Scientists have detected the biggest explosion in space since the Big Bang - but what was it?
The biggest explosion in the universe since the Big Bang has been discovered by astronomers.
The blast is thought to have come from a supermassive black hole in the Ophiuchus galaxy cluster about 390 million light years from earth.
The eruption, which is said to have released five times more energy than anything witnessed before, left a giant dent in the galaxy cluster.
Professor Melanie Johnston-Hollitt, from the International Centre for Radio Astronomy Research, said, "This is the most energetic outburst we have seen since the Big Bang.
"We've seen outbursts in the centres of galaxies before but this one is really, really massive. But it happened very slowly - like an explosion in slow motion that took place over hundreds of millions of years."
Blast happened between 240 million and 400 million years ago
Prof Johnston-Hollitt said the blast is thought to have happened between 240 million and 400 million years ago.
According to the BBC, scientists had long thought there was something strange about the Ophiuchus galaxy cluster, which is a giant group of thousands of individual galaxies intermingled with hot gas (plasma) and dark matter.
US and European X-ray telescopes had spied a curious curved edge to it.
The speculation was that this might be the wall of a cavity that had been sculpted in its plasma by emissions from a gargantuan black hole in one of the core galaxies.
Scientists initially dismissed black hole theory
Scientists initially dismissed the black hole explanation, however, because the cavity was so big and implied that the black hole emission would have to have been unimaginably large.
Astronomers only realised what had happened when they looked at the Ophiuchus galaxy cluster with four radio telescopes, including the Murchison Widefield Array (MWA) in Western Australia and the Giant Metrewave Radio Telescope (GMRT) in India.
Professor Johnston-Hollitt said the finding is likely to be the first of many.
"We made this discovery with phase one of the MWA, when the telescope had 2,048 antennas pointed towards the sky," she said.
"We're soon going to be gathering observations with 4,096 antennas, which should be 10 times more sensitive. I think that's pretty exciting."