Astronomers have observed the brightest flash of light ever seen, from an event that occurred 2.4 billion light years from Earth and was likely triggered by the formation of a black hole.
The gamma-ray burst – the most intense form of electromagnetic radiation – was first detected by orbiting telescopes on October 9, and its glow is still observed by scientists around the world.
Astrophysicist Brendan O’Connor told AFP that gamma-ray bursts lasting hundreds of seconds, as happened on Sunday, are caused by the deaths of massive stars more than 30 times larger than our sun.
The star explodes in a supernova, collapses into a black hole, then the matter forms in a disk around the black hole, falls inside and is ejected in a jet of energy that travels at 99.99% the speed of light.
The flash released photons carrying a record 18 teraelectron volts of energy – that’s 18 with 12 zeros behind it – and impacted long-wave radio communications in the Earth’s ionosphere.
“It’s really breaking records, both in the number of photons and the energy of the photons that are reaching us,” said O’Connor, who used infrared instruments on the Gemini South telescope in Chile to make new observations on Friday. “Something so bright, so close, is truly a once-in-a-lifetime event,” he added.
– Gamma-ray bursts typically release the same amount of energy that our Sun produces throughout its life in the space of a few seconds – and this event is the brightest gamma-ray burst.
The gamma-ray burst, known as GRB 221009A, was first detected by telescopes including NASA’s Fermi Gamma-ray Space Telescope, Neil Gehrels’ Swift Observatory, and the Wind spacecraft on Sunday morning, Eastern time.
1.9 billion year old film
It originated in the direction of the Sagitta constellation and traveled for about 1.9 billion years to reach Earth, less than the current distance from its starting point, because the universe is expanding.
Watching the event now is like watching a 1.9 billion-year record of these events unfolding before us, giving astronomers a rare opportunity to gain new insights into things like black hole formation.
“That’s what makes this kind of science so compelling – you get this adrenaline rush when these things happen,” said O’Connor, an affiliate of the University of Maryland and George Washington University.
He added that while the initial explosion may have been visible to lucky amateur astronomers, it has since disappeared from view.
In the coming weeks, he and others will continue to examine supernova signatures at optical and infrared wavelengths, to confirm that their assumptions about the origin of the flash are correct and that the event agrees with known physics.
Unfortunately, while the initial explosion may have been visible to amateur astronomers, it has since disappeared.
Supernova explosions are also expected to be responsible for producing heavy elements – such as gold, platinum, uranium – and astronomers will also be looking for their signatures.
Astrophysicists have written in the past that the sheer power of gamma-ray bursts could cause extinction-level events here on Earth.
But O’Connor pointed out that because the jets of energy are very concentrated and are unlikely to emerge in our galaxy, this scenario isn’t something we should worry too much about.
