Astronomers yesterday said they have identified the largest cosmic explosion ever observed, a fireball 100 times the size of the solar system that suddenly began blazing in a distant universe more than three years ago.
While the astronomers offered what they think is the most likely explanation for the explosion, they emphasized that more research was needed to understand the puzzling phenomenon.
However, the explosion, called AT2021lwx, was not the brightest flash ever observed in the universe. That record is still held by a gamma-ray burst in October last year that was nicknamed BOAT — for Brightest Of All Time.
Photo: AFP / Sheffield University / Mark A. GARLICK
Philip Wiseman, an astrophysicist at the University of Southampton in England and the lead author of a new study, said that AT2021lwx was considered the largest explosion because it had released far more energy over the past three years than was produced by BOAT’s brief flash.
Wiseman said it was an “accidental discovery.”
The Zwicky Transient Facility in California first spotted AT2021lwx during an automated sweep of the sky in 2020.
However, “it basically sat in a database” until being noticed by scientists the following year, Wiseman said.
It was only when astronomers, including Wiseman, looked at it through more powerful telescopes that they realized what they had on their hands.
By analysing different wavelengths of light, they worked out that the explosion was about 8 billion light years away.
That is much farther away than most other new flashes of light in the sky — which means the explosion behind it must have been far greater.
AT2021lwx was estimated to be about 2 trillion times brighter than the sun, Wiseman said.
Astronomers have looked into several possible explanations.
One is that AT2021lwx is an exploding star — but the flash is 10 times brighter than any previously seen supernova.
Another possibility is what is called a tidal disruption event, when a star is torn apart as it is sucked into a supermassive black hole.
However, AT2021lwx is still three times brighter than those events, and Wiseman said the research did not point in this direction.
The only somewhat comparable bright cosmic event is a quasar, when supermassive black holes swallow huge amounts of gas in the center of galaxies.
However, they tend to flicker in brightness, whereas AT2021lwx suddenly started flaring up from nothing three years ago, and it is still blazing away, Wiseman said
“This thing we have never, ever seen before — it just came out of nowhere,” Wiseman said.
In the new study, published in the Monthly Notices of the Royal Astronomical Society, the international team of researchers laid out what they believe is the most likely scenario.
Their theory is that a massive, single cloud of gas — about 5,000 times larger than the sun — is slowly being consumed by a supermassive black hole.
Wiseman said that “in science, there’s never certainty.”
The astronomers are working on new simulations to see if their theory is “fully plausible,” he added.
One problem could be that supermassive black holes sit in the center of galaxies — for an explosion this size, the galaxy would be expected to be as vast as the Milky Way, Wiseman said.
However, no one has been able to spot a galaxy in the vicinity of AT2021lwx.
“That’s an absolute puzzle,” Wiseman said.
Now that astronomers know what to look for, they are searching the skies to see if other similar explosions have been missed.
POLITICAL PRISONERS VS DEPORTEES: Venezuela’s prosecutor’s office slammed the call by El Salvador’s leader, accusing him of crimes against humanity Salvadoran President Nayib Bukele on Sunday proposed carrying out a prisoner swap with Venezuela, suggesting he would exchange Venezuelan deportees from the US his government has kept imprisoned for what he called “political prisoners” in Venezuela. In a post on X, directed at Venezuelan President Nicolas Maduro, Bukele listed off a number of family members of high-level opposition figures in Venezuela, journalists and activists detained during the South American government’s electoral crackdown last year. “The only reason they are imprisoned is for having opposed you and your electoral fraud,” he wrote to Maduro. “However, I want to propose a humanitarian agreement that
ECONOMIC WORRIES: The ruling PAP faces voters amid concerns that the city-state faces the possibility of a recession and job losses amid Washington’s tariffs Singapore yesterday finalized contestants for its general election on Saturday next week, with the ruling People’s Action Party (PAP) fielding 32 new candidates in the biggest refresh of the party that has ruled the city-state since independence in 1965. The move follows a pledge by Singaporean Prime Minister Lawrence Wong (黃循財), who took office last year and assumed the PAP leadership, to “bring in new blood, new ideas and new energy” to steer the country of 6 million people. His latest shake-up beats that of predecessors Lee Hsien Loong (李顯龍) and Goh Chok Tong (吳作棟), who replaced 24 and 11 politicians respectively
Young women standing idly around a park in Tokyo’s west suggest that a giant statue of Godzilla is not the only attraction for a record number of foreign tourists. Their faces lit by the cold glow of their phones, the women lining Okubo Park are evidence that sex tourism has developed as a dark flipside to the bustling Kabukicho nightlife district. Increasing numbers of foreign men are flocking to the area after seeing videos on social media. One of the women said that the area near Kabukicho, where Godzilla rumbles and belches smoke atop a cinema, has become a “real
‘WATER WARFARE’: A Pakistani official called India’s suspension of a 65-year-old treaty on the sharing of waters from the Indus River ‘a cowardly, illegal move’ Pakistan yesterday canceled visas for Indian nationals, closed its airspace for all Indian-owned or operated airlines, and suspended all trade with India, including to and from any third country. The retaliatory measures follow India’s decision to suspend visas for Pakistani nationals in the aftermath of a deadly attack by shooters in Kashmir that killed 26 people, mostly tourists. The rare attack on civilians shocked and outraged India and prompted calls for action against their country’s archenemy, Pakistan. New Delhi did not publicly produce evidence connecting the attack to its neighbor, but said it had “cross-border” links to Pakistan. Pakistan denied any connection to