Interview with Dr. Chiara Mingarelli, Yale Astrophysicist Who Studies Black Holes and Spacetime
Dr. Mingarelli's childhood dream was to study black holes—and she's achieved it! We're excited to share our interview with her, coming on the heels of some exciting news about her work.
Click on the YouTube video above to watch the full interview.
We are so excited to share our third interview with astrophysics professor, Dr. Chiara Mingarelli. If that name sounds familiar, it may be because Dr. Mingarelli has been featured in the news lately for her contributions to the NanoGrav collaboration that is changing how we think about gravitational waves, spacetime, and black holes. News about NanoGrav’s most recently released results has been featured in the Wall Street Journal, Washington Post, and more.
As a reminder, here at Origins, we explore the unique origins stories from the childhoods of leaders in science, technology, engineering, arts, and mathematics (also known as STEAM). We’re honored to be welcoming Dr. Mingarelli today.
Dr. Mingarelli is a gravitational wave astrophysicist at the University of Connecticut Department of Physics and an Associate Research Scientist at the Flatiron Institute’s Center for Computational Astrophysics. She was a Marie Curie International Outgoing Fellow at the California Institute of Technology and at the Max Planck Institute for Radio Astronomy.
This year, she was appointed to the Executive Committee of NASA’s Physics of the Cosmos Program Analysis Group and also became the 2023 HEAD Early Career Prize winner for her outstanding contributions to the field of gravitational waves. Other notable honors include being a runner-up for the 2022 Springer-Nature “Inspiring Women in Science” award, being the American Physical Society’s “Woman Physicist of the Month,” and receiving grants from the National Science Foundation, the European Research Council, and Amazon.
Dr. Mingarelli also is a writer, speaker, and creator who has conducted science outreach in a myriad of ways. She has written articles for Scientific American, CNN, The Wall Street Journal, Popular Mechanics, the BBC, and more. She has also been featured on podcasts such as Sean Carroll’s Mindscape and regularly contributed to a blog/YouTube channel called Smart Girls, whose motto was “Change the world by being yourself.”
In the fall of 2023, Dr. Mingarelli will be joining the Department of Physics at Yale University. We welcome Dr. Mingarelli to Origins and invite her to share with us the touchpoints of her childhood and early career that have led her to where she is today.
Please note this interview has been edited and condensed.
Dr. Natasha Wilson (NW): Welcome, Dr. Mingarelli, to Origins. We're happy to have you here. Here on Origins, we like to focus a little bit on childhood, and especially those touch points that brought you to where you are today. And so if you wouldn't mind, tell us a bit about your childhood.
Dr. Chiara Mingarelli (CM): Yes, it's so nice to be here. Thank you so much for the invitation, Dr. Wilson. I grew up in Ottawa, Canada, in a small suburb called Rockland. I was outside a lot. I loved to play outside, and I loved looking at the night sky. My friends and I would take walks around our block, sometimes for hours and hours at a time. And we would look up at the night sky and just wonder about the stars and what was out there and think about exploring. And that was really my thing when I was a kid. I just loved to explore and discover things.
I thought that in the best version of my life, I would be able to explore and discover new things about outer space. When I heard from my dad that black holes were a thing, and he described them to me—he's a mathematician—I was hooked. I just couldn't believe that such seemingly magical objects existed in nature and that one could have a career studying them. I think I was 10 years old when I asked my dad, “I really like astronomy, but is there astronomy with more math in it, like astrophysics?”
He was like, oh my God, yes, there's astrophysics, and you can do it. I was like, great, okay. And then a bit later on, I was like, well, I think I should tell you that I know that you've been lying to me.
And he was like, what? And I said, well, you said that I could have a career studying black holes . . . if that were real, then everyone would be doing it. So obviously you think I'm a little kid. Don't lie to me anymore. Tell me the truth.
Today reflecting back on that, it's funny, but it's also sort of true, right? It's not necessarily true that everyone can have that vision when they were a kid and grow up to be an astrophysicist. I had a lot of privileges growing up with a father who was a professor and could guide me and tell me that was a possibility. I think it's so important to be able to picture your future, to have some sort of concrete image of yourself and to . . .be able to see role models.
That's another important thing that I had. When I was in high school, I was introduced to a professor, Victoria Kaspi at McGill University, when she was just starting out there. And she was an amazing role model for me. She's one of the pioneers in pulsar timing and has done really important work in the field. And I met her when I was 17 years old, so I could picture myself being a professor and doing what she did . . . I was really lucky, I think, to have both parents who are really invested in showing me role models and supporting my interests.
NW: That's great. So did your love for mathematics bloom because of your relationship with your father and his profession in mathematics?
CW: You know, it's hard to say. I think so. There's not another version of the universe where I can compare what would happen if we didn't. But I think it was always a part of it. My father loves math so much that I always found it to be very infectious. But at the same time, I have six siblings. I'm number two of seven children. And my youngest sister is also a scientist—she's studying biology. I was the only one that really got hooked into math. And so whatever that spark was that my dad had that he saw in math, I also have it. But for me, it just manifests in a slightly different way. I project that onto space and black holes in my childhood and the night sky full of stars.
NW: That's amazing. I used to love looking out at the stars, and when I was a kid, one of my favorite things to do in the world was to go to the planetarium.
CM: Yes! I also remember a really influential part of my childhood was discovering the speed of light and that the light leaving the stars, arriving now, left potentially thousands of years ago, maybe even longer. There's like time travel that's inherently happening from the time that photon left the star and traveled tens of thousands of years and hit my eye so that I could see it. That's bonkers. That totally, totally blew my mind. It still does. . .
NW: It is incredible. The size, the magnitude of space.
CM: Yes.
NW: You spoke a bit about who you looked up to when you were young. What was school like for you, especially having a fascination with black holes? The classes you ended up enjoying, and how you interacted with your peers.
CM: I feel from the way that you're asking the questions that you know the answers!
NW: Well, you never know. You might have gone to a school full of black hole lovers!
CM: (laughs) No, I went to Rockland District High School. It was a public high school, and there were no black hole lovers. There were no black hole haters. So that's good. But yeah, school was always challenging for me in a lot of social ways. I really prided myself on being very good at school. I thought that everyone should also be very happy that I was doing so well at school, but my classmates thought that just made me a super nerd. And so it was socially difficult for me when I was a kid. There's a few times that I didn't go out at recess and I stayed in and I read the dictionary. But I loved reading the dictionary. I thought it was fun. And I also had Encyclopedia Britannica back in the day. And I would also go through that, because it was like Wikipedia printed, right?
NW: Yes.
CM: So it was hard. It was hard to express that I had decided I wanted to be an astrophysicist and now it was my driving force. It took me through elementary school, high school, university, and I guess I never left university. I'm still there.
NW: What made you overcome those challenges? Was it just the love of what you were doing, the love of learning, or were there other ways in which you overcame those challenges of social difficulties and social interactions?
CM: Yeah. I found two or three people that I really got along with. I hung out with them sometimes, but not all the time. . . . And when I got to university for my undergraduate degree, it was less awkward because I felt like the people that were now my classmates were more people like me. It was a lot easier to talk to them, because I felt like they understood me a bit more, and they were more like me neurologically perhaps. So that got a bit easier, but I still had different groups of friends, and I didn't have one particular niche where I fit in.
I did a double major in math and physics when I was an undergrad because I went to the university where my dad taught. He told us all very young, “I have seven children and I can't afford to pay for university for all of you. You get free tuition at my university. You can go there, or you can pay for yourself to go somewhere else.” So I was like, I will go to Carleton where you teach.
I did the double major in math and physics because there was no astrophysics program, and I wanted to be an astrophysicist. . . It was extremely challenging, but so rewarding. It was also really challenging to be working up to three jobs at the same time, because I moved out of my parents' house and I was living with my younger sister. We had bills to pay and didn't qualify for student loans, so I was working a lot. That was really, really hard. But it was really my love of astrophysics that kept me going.
And there were multiple times—one in particular stands out—where the human resources person comes by and says like, hey, you're really good at this call center job. Like, why don't you just quit your degree and start working here full time? You're gonna end up here anyway.
NW: Oh, wow.
CM: I was like, no, I'm gonna be an astrophysicist. And he was like, yeah, sure.
NW: Wow!
CM: Exactly.
NW: That's rude.
CM: Yeah. That might be true for a lot of people that are doing different kinds of degrees. I don't know. But [I thought], you obviously don’t know who I am. I'm going to be an astrophysicist and you don't know it, but I know it.
And there were a few times where people were like, why are you doing this? Just get a job. And I was like, no, I'm going to do black holes.
NW: Was it maybe because of the community that you were in, where there wasn't a lot of higher education? Or was it because of people's thoughts about women in science?
CM: Oh, it's hard to say. Ottawa is the capital of Canada and a big government town, so a lot of people get undergraduate degrees and then go and work for the government. So it's hard to fault people for seeing that path for me. That's really the path that a lot of people take. I just figured, oh, you think I'm someone else. Like, that's not me.
And I don't know where that very strong sense of who I am [came from], the fact that I identified myself as an astrophysicist at 10 years old. It never occurred to me that it didn't happen in other people. . .
When I got to graduate school, I was almost thrown off track again, but then it course-corrected. I did a year of experimental work when I first got into my PhD program on this experiment that was looking for deviations from Newton's inverse square law—so testing gravity on very small scales. And deviations from this could come from things like String Theory. At first I thought, this is super cool. I'm testing String Theory. This is awesome. But I really didn't get along with my supervisor. And after a year of butting heads, we parted ways in a spectacular, huge argument with the department chair. The group that ended up saying, hey, you know what, you have really good theory skills, come and work with us, was the gravitational waves group.
So I went back to black holes, and it was a very natural fit. It worked out really well.
NW: It sounds very interesting that you were drawn to black holes all through your years that you were growing up, but then it was almost kind of like now the black holes are drawing you in, because you went off in a different path and then you ended up right back where you belonged.
CM: Yeah.
NW: That's really great. Now that we're broaching the subject of black holes, could you tell us a bit about black holes themselves?
CM: Yes. There's different kinds of black holes.
Let's start off with the small ones. We call them stellar mass black holes because they're a few times the mass of the sun. Those form in supernova explosions. You have very large stars that are something like 30 times the mass of the sun. And those can undergo supernova explosions at the end of their lives.
As a sidebar, our sun is never going to undergo a supernova. It's not big enough.
But more massive stars can undergo a supernova. And when they do, they have this huge implosion event. The implosion crushes the matter and the core of the star. It fuses protons and electrons into neutrons, and then it fuses the neutrons together. The end product is something that we don't have physics to describe. We call it a singularity because mathematically that's what it is, but we have no idea what it looks like, if it really is this tiny little point or if it's this blob of quark-gluon plasma or whatever it is. We have no idea what that material at the center of a black hole is. So this stellar core remnant that we call a black hole, it's not a hole at all. It's something in the middle. And the escape velocity of this is so large that light can't escape. . .
Source: https://commons.wikimedia.org/wiki/File:Black_hole%27s_accretion_disk.jpg
Supermassive black holes, which is what I work on, have a completely different formation channel. . . One of those black holes would be the size of our entire solar system, which is bonkers large.
So those supermassive black holes, we're not really sure exactly how they're created. One of the ideas is that there was this large gas cloud in the early universe that just directly collapsed into a supermassive black hole that was maybe 100,000, 10,000 solar masses, something like that. And then those ones found each other. . . they started big and now they're even bigger, but they don't come from the stellar mass black holes, which is kind of cool.
NW: Fascinating.
CM: So back to your other question, what do I work on? I study supermassive black hole mergers. We call them supermassive black hole seeds, the first supermassive black holes, however they got there—we're not really sure. Hopefully one day we'll figure it out. Maybe someone listening to this will figure it out, because they also love black holes. That would be awesome. They find galaxies, the early galaxies, and then they co-evolve together, like how early cells got nuclei, and they kind of co-evolved together. The same thing happened with galaxies and black holes. They seeded galaxies with black holes. And then the galaxies started merging, and the supermassive black holes started merging.
Source: https://en.wikipedia.org/wiki/Binary_black_hole
And when supermassive black holes merge, they create gravitational waves, which are ripples in the fabric of space-time itself. These space-time ripples affect the distances between objects. So if you and I were sitting across the room from each other and a gravitational wave came down from the ceiling and into the floor, we would get closer together and then further away. Then we would be expanded and look super thick and then contracted. And we would have this crazy oscillation pattern go between us. But we wouldn't be moving. It's actually the fabric of space-time itself that's moving between us.
This is what I look for and this is what I model. I look for these gravitational wave signatures as they pass and I also create models of what they should look like. It's a lot of math and a lot of computers and a lot of fun.
NW: It sounds fun. So when you are looking at these gravitational waves, are you essentially studying what happens to the stars that are nearby these supermassive black holes?
CM: We study the effect of pulsars, which are neutron stars. They're big balls of neutrons that are about one and a half times the mass of the sun, and they spin around a hundred times a second. If you took the sun and squished it to the size of Manhattan and put it in a blender, that's what one of these pulsars are.
They spin around a hundred times a second and send us regular flashes of radio waves. Those flashes are so regular that we can measure exactly when they should arrive. We measure when they do arrive. And the difference between those two things could signal the fact that a gravitational wave is transiting our galaxy, because it means that the pulsars got closer to us and then further away, and then closer, and then further away.
So this is a way of using nature itself as this gravitational wave detector because these pulsar pulses are so accurate, any deviation from when those pulses arrive could signal the presence of space-time itself being deformed.
NW: Interesting. So I know that there's a supermassive black hole at the center of our galaxy, the Milky Way. And my understanding is that there are supermassive black holes in the middle of other galaxies. Is this a typical feature of galaxies?
CM: Absolutely, yes. Most massive galaxies have supermassive black holes at the center. And I say most because we haven't looked at all of them, so we don't know for sure. But when we've looked, we've found them. In fact, the Event Horizon Telescope collaboration in the last few years has actually taken pictures of our own supermassive black hole, Sagittarius A star, and a neighboring one, M87, that they call M87 star.
NW: And so these supermassive black holes at the center of the galaxy, is it believed or known that they form in a similar way to other supermassive black holes in the universe?
CM: That's right. So our supermassive black holes were seeds at one point as well and were smaller. And one of the really interesting things about these gravitational wave experiments now, like Nanograv, which is the project that I work on, is that we can find these individual merging supermassive black hole signals. And that can tell us what the masses of the black holes were, from which we can infer what the host properties of the galaxies were. Then we can kind of work our way back in time as an additional check to see, does everything work the way that we think it should work?
Source: https://commons.wikimedia.org/wiki/File:The_History_of_the_Universe.jpg
So if I start at the beginning of the universe and then say, I have a small black hole and a small black hole—and by small, I mean maybe it's only a hundred thousand solar masses, right? Small, a baby supermassive black hole—and these galaxies merge, then I get this gravitational wave signal. . . Then I build up mass, and then what's the end product? That's really what we're looking at when we look nearby. We're looking at the end product of this cosmic merger history of all of these events.
So it's a nice check on, how does the universe work? Does it work the way that we think it does?
. . . Or not. What if they're not there? What if the signals aren't there? Then we'll have to rethink a whole bunch of stuff about the early universe. That would also be very cool. But that's why we build these detectors, right? Because we have to go out and see it. It's not enough to just come up with fun theories, which I love to do. But I think one of the signatures of my theories is that they're all very testable.
NW: Right.
CM: Because if they're not, then I'm not really sure what the point is.
NW: Yes, of course. So I'm curious about the relationship between a supermassive black hole and the galaxy that surrounds it.
CM: Yeah, so the supermassive black holes that are local to us are the product of those seeds merging with other seeds and then over the whole history of the universe becoming very big. That's the end product. How galaxies and their black holes co-evolve is an open field of study. It's something that everyone is very interested in right now in astronomy.
NW: Oh, okay. Yeah. So this one is just kind of a curiosity question because I'm a little bit of a nerd about these things, but I'm also not an expert.
CM: Excellent.
NW: So this is about wormholes, which is somewhat related to black holes, but not exactly, which were predicted by Einstein and Rosen, Einstein-Rosen Bridges. Do you think that they can exist? And if so, how could they be detected?
CM: What a great question. So Einstein-Rosen Bridges: The theoretical calculations I believed allowed for one electron to pass through it. Not people or spaceships. And one of my colleagues, Kip Thorne, has thought a lot about wormholes and over the last few years has become much more pessimistic about if they're real. One of the reasons for his pessimism, because he used to be a big proponent, is the fact that to keep a wormhole open, you need a lot of negative energy, which probably comes from negative mass. And how can you do that?
So this is either, we got too imaginative and created something that maybe can't work, but my gut feeling is that we need a fresh set of eyes and fresh brains and people who are really excited about wormholes to figure it out. Because it seems to me like it's something that should be able to work. Space-time is long and meandering and there's these hills and valleys. And why can't we make a tunnel through a hill? We do it all the time here.
NW: Good point.
CM: We know that we need some sort of exotic material that has negative energy, but if you were to have told people 200 years ago that gravity is the result of curvature of space-time, they would have laughed you out of the room. They're like, what does that even mean? . . .
I want to believe that it's true. Doesn't mean that it is, but I want to believe it.
NW: I do too. I think it would be really awesome. And it would just be awesome to discover whatever it is that would actually keep it open.
So I do have a question from our previous guest, Dr. Carlotta Berry. And so she asks, What problems in your current work keep you up at night?
CM: I guess I have two answers. I have a scientific answer and a reality answer.
The scientific answer is, what am I missing? Have I left out something? Did I dot my I’s and cross all my T's? In terms of my work, the bouts of creativity just kind of happen and I can't control it. I've basically stopped worrying about it because it happens when it happens, but I can't force it.
The reality of what keeps me up at night is, how am I going to pay for all of this? I need to get grants and I need to write big grants and I need to spend a month, six weeks of my life putting together this massive document of all of my research plans for five years and then submit it to the ether.
Then some board gets together and decides if my work is worthy or not. And then I get money or I don't get money.
And then if I don't get money, how do I pay my students? And I care so much about my students. I want them to all be okay. I don't want them to have to look and find their own sources of funding. It was so difficult for me as a student to have to work so much that I really would like for them to be able to focus on their research and not worry about things like that.
NW: Yes, that's also a good thing to share for those who may be thinking about the path of academia. That is a big challenge in academia and it can be a very time-consuming and very difficult process. And sometimes you're just like, why can't I just do my work? Why can’t I just do my research?
CM: Right, exactly.
NW: So it's good to share the realities of it and that it still is something that you're passionate about regardless. So I hope that all of your grant work goes really, really well and you can get lots of money.
CM: Thank you. My students will be really happy if I can make it rain.
NW: So to begin to wrap up, I have a few random questions to ask you.
This question is inspired by the podcast “The Diary of a CEO,” and I always hope that he will be okay that I use this question. It’s what gave us Dr. Berry’s question for you. But what question would you like us to ask the next person that we interview?
CM: What inspires you?
NW: What inspires you? Very good.
CM: Mhmm. I think it's always really interesting, right? Like what inspires different people, and then how they choose to answer the question is also really interesting because it's kind of open ended.
NW: Yeah, definitely.
CM: What inspires you?
NW: Oh, what inspires me?
CM: Yeah.
NW: I am inspired by a lot of different things. I'm a very curious person. So I guess I'm also inspired by other curious people. Like people who, like yourself, just find something so interesting and commit yourself to understanding it and learning more about it and sharing that knowledge with others. That’s really inspiring to me.
CM: Oh, fantastic. Thank you.
NW: So would you like to tell our audience where they can find you and learn more about you and your work?
CM: Yes, I have a website which is chiaramingarelli.com. You can visit that to see what I'm up to. And I'd also like everyone to check out the nanograv.org website on Thursday, June 29th. [Editor’s Note: You can read about the announcement now here!] We will have released a suite of papers that talk about evidence for a gravitational wave background, which comes from the cosmic merger history of supermassive black holes. So definitely check that out.
NW: Very exciting. We'll definitely make sure that it's linked and everybody knows about this excellent announcement and the great work that you're doing. So thank you so much for making time to speak with me today. It's really fascinating to hear your story from just staring out at the night sky and how that inspired you to then move towards astrophysics—just those little moments in our childhood that seemed so mundane, but can just direct the whole course of your life. And thank you for kind of going with my geekiness on wormholes a bit.
CM: Oh my gosh, the wormholes is my favorite part. I love your questions about wormholes. Thank you so much. This is so much fun.
NW: Yes, this was so much fun. And I hope that you have a great day and thank you for joining.
CM: You too. Thank you so much.
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