Scientists report largest black hole flare ever seen, with light from 10 trillion suns

A supermassive black hole violently engulfed a huge star, producing a cosmic explosion with the light of 10 trillion suns, a new study suggests.

The black hole eruption, as the phenomenon is called, is considered the largest and most distant ever recorded: it was detected 10 billion light years away.

“This is actually a one-in-a-million object,” said Matthew Graham, a research professor of astronomy at the California Institute of Technology and lead author of the study, published Tuesday in the journal Nature Astronomy.

Graham said a black hole eruption is the most likely explanation, based on the intensity and duration of the explosion, but follow-up studies will help researchers confirm their findings.

It’s not unusual for black holes to consume nearby stars, gas, dust and other forms of matter, but such a gargantuan flaring phenomenon is extremely rare, Graham said.

“This massive flare is far more energetic than anything we’ve ever seen before,” he said, adding that at its peak, the explosion was 30 times brighter than any previous black hole flare seen to date.

Part of the intensity came from the sheer size of the two cosmic objects involved. The unfortunate star that got too close to the black hole is estimated to have at least 30 times the mass of the sun. The enormous black hole and the disk of matter surrounding it are estimated to be 500 million times more massive than the sun.

This strong explosion has been going on for more than seven years, Graham said, and it’s probably still happening.

The flare was first detected in 2018 during an extensive survey of the sky using three ground-based telescopes. At the time, Graham said, it was recorded as a “particularly bright object,” but in follow-up observations months later, scientists were unable to obtain much useful information.

As such, the black hole eruption was largely forgotten until 2023, when Graham and his colleagues decided to revisit intriguing points of interest from their previous investigation. This time, astronomers performed a rough calculation of the distance to the particularly bright object they had seen, and the result shocked them.

“Suddenly it was, ‘Oh, that’s actually pretty far away,'” Graham said. “And if it’s so far away and so bright, how much energy is emitted? Now that’s something unusual and very interesting.”

It’s not yet clear how exactly the star met its demise, but Graham said a case of cosmic bumper cars could have jostled the star and knocked it out of its regular orbit around the black hole, causing this close encounter.

The results help provide a more complete picture of black hole behavior and evolution.

“Our idea of ​​supermassive black holes and their environments has really changed over the last five to 10 years,” Graham said. “There was this classic picture that most galaxies in the universe have a supermassive black hole in the middle and it just sits there and bubbles and that’s it. Now we know it’s a much more dynamic environment and we’re only starting to scratch the surface.”

The flare has gradually subsided over time, he said, but it will likely continue to be observable with ground-based telescopes for a few years.