A Single, ‘Naked’ Black Hole Rewrites the History of the Universe
A supersize black hole — seen three times in this JWST image — mysteriously appears in the early universe without a galaxy surrounding it.
Quanta Magazine; source: JWST/NASA/ESA/CSA and Lukas Furtak
Introduction
A black hole unlike any seen before has been spotted in the early universe. It’s huge and appears to be essentially on its own, with few stars circling it. The object, which may represent a whole new class of enormous “naked” black holes, upends the textbook understanding of the young universe.
“This is completely off the scale,” said Roberto Maiolino, an astrophysicist at the University of Cambridge who helped reveal the nature of the object in a preprint posted on August 29. “It’s terribly exciting. It’s highly informative.”
“It’s pushing the boundaries on what we think might be true, what we think might happen,” said Dale Kocevski, an astronomer at Colby College who was not involved in the new research.
Astronomers spied the bare black hole using the James Webb Space Telescope (JWST) — a mega-instrument built by NASA and its partners in part to reveal how galaxies formed during the universe’s first billion years. This new black hole, which is as heavy as 50 million suns and is dubbed QSO1, clashes with the old, provisional account of the galaxy formation process, which did not start with black holes. Black holes were thought to have come along only after a galaxy’s stars gravitationally collapsed into black holes that then merged and grew. But Maiolino and his colleagues described a solitary leviathan with no parent galaxy in sight.
The question now is how this black hole came to exist.
The most exciting — and controversial — possibility dates back to a 1971 proposal from the British physicist Stephen Hawking: that black holes arose in the primordial soup of the Big Bang itself. In that case, the object would have been sitting in the dark since the universe’s first moments, waiting for stars and galaxies to illuminate it.
QSO1 is one of hundreds of similar-looking objects nicknamed “little red dots” that JWST has spotted in its first few years of peering into the deepest recesses of time. Astrophysicists can’t say yet whether these dots are all black holes or not, and in general they’re still confused about the universe’s chaotic childhood. But the telescope’s snapshots suggest a rowdy young cosmos that fabricated big black holes and galaxies both together and independently, or maybe even a universe where black holes were among the first large structures in existence — dark tapioca bubbles in an otherwise smoothly blended cosmic tea.
QSO1 and the rest of the little red dots “tell us we don’t know anything,” said John Regan, a theorist at Maynooth University in Ireland. “It has been really exciting and very electrifying for the field.”
Pale Red Dots
Lukas Furtak, an astronomer at Ben-Gurion University in Israel, knew QSO1 was extraordinary the moment he saw it — or the moment he saw its three reflections hiding among a smattering of splotchy white galaxies in an image taken by JWST in 2023. It’s “something that pops out immediately,” Furtak said over Zoom, clicking on three nearly imperceptible red specks. “There are three red point sources here, here, this one up here.”
In the image, a fortuitous placement of galaxies and dark matter has bent light rays traveling from background objects just as a glass lens might; this “gravitational lens” reveals objects deeper in the early universe than the telescope could otherwise see. The lens magnifies and stretches the stuff behind it, sometimes creating multiple images of it. Furtak was mapping out the banana-shaped smears of galaxies that the lens had projected into multiple places when he spotted the three red dots of QSO1.
The dots caught his eye because they show no signs of stretching. He knew that the only thing that looks like a small, round point even after getting stretched out is an even smaller, rounder point. This was no galaxy, he figured; it must be a black hole, a concentration of mass so dense that its gravity creates an inescapable zone of space around it.
Over the next six months, Furtak and collaborators directed JWST to stare at each of the three red dots for 40 hours each to take a census of the colors of light coming from the object, known as a spectrum. That study concluded that QSO1 is very likely a glowing black hole packing a mass of tens of millions of suns into a span of at most 100 light-years across, seen as it appeared when the universe was just 750 million years old. (Today the cosmos is approaching 14 billion years old.)
The James Webb Space Telescope, which launched in 2021, has spotted hundreds of strange black holes and galaxies in the early universe, revealing a chaotic first billion years of cosmic history.
NASA/MSFC/David Higginbotham
QSO1 was one of the first little red dots found. There are now over 300 of them, and a spirited debate over their nature has raged for two years. They have some classic features of glowing black holes, but not others. And estimates of their masses have (until now) been somewhat indirect. As a result, some astrophysicists have argued — as one group did in an analysis of more than 100 little red dots in August — that the objects are really just odd-looking galaxies with no black holes after all.
“The field has been obsessed with them,” Kocevski said. “Very rarely do you find things you can’t explain.”
Zooming In
In December 2024, Maiolino, together with Hannah Übler, now at the Max Planck Institute for Extraterrestrial Physics, and other collaborators, trained JWST on QSO1 for another 10 hours. They zoomed in on the dot until it resolved into a pixelated splotch, and measured the specific colors coming from each pixel. From these spectra, they calculated the speed at which the stuff shining in each pixel was moving toward us or away from us. The scientists found that bright material — likely hot gas — swirled around in a furious vortex, one that backed up Furtak’s preliminary findings.
Their closer look, detailed in a pair of preprints posted in May and August, definitively revealed QSO1’s identity.
One clue was its mass. By reconstructing the vortex, the team directly measured the mass of the object it was orbiting: 50 million times more massive than our sun. This matched what Furtak and his collaborators had found. (This result alone marks a big step forward: It suggests that the simpler indirect mass measurement based on the whole object’s spectrum works for young black holes, which had been a point of contention.)
More than 300 “little red dots” have been seen so far — mysterious objects in the early universe that look like big, glowing black holes in some ways and unusual galaxies in others.
Courtesy of Jorryt Matthee. Data from the EIGER/FRESCO surveys
Moreover, the group found no evidence of a starry galaxy around QSO1. The gas orbits the central pixel just as the Earth orbits the sun — indicating that mass is packed into a point. The team estimates that the black hole makes up at least two-thirds of the mass of QSO1, with the remaining third being gas and perhaps a smattering of stars. Regan, who wasn’t involved in the research, thinks they’re being conservative and that QSO1 could be as much as 90% black hole. “We’ve never seen anything like that before,” he said.
Finally, the pixel-by-pixel spectra also revealed that the gas orbiting the black hole is essentially pure hydrogen, an element that dates back to the Big Bang. Stars shine by fusing hydrogen into heavier atoms, and when stars explode, they scatter those heavier elements everywhere. QSO1 seemingly reached its current form before many nearby stars had lived and died.
“The most plausible explanation seems to be [that] the black hole developed before the galaxy,” said Marta Volonteri, a theorist at the Paris Institute of Astrophysics who helped with the new analysis of QSO1.
Shrouded Origins
A top task for astrophysicists now will be to sort out how QSO1 and its ilk formed, and how they became the supermassive black holes that sit at the centers of starry galaxies today. Supermassive black holes, which can weigh as much as billions of solar masses, can be seen anchoring galaxies by the end of the universe’s first billion years.
Supermassive black holes have long troubled astrophysicists. They know that galaxies can make black holes when their big stars burn and die. Those stellar corpses merge and feed on gas and dust, growing larger. The conventional story is that this growth eventually results in one giant black hole sitting in the center of the galaxy. The problem is that all this feeding and merging takes time, and astrophysicists struggle to imagine it happening fast enough to result in the supermassive black holes seen by the universe’s billion-year mark. So theorists have spent decades coming up with a menu of alternative theories about their formation.
Lukas Furtak, an astronomer at Ben-Gurion University in Israel, immediately spotted QSO1 in a field of bright white galaxies.
Sarah Libanore
Now QSO1, which has no galaxy to speak of, shows that there must indeed be another way.
So how might the universe directly manufacture gigantic black holes? Maiolino’s group favors Hawking’s proposal. The Big Bang produced an infant universe that was denser in some spots than in others. A sufficient density could have collapsed straight into a black hole, which would then have grown by absorbing any matter around it. After hundreds of millions of years, some of these “primordial” black holes might have reached gigantic proportions — appearing much like QSO1.
“It’s the most plausible explanation that I see,” Volonteri said. But “I’m sure in the next six months there will be a thousand people coming out with other theories.”
They won’t have to wait six months. Even before QSO1’s discovery, Priyamvada Natarajan, a theoretical astrophysicist at Yale University, and collaborators had already published two non-primordial theories that could account for QSO1’s origin.
A number of theories could explain the mysterious origin of QSO1. Priyamvada Natarajan, a theorist at Yale University, has helped develop a few of them.
Sasha Maslov for Quanta Magazine
The first theory supposes that the Big Bang produced dense spots that didn’t collapse immediately. Instead, they evolved into clouds of gas over hundreds of thousands of years. Residual radiation from the Big Bang stopped these clouds from cooling and fracturing into stars, letting them become massive enough to collapse straight into black holes. In a paper posted in June, researchers led by Wenzer Qin at New York University called these slightly later-blooming giants “not-quite-primordial” black holes.
Or perhaps QSO1 did come from a galaxy after all — one that quickly formed, made a big black hole, and vanished. In 2014, Natarajan and Tal Alexander of the Weizmann Institute of Science in Israel described a scenario where one star in an especially starry region collapses into a large black hole that then zooms around like Pac-Man, hoovering up gas and ballooning to a huge size. The other early stars then wink out quickly, leaving the giant black hole to its own devices.
None of these origin stories fits QSO1 snugly, though each is possible. The only scenario that’s essentially ruled out is the textbook one of stars collapsing, merging and feeding on an orbiting disk of gas.
QSO1 isn’t the first unconventional black hole spotted by JWST, though it’s the barest one. Another striking find sits in a galaxy called UHZ1, which formed less than half a billion years after the Big Bang. By combining JWST observations with X-rays collected from the object by the Chandra X-ray Observatory in 2022, Natarajan and collaborators determined that UHZ1 is also more black hole than surrounding galaxy. This and a handful of other features led the group to conclude that UHZ1’s black hole was born when a cloud of gas largely skipped the star stage and collapsed directly — a theory that also might work for QSO1.
The challenge — and excitement — for astronomers is that they’re confronting a new era of cosmic history for the first time, and it’s proving tough to make sense of the scene. Regan compares the situation to developing a whole theory of humanity based on adults and teenagers — the adolescent and mature galaxies we could see prior to the launch of JWST. Now observing little red dots is the equivalent of discovering toddlers, messy new entities that are hard for researchers to interpret based on what they’ve seen before. “It’s a different vibe,” he said. “They’re running around like lunatics.”
Editor’s note: Priyamvada Natarajan is a member of Quanta Magazine’s scientific advisory board. She was interviewed for this story but did not otherwise contribute to its production.
