.
A gamma-ray burst that swept through our solar system late last year was the brightest ever recorded. (NASA/Reuters)

Scientists have analysed the brightest gamma-ray burst (GRB) ever recorded, which swept through our solar system late last year – overwhelming gamma-ray detectors on satellites.

Scientists believe that the blast may have been the ‘birth cry’ of a black hole.

On 9 October 2022, an intense pulse of gamma-ray radiation hit our solar system, dubbed GRB 221009A for its discovery date, turned out to be the brightest GRB ever recorded.

The explosion, in a distant galaxy 2.4 billion light-years from Earth, represents the collapse of a star many times the mass of our sun, astronomers believe.

GRB GRB221009A was first detected by orbiting X-ray and gamma-ray telescopes.

Read more: What are fast radio bursts, and why do they look like aliens?

Observations of GRB 221009A spanning from radio waves to gamma-rays, including critical millimetre-wave observations with the Center for Astrophysics | Harvard & Smithsonian's Submillimeter Array (SMA) in Hawaii, have now new light on the decades-long quest to understand the origin of these extreme cosmic explosions.

The gamma-ray emission from GRB 221009A lasted more than 300 seconds.

Astronomers think that such "long-duration" GRBs are the birth cry of a black hole, formed as the core of a massive and rapidly spinning star collapses under its own weight.

The newborn black hole launches powerful jets of plasma at near the speed of light, which pierce through the collapsing star and shine in gamma-rays.

Read more: Telescope detects 100 mysterious radio signals from billions of light years away

Lead author Tanmoy Laskar, assistant professor of physics and astronomy at the University of Utah, said: "As the jets slam into gas surrounding the dying star, they produce a bright 'afterglow' of light across the entire spectrum.

"The afterglow fades quite rapidly, which means we have to be quick and nimble in capturing the light before it disappears, taking its secrets with it."

Edo Berger, professor of astronomy at Harvard University and the CfA said: "This burst, being so bright, provided a unique opportunity to explore the detailed behaviour and evolution of an afterglow with unprecedented detail — we did not want to miss it."

"I have been studying these events for more than 20 years, and this one was as exciting as the first GRB I ever observed."

After analysing and combining the data from the SMA and other telescopes all over the world, the astronomers were flummoxed: the millimetre and radio wave measurements were much brighter than expected based on the visible and X-ray light.

"This is one of the most detailed datasets we have ever collected, and it is clear that the millimetre and radio data just don't behave as expected," said CfA research associate Yvette Cendes.

"A few GRBs in the past have shown a brief excess of millimetre and radio emission that is thought to be the signature of a shockwave in the jet itself, but in GRB 221009A the excess emission behaves quite differently than in these past cases."

She added: "It is likely that we have discovered a completely new mechanism to produce excess millimetre and radio waves."

Watch: Ultra-massive black hole 30 billion times the size of our sun is found