Observed the largest explosion in space, and it is a colossal conundrum
Astronomers said on Friday they had identified the "largest" cosmic explosion ever observed, a fireball 100 times the size of our Solar System that suddenly started flaring up in the distant universe more than three years ago and continues to spew energy .
While offering what they believe is the most likely explanation for the explosion, the astronomers stressed that more research is needed to understand the puzzling phenomenon.
The explosion, dubbed AT2021lwx, isn't the brightest flash ever observed in the universe, but rather a sustained blaze. For instantaneous lightning, the record is still held by a gamma-ray burst that occurred in October and dubbed BOAT (Brightest Of All Time).
Philip Wiseman, an astrophysicist at the UK's University of Southampton and lead author of a new study, said AT2021lwx is considered the " largest " explosion because it has released far more energy over the past three years than BOAT's brief burst produced.
Wiseman told AFP that it was an " accidental discovery ".
The Zwicky Transient Facility in California first spotted AT2021lwx during an automated sweep of the sky in 2020, but it "basically sat in a database," hidden away and unnoticed, until it was recorded by humans the year next, Wiseman said.
Only when astronomers, including Wiseman, looked at it with more powerful telescopes did they realize what they had on their hands.
By analyzing the different wavelengths of light, they figured out that the explosion was about eight billion light-years away.
That's a much greater distance than most of the other new flashes of light in the sky, meaning the explosion behind it must be much bigger.
It is estimated that it is about two trillion times brighter than the Sun and the problem is to explain this phenomenon.
- One possible cause 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. But AT2021lwx is still three times brighter than these events, and Wiseman said his research doesn't point in that direction.
The only somewhat comparable bright cosmic event is a quasar, when supermassive black holes gobble up huge amounts of gas at the centers of galaxies. But these tend to flicker in their brightness, Wiseman recalled, while AT2021lwx suddenly started glowing out of nowhere three years ago, and is still blasting, constantly.
“We've never seen this thing before—it just came out of nowhere,” Wiseman said.
An absolute brain teaser
In the new study, published in the journal Monthly Notices of the Royal Astronomical Society, the international team of researchers outlined what they believe is the most likely scenario.
Their theory is that a single huge cloud of gas – about 5,000 times the size of the Sun – is slowly being consumed by a supermassive black hole.
But Wiseman said that "in science there is never certainty." The team is working on new simulations to test whether their theory is "fully plausible". Scientific certainty exists only on TV and in the heads of journalists.
One problem could be that supermassive black holes are found in the centers of galaxies: for an explosion of this size, the galaxy should be as large as the Milky Way, but no one has been able to detect a galaxy in the vicinity of AT2021lwx.
In short, we are facing a real puzzle of space. Now that astronomers know what to look for, they are scouring the skies to see if other similar explosions have escaped, in order to create a minimal series that allows to identify an explanation for the phenomenon.
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The article Observed the largest explosion in space, and it's a colossal enigma comes from Economic Scenarios .
This is a machine translation of a post published on Scenari Economici at the URL https://scenarieconomici.it/osservata-la-piu-grande-esplosione-nello-spazio-ed-e-un-colossale-enigma/ on Sun, 14 May 2023 13:50:37 +0000.