In a flare of light that traveled for 10 billion years to reach us, astronomers have identified the most powerful and most distant blaze of energy ever recorded from a black hole, an eruption whose peak shone with the power of 10 trillion Suns.
The cause of this colossal event, says a team led by astrophysicist Matthew Graham of Caltech, was likely a supermassive black hole 500 million times the mass of the Sun devouring an unlucky star that flew a little too close to the powerful gravity well at the center of a distant galaxy. These black hole feasts are known as tidal disruption events (TDEs).
"The energetics show this object is very far away and very bright," Graham says. "This is unlike any AGN [active galactic nucleus] we've ever seen."
Related: Our Galaxy's Supermassive Black Hole Has Emitted a Mysteriously Bright Flare
The event burst onto the scene in 2018, when the black hole – referred to as J2245+3743 – suddenly and dramatically brightened by a factor of 40 over the course of a few months, building to a peak 30 times brighter than the next most powerful AGN flare seen to date, an event nicknamed "Scary Barbie".
Since reaching its peak, J2245+3743 has been gradually fading, but it has yet to subside to its original brightness.
By the time the researchers submitted their paper in March 2025, the amount of energy released was around 1054 erg – the equivalent of transforming the Sun's entire mass into electromagnetic radiation.
There are a few different cosmic events, aside from TDEs, that can cause sudden flares of light that slowly fade.
The BOAT – or Brightest of All Time, a record that has yet to be beaten – was a gamma-ray burst accompanying a supernova explosion and the birth of a black hole. The kilonova produced by a neutron star collision also fades slowly. And AGNs can flicker and change in brightness due to changes in the flow of material on which the black hole feeds.
Each of these events plays out a certain way. After analyzing the changing light from J2245+3743, Graham and his colleagues determined that its profile best fit a TDE, one where a star around 30 times the mass of the Sun skated too close to the black hole. It would have been rent asunder by the powerful tidal forces at play around the black hole, where a massive disk of material swirls as it feeds into the central object.
This disk, in fact, may be why the star was so large.
"Stars this massive are rare," says astronomer K. E. Saavik Ford of City University of New York, "but we think stars within the disk of an AGN can grow larger. The matter from the disk is dumped onto stars, causing them to grow in mass."
Over time, the black hole has been devouring the disintegrated star; it's still two magnitudes brighter than its pre-flare level. The astronomers believe that the black hole will return to its original brightness once every single morsel of the star has fallen beyond the event horizon.
Here's the really mind-boggling part: Although J2245+3743 has remained brighter than its baseline for more than six years from our perspective, the actual event likely transpired over a much shorter timeframe. The researchers are watching it in slo-mo because of how the expansion of the Universe distorts time.
"It's a phenomenon called cosmological time dilation due to stretching of space and time. As the light travels across expanding space to reach us, its wavelength stretches as does time itself," Graham says. "Seven years here is two years there. We are watching the event play back at quarter speed."
Factoring in time dilation is essential because it helps more accurately model the way a TDE plays out, including how long it actually takes.
This information will help astronomers discover similar events that may be lurking in archives or miscategorized as other types of events. A dedicated reexamination of these events and follow-up observations may bring them out of hiding.
The research has been published in Nature Astronomy.