Texas can lay claim to a lot of records: the tallest highway interchange, the longest leather belt, and now discovery of the oldest black hole in the universe. And no, we’re not talking about the traffic on I-35.
An international team led by UT Austin’s Cosmic Frontier Center announced their discovery last week of the oldest, most distant black hole ever confirmed. The black hole and its galaxy, CAPERS-LRD-z9, are 13.3 billion years old.
Texas Standard spoke with Dr. Anthony Taylor, the postdoctoral researcher at the Cosmic Frontier Center who led the team that made this incredible discovery. Listen to the interview above or read the transcript below.
This transcript has been edited lightly for clarity:
Texas Standard: Tell us about this black hole that you and your team discovered. What makes it so remarkable, and how big are we talking?
Anthony Taylor: This black hole is remarkable because it’s the first definitively confirmed black hole in the very, very early universe. And this black hole is about 10 times the mass of the black hole at the center of our Milky Way Galaxy, so it’s a fairly massive object.
And the really interesting thing about it is that it’s so large, so massive, so early on in the universe’s history. While objects of this size might be fairly common in today’s epochs, those objects have had since the big bang to grow. They’ve had 13.8 billion years to get as big as they are.
However, this black hole is only about 500 million years after the big bang. So, it pushes a lot of interesting questions of how did it get this big that quickly?
This black hole is part of a recently discovered class of galaxies called the Little Red Dots. What makes them so unique?
The Little Red Dots were actually a surprise from the James Webb Space Telescope, or JWST. Before JWST launched, we really had no idea that these objects existed. JWST launched, we started getting early data, and these things popped up everywhere.
And the interesting thing about the Little Red Dots is they are very, very small, compact galaxies. So that instead of being beautiful grand spirals that we like to see in imaging and that we all use as our desktop backgrounds, instead, there are really tiny little specks in the imaging. And they also have a very, very distinctive red coloration to them.
And we started finding these things everywhere. And there was intense debate initially as to what these things are. Are they galaxies with populations of old red stars? Are they instead being driven by active black holes?
And over the last few years, the answer that they are indeed driven by black holes is becoming more and more likely. And objects like CAPERS-LRD-z9, happen to be some of the most extreme examples, especially in terms of how early it is in the universe.
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Is there anything that we’ve learned about the history of the universe from this black hole so far?
Absolutely. So this black hole, because it’s so big so early, it’s challenging some of our models of how black holes are formed and how they grow.
Typically, we like to think of a black hole as being the remnant of a massive star that goes supernova, and it leaves a black hole behind. Then, by devouring gas and dust around it, that black hole can then grow to become the supermassive black holes we see today. However, there’s not enough time in the universe for this black hole to have gotten this big this early, using this traditional growth method and this traditional inception of being from an exploding star.
So there’s a few options there. We either need to have something much more massive than a star that creates this object. This would be what we call a direct collapse method. So perhaps we have a very large cloud of gas that instead of fragmenting and becoming a bunch of small stars, instead slowly, but surely, collapses in on itself to form a black hole.
Or you could have a bunch of small star clusters that all collapse together to form this thing. And under that model, this black hole would start out much more massive than it would if it started from just a star, so it can get a head start and grow at normal rates and become exactly what we see in our data.
The other explanation is we have a star that goes supernova, it leaves behind a black hole, and this black hole instead consumes matter at a much higher rate than our models are used to.
Either one of these scenarios is very, very exciting because they’re challenging what we thought we knew about how black holes grow.
When we’re looking this far back into history, we need a lot of tech. You mentioned the James Webb Telescope. Is that, combined with other technology, what’s really helping make this happen?
That’s really what’s enabled all of this. None of this would be possible without JWST. And there’s a few main reasons for that.
So for objects in the early universe, as the light emitted from those objects travels through the universe to us, the universe has been expanding, so that light gets stretched out. So it would have been optical wavelengths of light — the light we can see with our eyes — wavelengths that are emitted like that from these objects in the earlier universe get stretched into infrared wavelengths.
And the problem is our atmosphere likes to block infrared. And even worse, it likes to emit infrared. So it’s very difficult to do these observations from the ground. Instead, it’s much, much easier to go into space, where space is going to be nice and transparent to allow these wavelengths of light to be received by our telescopes.
The other big factor with JWST is it was designed as a near-infrared to mid-infrared telescope. Hubble is a fantastic telescope. It’s served us for a very long time. But that was designed for UV and optical light. It wasn’t very sensitive to these wavelengths. So since its launch a couple years ago, JWST has really revolutionized our studies of the early universe because it was designed for this.
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What’s next for you and your team? Are you going to dig into some of these questions that you posed? Or are you looking for the next biggest black hole, or all of the above?
Actually, yes, all of the above. I think there’s a lot more work to be done on CAPERS-LRD-z9. It’s an interesting object in its own right. And we’d love to get additional data from JWST at higher resolutions.
Now that we know this is interesting, we want to, in a wavelength sense, zoom in and really test what’s going on in this object chemically. What are the kinematics? How is the gas and dust moving? What’s the structure of this object?
But we’d also love to find more of these types of objects. Right now we’re looking at one very impressive special specimen, but that doesn’t necessarily reflect how black holes and galaxies as a population were evolving in the early universe. If we can find more of these objects, then we can start talking with higher statistics about what this population is doing.
And when we start talking about what populations do, that lets us generalize and say “okay, this is how galaxies and their black holes evolve and co-evolve in the early universe.” That lets us then project that forward to say what did these objects turn into in the present day? Or even better, what did our galaxy look like in the early universe?
I wonder if there are folks that you encounter sometimes who say: this is amazing, but how does it affect me? What are you fixing? How can you connect this to something that will benefit humanity?
Do you have an answer to that? Or is simply understanding our universe and grasping how big it is enough of a reason that humanity should care about this?
I think it definitely is enough of a reason, but I always like to go one step further than that. We love to try to answer the question of how did we all get here? Where did this all come from? And I think that pursuit of knowledge alone is really worth all this.
