Last August, astrophysicist Dale Kocevski submitted a paper to the preprint server arXiv with preliminary data on what the new James Webb Space Telescope (JWST) discovered about black holes during one of its probes into space. Did not predict that JWST would bring a revolutionary view of mysterious celestial objects. “And that turned out to be completely wrong,” says Kocevski, who is based at Colby College in Waterville, Maine.
Weeks after this publication, the floodgates opened. One preprint appeared last September, followed by a cascade of others in recent months3,4,5,6,7,8,9,10,11, announcing the existence of more black holes in the distant universe than astronomers had dreamed of. JWST’s unprecedented power has allowed it to discover a huge variety of these objects from many faint, distant black holes to a handful of bright ones raging even further out.
“It’s really studying parts of the universe that weren’t technologically accessible to us,” says Rebecca Larson, an astrophysicist at the Rochester Institute of Technology in New York.
JWST studies of black holes are still in their early days, and astronomers warn that much remains to be resolved. But it’s already clear that his findings could help scientists answer many long-standing questions about black holes, such as how they managed to form early in the universe’s history and quickly grow into the cosmic vacuum, sucking up everything around them.
Black holes come in several sizes
Black holes come in several sizes, but the ones detected by JWST are massive, weighing millions to billions of times that of the Sun. Astronomers aren’t sure how these black holes form, but it could involve the collapse of massive stars or gas clouds that then start pulling in nearby gas and dust. In this scenario, these black hole “seeds” would grow rapidly until they become the gravitational maw that lurks at the heart of most galaxies.
Black holes aren’t visible themselves their immense gravitational pull means that not even light can escape but they can be spotted by looking for superheated gas swirling around them like water down a drain. Before JWST, astronomers studied black holes using a variety of space and ground-based telescopes. However, these could only detect the brightest black holes, including those relatively close to Earth.
JWST is designed to see light coming from distant space and can see black holes lying further away including ones that astronomers thought would be too faint to detect. In JWST images, these faint black holes appear as small and fairly inconspicuous balls, but “they are clearly distinct” from the galaxies that surround them, says Jorryt Matthee, an astrophysicist at the Swiss Federal Institute of Technology in Zurich.
400 million years after the big bang seeds of black holes
JWST also found some of the most distant black holes ever seen. Group 8’s confirmed record holder sits at the heart of a well-studied galaxy called GN-z11, which has a redshift of 10.6. This suggests that as early as 400 million years after the big bang, the seeds for black holes had already formed and were capable of creating a supermassive object.
The goal of the upcoming observations is to explore the details of how superheated gas flows around GN-z11, which could shed light on how the black hole affects the space around it, says Hannah Übler, an astrophysicist at the University of Cambridge in the UK. Such distant JWST discoveries are consistent with recent simulations of the birth of early black holes, says Raffaella Schneider, an astrophysicist at Sapienza University of Rome.
She and her colleagues discovered that large black holes can form in the early universe if they absorb gas at an incredibly high rate in the early stages14. This would theoretically violate the maximum rate at which black holes can grow. But the JWST observations suggest that some black holes, like the one in GN-z11, could grow this way and that the theory might need revision.