(Paris) Astronomers on Friday announced the discovery of the “biggest” cosmic explosion ever, a ball of energy a hundred times the size of our solar system that suddenly exploded three years ago.
Posted at 8:09 p.m.
Daniel Lawler Agence France-Presse
Scientists have a new explanation to explain the cause of the phenomenon, but insist on the need to continue research to clarify the matter.
The event, catalog number AT2021lwx, is not the brightest on record. That award goes to gamma-ray burst (a colossal burst of energy from a star’s collapse) GRB221009A, discovered in October 2022 and dubbed “the brightest on record.”
But the blast, described in the monthly notes of Britain’s Royal Astronomical Society, can be called the “biggest” because it released infinitely more energy than the gamma-ray burst in three years, according to the study’s lead author Philip Wiseman, according to astrophysicists at the British University of Southampton.
AT2021lwx is the result of an “accidental discovery,” he told AFP.
The explosion was automatically detected in 2020 by the American observatory Zwicky Transient Facility in California. According to Wiseman, however, this discovery was “stored unused in the observatory’s database.” Before scientists noticed it the following year.
Direct observation of the phenomenon changed the game. Analysis of the light showed that it took eight billion years to reach the telescope.
“A Real Mystery”
Astronomers are still puzzling over the cause of the phenomenon. It could be a supernova, the explosion of a massive star at the end of its life, but the luminosity here is 10 times greater than expected.
Another possibility is a tidal break, where a star is torn apart by the gravitational pull of a black hole it has come too close to. But again, AT2021lwx is three times too bright to confirm such a scenario.
The measured brightness has no known equivalent other than that of quasars. These galaxies harbor a supermassive black hole at their heart that gorges on matter by emitting a phenomenal amount of light.
But the light from the quasars is sparkling, while in this case it suddenly increased three years ago. “We have never observed anything like this […]. It seemed to come out of nowhere,” notes the scientist.
His team has an idea, which is set out in the study. His theory states that a gigantic cloud of gas the size of 5,000 suns is being swallowed up by a supermassive black hole.
Since the tenet of science is that “there are never certainties,” the team is working on new simulations — using the data — to test the “unquestionable plausibility” of their theory.
The problem is that supermassive black holes are said to be at the center of galaxies. And the event AT2021lwx should have a size that corresponds to our Milky Way.
However, no one has yet discovered a galaxy near the observed event. “It’s a real mystery,” says Philip Wiseman.
It remains to search the sky and sky observation databases for similar events that will likely help lift the veil on the blast.