'We don't know why it's so big,' says astronomer
Astronomers have detected the biggest explosion ever seen in the universe.
The vast blast came from a supermassive black hole and left a crater so big that it could hold 15 Milky Ways, according to the researchers behind the discovery.
Astronomers are unable to explain why the explosion was quite so powerful.
The explosion was detected from a galaxy 390 million lightyears away, and was five times bigger than the previous record-holder.
"We've seen outbursts in the centres of galaxies before but this one is really, really massive," said Melanie Johnston-Hollitt, from the Curtin University node of the International Centre for Radio Astronomy Research.
Mystic Mountain, a pillar of gas and dust standing at three-light-years tall, bursting with jets of gas flom fledgling stars buried within, was captured by Nasa's Hubble Space Telelscope in February 2010. Nasa/ESA/STScI
"And we don't know why it's so big.
"But it happened very slowly – like an explosion in slow motion that took place over hundreds of millions of years."
Astronomers used NASA's Chandra X-Ray Observatory to make the discovery, along with a European space observatory and ground telescopes. They believe the explosion came from the heart of the Ophiuchus cluster of thousands of galaxies: a large galaxy at the center contains a colossal black hole.
Black holes don't just draw matter in. They also blast out jets of material and energy.
The first hint of this giant explosion actually came in 2016. Chandra images of the Ophiuchus galaxy cluster revealed an unusual curved edge, but scientists ruled out an eruption given the amount of energy that would have been needed to carve out such a large cavity in the gas.
The two space observatories, along with radio data from telescopes in Australia and India, confirmed that the curvature was, indeed, part of a cavity.
"The radio data fit inside the X-rays like a hand in a glove," co-author Maxim Markevitch of NASA's Goddard Space Flight Center in Maryland, said in a statement. "This is the clincher that tells us an eruption of unprecedented size occurred here."
The blast is believed to be over by now: There are no signs of jets currently shooting from the black hole.
More observations are needed in other wavelengths to better understand what occurred, according to the team.
The findings appeared in the Astrophysical Journal.