Black Hole ‘Superflare’ Is the Strongest Ever Seen

Record-breaking black hole explosion reveals star’s final moments

By Jenna Ahart & Nature Magazine

Black holes can get an energy boost by “snacking,” although their meal of choice is quite different from ours. The analysis suggests that the brightest burst of light ever detected from a black hole – a firework that was, at its peak, more than 10 trillion times brighter than the Sun – ignited when the black hole engulfed a star at least 30 times more massive than the Sun.

The results were published on November 4 in Natural astronomy.

When astronomers first laid eyes on the object in 2018, they didn’t realize it was a superflare. After noticing the object brightening, researchers focused on it with Palomar Observatory’s 200-inch Hale telescope. But a graph of the light emitted by the object proved disappointing. “It didn’t seem as interesting as we thought,” says Matthew Graham, an astronomer at the California Institute of Technology in Pasadena and co-author of the paper.

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However, in 2023, the team noticed that even after five years, the black hole remained particularly bright. So they took a closer look using the WM Keck Observatory in Hawaii, which revealed that the object was about 3 million kiloparsecs away, or 10 billion light years away. To appear so bright at such a great distance, the jets of light must have been particularly bright. Astronomers now say the flare is 30 times brighter than any previously detected flash of light from a black hole.

Something about light?

The authors studied several possible causes of this rash. Perhaps there was a supernova near the black hole, or the flare was just an illusion of light, appearing much brighter than it actually was due to the warping effects of gravity. But the team found that neither explanation matched the observations well.

According to the authors, their main theory is that a massive star met its doom by moving too close to the black hole. When the black hole’s gravity tore the star apart, its jets of light burst out about 40 times brighter than before. The team also believes that because the flare has not yet completely disappeared, the star has not yet been completely consumed.

As astronomers continue to observe the star’s disappearance, Joseph Michail, an astronomer at the Harvard and Smithsonian Center for Astrophysics in Cambridge, Massachusetts, wants to see whether the jets will gradually diminish, or perhaps ignite again when light hits the surrounding gas and dust. He also believes that future surveys of the sky could soon allow researchers to find many more beacons like this one. “These events will probably become normal,” Michail says.

Graham thinks that if astronomers want to fully understand these mysterious flares, they will have to keep their eyes glued to the sky for some time to come. This black hole is so far from the solar system that it takes about seven Earth years to witness just two years of black hole activity. Astronomers can actually watch the black hole devour the star at just a quarter speed. To watch more of these events in their entirety, “it’s going to be a very long game,” Graham says.

This article is reproduced with permission and has been published for the first time on November 4, 2025.

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