Scientists have detected the most powerful flare ever recorded from a supermassive black hole — a cosmic explosion believed to have been triggered when the black hole tore apart and consumed a massive star that ventured too close.
At its brightest, the flare was an astonishing 10 trillion times more luminous than the Sun, unleashed by a black hole about 300 million times the Sun’s mass, located roughly 11 billion light-years away from Earth.
Black holes are regions of extreme density with gravity so intense that even light cannot escape. Most galaxies, including our Milky Way, harbor such giants at their centers. The black hole behind this event is vastly larger than the Milky Way’s central one, which contains about 4 million solar masses.
According to the researchers, the flare was most likely caused by a massive star being drawn into the black hole’s gravitational grip. As the doomed star’s material spiraled inward, it emitted a burst of intense radiation upon reaching the black hole’s “point of no return.”
The star was estimated to be between 30 and 200 times the mass of the Sun. Scientists believe it may have been part of a cluster orbiting near the black hole and was knocked off course following an interaction with another massive object.
“It seems reasonable that it was involved in a collision with another, more massive body in its original orbit around the supermassive black hole, which essentially knocked it inward,” explained Caltech astronomer Matthew Graham, lead author of the study published in Nature Astronomy. “It was placed on a highly elliptical orbit that brought it dangerously close — too close — to the black hole.”
When the star approached the black hole, it was “spaghettified” — stretched and torn apart by immense tidal forces. The shredded material spiraled around the black hole, heating up and glowing brilliantly before vanishing into the void, said study co-author K.E. Saavik Ford of the City University of New York.
Such massive stars are exceptionally rare, as smaller stars are more common and giant ones live short, violent lives. Researchers also suggest that stars orbiting near supermassive black holes can grow unusually large by accumulating gas and dust drawn in by the black hole’s gravity.
The event was monitored using telescopes in California, Arizona, and Hawaii. Scientists ruled out other explanations such as a supernova, a jet from the black hole, or gravitational lensing, concluding that the data matched only a star being destroyed by a black hole.
Because the flare originated 11 billion light-years away, astronomers are observing an event that took place when the universe was less than a quarter of its current age.
The flare brightened 40-fold during the observation period, reaching its peak in June 2018, and was 30 times more luminous than any previous black hole flare ever seen. Although it continues to fade, researchers expect the entire event to span about 11 years in total.
“The flare is still fading,” Graham confirmed.
