Leading Yale astrophysicist Priyamvada Natarajan has proven that black holes can be formed by unstable gas. Now she is looking into the invisible universe using new techniques.
In popular imagination and science fiction, black holes are places of intense gravity, a bit like cosmic vacuum cleaners that suck up everything around us. They form when stars explode, become supernovas, and leave behind deep holes in the fabric of the universe. This phenomenon is difficult to understand, even for Priyamvada Natarajan, a professor of astronomy and physics at Yale University, who has studied the phenomenon for decades.
In 2006, Natarajan proposed a radically different idea about how black holes formed in the early universe. Not through the explosion of a star, but through the direct collapse of gas. She hypothesized that gas in the early universe became unstable and flowed into the center very quickly, like pulling a plug in a bathtub. This bathtub action created massive black holes, up to 10,000 times the mass of the Sun, in the blink of an eye. In late 2023, two space telescopes proved all her predictions and theory correct. Today, we know about direct collapse black holes and about UHZ1, an ancient galaxy that has this thanks to it.
We catch up with her at the Indiaspora 2026 conference in Bengaluru to understand her fascination with invisible space, the competition for space telescopes, and how artificial intelligence is reshaping her work as an astrophysicist. Edited excerpts:
Until now, we have assumed that stars explode, go supernova, and then leave behind black holes a few times the mass of the Sun. Why were you looking for another way for black holes to form in the universe?
We needed to think of another way of how black holes formed rather than stars exploding because we were seeing massive black holes a million times the size of the Sun in the early universe and we had no explanation for that.
My calculations showed that in the early universe, massive black holes could have formed through bathtub motion as gas became unstable and stars began streaming into the center very quickly. Thanks to advanced computers, we were able to build a concrete prediction in 2017 that theorized exactly what observations of the real universe would look like if this type of black hole existed.
Your prediction is based on data that can be observed with the largest telescopes available to you at that time. James Webb, 1.5 million kilometers away in space, observing the infrared spectrum to see the early universe. The Chandra X-ray Observatory is located in low Earth orbit and monitors X-ray emissions. Why do you need these two observations to prove your prediction?
When gas heats up and glows around the black hole’s event horizon, it can be seen in X-ray, optical, or ultraviolet rays. Seeing X-ray emissions from the center of a galaxy is often a good sign that a black hole is there.
However, something that was optically emitted very early in the universe would be seen today in the mid-infrared range as the wavelength of light has been stretched by the expansion of our universe. James Webb has cameras that detect infrared radiation. Our prediction was that for these black holes to form in the early universe, they would have to be seen not only in X-rays, but also in infrared. Therefore, the same black hole had to be seen by Chandra X and James Webb simultaneously to prove our theory that black holes can form in this way.
We predicted six different unique properties, the spectrum, the amount of energy emitted, and even the shape. Only if the six were satisfied with an object could you clearly say that there was convincing evidence that this was a new way for black holes to arise.
There are a total of four space telescopes available to humanity. How did you convince two of them to look in the same direction as the universe to prove your prediction of black hole formation?
As scientists, you compete with each other to assign data to these telescopes. You submit your proposal and it is evaluated anonymously by your peers. The most interesting idea wins. For our prediction, we needed James Webb to look in the same direction for several hours, but with Chandra, we needed several days of observation because it picks up faint, distant objects. When the black hole we predicted was found, Chandra was recording the same patch of sky for 24 days.
I’ve been thinking about the possible black hole idea of the early universe for 20 years. In November 2023, all six predictions were confirmed by data from both James Webb and Charles. How did you feel after this verification?
It was unbelievable. My lab partner sent me the real universe data but joked that it was one of the models we had developed. I fell in love with this joke because the data was very similar to one of the models we expected. This rare moment when everything falls into place is almost magical. I think I cried, because it’s every scientist’s dream to see something they predicted mathematically be proven with real data. And for this to happen in their lives.
Does the differently created black hole you discovered bear your name?
(Laughs) It’s called UHZ1 but it will be there on my epitaph.
What surprised you most in the aftermath?
The kind of appreciation I received for the work was completely unexpected. Astrophysics awards and fellowships were expected, but there was significant media interest. I was on the TIME 100 list of the most influential people in the world, an email that I thought was spam. But I was already busy publishing more papers and having my work reviewed by my colleagues.
You work on the invisible universe, dark matter, dark energy and black holes. One cannot see or photograph these entities. What is magic and how do you deduce its existence?
Light is our cosmic messenger, but dark matter or dark energy does not interact with light at all. Their visual absence means they are physically present. I find it intellectually very attractive because you have to look at these things indirectly to infer things about them, to understand their nature. It’s like detective work.
Dark matter, which I currently study, deflects light. Light rays travel through the fabric of the universe, going up and down matter and dark matter, creating kinks or craters in this fabric. We physicists record the signatures of diffracted light to understand dark matter. In the case of black holes, only light outside the event horizon is absorbed. Anywhere outside the event horizon, you can receive signals and radiation. For example, when gas is drawn into a black hole, it heats up on its way before it reaches the event horizon. It shines. This is how we see, measure and map the study of black holes.
How have the last two decades of astrophysics added to our understanding of black holes at the center of galaxies?
Because black holes can affect the fabric of the universe, most black holes, especially supermassive black holes with a mass greater than a million times the mass of the Sun, are found at the center of most, if not all, galaxies. The last two decades have given us a new understanding of how black holes play a very important role in shaping the galaxies in which they are located. Black holes heat the gas before it crosses the event horizon. This is interesting because the gas must cool, become dense and form a substance. In this way, the black hole acts as a switch that turns the star formation process on and off. They control visible matter in the galaxy from stars to planets.
What are you working on now?
I’m exploring how dark matter interacts with black holes as they appear to exist at the centers of galaxies. Another direction I’m exploring is what explains dark energy, which is not yet understood but is responsible for the rapid expansion of our universe. Both are open-ended questions.
How has technology helped the Advanced, such as telescopes and now artificial intelligence, astrophysics?
New developments in charge-coupled instruments that use a highly sensitive silicon chip detector to capture the light are allowing us more detailed images of faint and distant celestial objects. In space telescopes, weight matters, so making the visualization components lighter and more compact is important. Recently, graphics processing units have accelerated our computational capabilities. Many of the simulations would have taken a year to run on a supercomputer. Now we can simulate thousands of possible scenarios together.
She feels that AI could fundamentally shift the nature of discovery. Why?
The big LLM models have absorbed everything that’s been published in our area, haven’t they? So they come armed with experience in peer-reviewed published materials. Can an AI agent interrogate a new idea more thoroughly than a group of scientists? Can it identify our blind spots? Could he become a peer reviewer in the future? Could this actually work in the lab, right in the chaos of science? Can AI write a scientific paper from beginning to end, generating the idea, developing it, and writing it in a coherent manner? We are certainly in a time of exciting intellectual upheaval. We did not fully realize how artificial intelligence would change all dimensions of our reality.
