Astronomers have identified the largest cosmic explosion ever observed | Space news

The explosion – AT2021lwx – was a fireball 100 times the size of our solar system and 10 times brighter than a supernova.

Astronomers have identified the largest cosmic explosion ever observed, a fireball 100 times the size of our solar system that suddenly started burning in the distant universe three years ago.

While astronomers believe that is the most likely explanation for Friday’s explosion, they stress that more research is needed to understand the puzzling phenomenon.

The explosion, known as AT2021lwx, has now lasted more than three years, compared with most supernovae, which are visible for only a few months, according to the study published in the Monthly Notices of the Royal Astronomical Society.

Led by the University of Southampton, astronomers believe the explosion was the result of a massive gas cloud, perhaps thousands of times larger than our Sun, that was violently disrupted by a supermassive black hole.

According to the study, the explosion took place almost 8 billion light-years away, the universe is about 6 billion years old and is still detectable by a network of telescopes.

Such events are extremely rare and nothing on this scale has been seen before, researchers say.

Last year, astronomers saw the brightest burst on record — a gamma-ray burst called GRB 221009A, nicknamed BOAT — the brightest of all time.

Although the BOAT was brighter than the AT2021lwx, it was only partially sustained, meaning that the overall energy released by the AT2021lwx burst was much higher.

AT2021lwx has earned the nickname „Scary Barbie” from researchers due to its „terrifying potential”.

According to Danny Milisavljevic, an assistant professor of physics and astronomy at Purdue University, AT2021lwx was originally assigned a random alphanumeric name when it was discovered: ZTF20abrbeie. The „Scary Barbie” nickname comes from its alphanumeric designation „abrbeie” and „scary”.

We originally thought AT2021lwx or ZTF20abrbeie #ScaryBarbie A superluminous supernova from a massive star. But to date no theoretical models have come close to explaining the terrifying energy output that continues. A supermassive black hole seems the only solution. pic.twitter.com/GldfFWltJc

— Dany Milsavljevic (@astro_dan_mil) April 26, 2023

AT2021lwx was first detected in 2020 by the Zwicky Transient Facility in California and later picked up by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) in Hawaii.

But the extent of the explosion is not yet known.

Philip Wiseman, a research fellow at the University of Southampton who led the research, said: “Most supernovae and tidal disruption events only last for a couple of months before fading away. A bright two years is immediately very unusual.

It was only when astronomers including Weissmann looked at it with more powerful telescopes that they realized they had it on their hands. By analyzing different wavelengths of light, they found that the explosion was about 8 billion light-years away. It’s farther away than other new flashes in the sky, which means the explosion behind it must be much bigger.

It is estimated to be 2 trillion times brighter than the Sun, Wiseman said.

Astronomers have explored several possible explanations. For one thing, AT2021lwx is an exploding star — but the flash is 10 times brighter than the „supernova” seen before.

Another possibility is when a star is absorbed into a supermassive black hole and is torn apart, in what is known as a tidal disruption event. But AT2021lwx is still three times brighter than those events and Wiseman said their research does not point in this direction.

The only somewhat comparable bright cosmic event is a quasar, which occurs when supermassive black holes at the center of galaxies swallow large amounts of gas. But they glow in brightness, Wiseman said, whereas AT2021lwx, which suddenly started burning from nothing three years ago, is still burning.

„This thing is something we’ve never seen before — it came out of nowhere,” Wiseman said.

Now that astronomers know what to look for, they search the sky to see if they missed other similar explosions.