Astronomers have captured the largest cosmic explosion ever witnessed in a huge world first.
Traced back to eight billion light years away, the flare-up has lasted more than three years so far – and is more than 10 times brighter than any known star explosion ever recorded before.
It was so amazing that Southampton University astronomer Dr Philip Wiseman – who led the observations into the explosion – told BBC News his team’s first response was: “Oh my God, this is outrageous!”
The explosion, known by the catchy moniker AT2021lwx, is not the brightest phenomenon ever seen though – that happened last year and lasted for just 10 hours.
This observation is significant because it has lasted so much longer, signifying more overall energy has been released.
But scientists actually didn’t spot this explosion for quite some time.
Dr Wiseman explained that the explosion “went unnoticed for a year as it gradually got brighter”.
The explosion was first spotted in 2020 by the Zwicky Transient Facility in California,which watches the night sky for supernovae (exploding stars), asteroids or comets.
But it was only a year later when they looked at it again, and they realised how far away it was, that they realised they were looking at something of jaw-dropping magnitude.
Dr Wiseman said: “When I told our team the numbers they were all just so shocked. Once we understood how extremely bright it was, we had to come up with a way to explain it.”
It’s thought the explosion was caused by a vast gas cloud, potentially thousands of times larger than the sun, being sucked into a supermassive black hole.
The gas itself may have come from the large dusty “doughnut” which is usually around black holes, and which may have been pushed into the hole itself.
But this explosion was outside the plausible range for a supernova (they normally only last a few months).
So astronomers thought it might be a tidal disruption event which causes bright flashes in the sky. That’s usually when a star gets too close to a black hole, half of it is shredded and the other half is stretched out.
But Dr Wiseman explained: “Encountering such a huge star is very rare, so we think a much larger cloud of gas is more likely.”
He continued: “We’ve estimated it’s a fireball 100 times the size of the solar system with a brightness about two trillion times the sun’s.
“In three years, this event has released about 100 times as much energy as the sun will in its 10 billion-year lifetime.”
His team are now looking to collect more data on the explosion, looking at different wavelengths to uncover the object’s temperature and processes at the surface.
Details of the discovery were published in the Monthly Notices of the Royal Astronomical Society.