This week, astronomers confirmed that they had found the oldest known black hole, thanks to the James Webb Space Telescope (JWST) and the Chandra X-ray Observatory. The supermassive black hole formed when the universe was still a toddler, just 470 million years after the Big Bang. But its age isn’t the only thing that makes it unusual.
Astronomers long thought that the only way a black hole could form was through the collapse of a star. But this week’s discovery confirms a theory that some black holes at this early stage in the universe formed from the condensation of clouds of gas. The theory purports that such black holes would produce superheated x-ray-emitting gas. Now, data from JWST and Chandra have helped confirm these x-ray signals from the newly discovered black hole. The findings are available via preprint and have been published in the journal Nature Astronomy.
Ira sits down with Dr. Priyamvada Natarajan, a professor of astronomy and physics at Yale who helped develop this theory, to talk about how these unique black holes change our understanding of the early universe.
- Read Dr. Priyamvada Natarajan’s responses to FAQs about black holes via Space.com.
Priyamvada Natarajan is a theoretical astrophysicist and author of Mapping the Heavens: The Radical Scientific Ideas The Reveal The Cosmos (Yale University Press, 2016). She’s a professor in the departments of physics and astronomy at Yale University in New Haven, Connecticut.
IRA FLATOW: This is Science Friday. I’m Ira Flatow. It’s time to talk about one of my favorite subjects on this show, black holes. Because there is really some intriguing news about a discovery reported this week. Astronomers confirmed that they had found the most distant black hole by X-ray telescope, a supermassive black hole formed when the universe was just a toddler, just 470 million years after the Big Bang.
And what makes this discovery so cool is the size and origin of this black hole. It’s super massive. And its existence confirms a theory that the earliest, most massive black holes, called seed black holes, did not form from the collapse of dying stars, the usual way we think of black hole formation, no, but through the condensation of clouds of gas.
Wow, this is exciting. I want to find out more. So joining me is an astronomer who helped formulate and publicize this idea in 2017. And she’s no stranger to our show, Dr. Priya Natarajan.
PRIYA NATARAJAN: Delighted to be here, Ira.
IRA FLATOW: Are you excited by this?
PRIYA NATARAJAN: Very excited, because for me, it’s things have come full circle. This has been an idea that theoretically we proposed in 2005, 2006. It was considered a bit crazy and speculative, slowly kind of marched along building up. And then we got to the stage of making concrete predictions in 2017, as you mentioned. And then bam, we find this object.
IRA FLATOW: Well, tell us. Tell us what makes this discovery unique.
PRIYA NATARAJAN: So what is really unique about this X-ray quasar is the simultaneous detection by James Webb Space Telescope and Chandra. So I think we believe that there may be only one reliable pathway, as you mentioned in the opening, to make the first black holes, the seeds, and from the death of the first stars. And that would make light seed black holes.
But that would be a challenge for these light seeds to grow into even a million or 10 million times the mass of the sun so early on in the universe like 470 million years. So it was speculated there ought to be other pathways to make seeds, heavier seeds from the get-go.
And so in the early universe, we worked out a scenario where you could potentially form heavy seeds from direct collapse by gravity of gas into protogalaxies. And this object has a mass that is about 10 million times roughly the mass of our sun. And it’s roughly 10 times more massive than the black hole at the center of the Milky Way.
And what is special here is the relationship between the mass of this black hole and the stars in this galaxy UHZ1. In the Milky Way, for example, the stars vastly outweigh the black hole. Even though the black hole dominates the gravity right around the center of our galaxy, stars really kind of outweigh the black hole. And they outweigh by 4 orders of magnitude in the Milky Way.
But for this outsized black hole galaxy, the stars are only roughly maybe 10 times more massive, roughly, than the black hole. And this is predicted if the original seed from which this black hole that we detect came from started life as a heavy seed 10 to the 4 times the mass of the sun.
IRA FLATOW: Right. Right. So how does this change how astronomers think about our early universe?
PRIYA NATARAJAN: Well, I mean, I think what it does, it shows us that there is more than one pathway to make the first black hole seeds. So universe appears to be littered with black holes of all sizes and everywhere, early universe, middle-aged universe, late universe. And so the fact that this is the first evidence that ratifies that one new additional channel to make black holes is really important because it completely changes the game in understanding how these objects formed.
And we know that they form in tandem somehow with the assembly of galaxies. And there are correlations in the properties of the black holes and that all of this action starts really early on. So I think it’s kind of resetting the clock on our expectations for when the first stars and the first black holes form.
IRA FLATOW: Well, Priya, I want to congratulate you and your fellow astronomers and astrophysicists for this exciting discovery. I can see you’re a little more than just excited about this.
PRIYA NATARAJAN: Very excited. Yes. You can’t get me to stop talking about it. And I think what is really cool is this object was actually found behind a kind of object that I also love and work on, which is galaxy clusters that have a lot of dark matter. And they behave like magnifying lenses.
IRA FLATOW: Wow.
PRIYA NATARAJAN: This object was found by good old Chandra. What a wonderful telescope. The X-ray telescope is 20-plus years old. It’s going strong. And so to have my two interests kind of collide in this beautiful way is just a dream.
IRA FLATOW: It’s a dream. It’s a dream to have you on, Priya. Thank you for taking time to be with us today.
PRIYA NATARAJAN: Thank you.
IRA FLATOW: Dr. Priya Natarajan, professor in the Department of Astronomy and Physics at Yale University in New Haven, Connecticut.