Chanda Prescod-Weinstein connects history to the stars (Transcript)

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The TED Interview
Chanda Prescod-Weinstein connects history to the stars
July 7, 2022

[00:00:00] Steven Johnson:
Hi everyone. Welcome to the TED interview. I'm Steven Johnson. If you look back over the past few centuries, it's clear we've solved many of the major mysteries in science. I mean, we've sequenced the human genome and split the atom. We can detect radiation that dates back to the Big Bang. But every now and then we get reminded that there are still some big questions out there that remain unanswered.

Take, for instance, the discovery just a few decades old, that the overwhelming majority of the universe is made up of some mysterious substance, a substance we can't perceive directly using any of our existing tools, and which doesn't seem to belong to any of our known categories. A substance physicists now call, somewhat misleadingly, “dark matter”.

It's a profoundly humbling idea. We know so much about our universe and yet still have so much more to discover, or as today's guest described it on the TED stage in Vancouver earlier this year:

[00:01:06] Chanda Prescod-Weinstein:
So we now know that the universe is more queer and fantastical than it looks to the naked eye. That's right.

[00:01:16] Steven Johnson:
That's theoretical physicist and author Dr. Chanda Prescod-Weinstein, who teaches at the University of New Hampshire. As you'll hear on this episode, Dr. Prescod-Weinstein has a great gift for explaining concepts from astrophysics that can sometimes challenge our earthbound hominid brains, or at least mine.

But she has another gift too: a rare ability to connect these vast ideas about what's going on in remote corners of the universe to human-scale experiences back here on our home planet. I think that's one of the reasons why her first book, The Disordered Cosmos, has received such rave reviews and been nominated for so many awards: because it's a book about her pursuit of a genuine scientific mystery that is also grounded in her own life story.

This is a conversation about the nature of the universe, but it's also a conversation about how great mentors can change your life and how we can expose a wider and more inclusive new generation of investigators to the magic of science.


[00:02:36] Steven Johnson:
Dr. Chanda Prescod-Weinstein, thank you so much for joining us on the TED interview. We're really delighted to have you.

[00:02:44] Chanda Prescond-Weinstein:
Thanks for having me.

[00:02:45] Steven Johnson:
We have a lot to discuss. We have the nature of the universe, um, political struggles, your own fascinating history. Um, but in many ways, it's sparked by an extraordinary book that you've written called The Disordered Cosmos.

And I, I think one of the reasons why this book has been so well received, um, is it, it's really doing something that I, I can't think of a lot of precedent for, which is that it's weaving together, you know, profound explanations—and I think really intelligible explanations—about the nature of the universe and space, time, and dark matter, which we're gonna get into, into your own, you know, personal and intellectual journey, um, but also urgent discussions about the, you know, the lived reality today of systemic racism and the history of colonialism and oppression and sexual violence. But I did wanna talk a little bit about, um, those early days and, and how you got pulled into this. Can, can you tell us, you know, recreate some of that early magic in your life and where it came from?

[00:03:49] Chanda Prescod-Weinstein:
Yeah. So if you had asked me this question before the TED conference, I would've given you a different answer actually. And the thing that changed is actually traveling to TED. Um, traveling to Vancouver, was my first time getting on a plane since, um, the pandemic started. So, you know, a little over two years is the longest I've ever gone in my life of not being on a plane. My first plane trip was when I was two months old, right? So I, I spent my life, like, flying back and forth, because my parents were divorced, and I was getting shipped away to family as, as a kid to England, um, over the summers.

So I thought I was gonna be totally miserable getting on a plane again, particularly like wearing a mask and all of that. And then, I was just so excited to be in the sky. So, what does this have to do with me as, as a kid? My very first exposure to anything that we might call physics was learning about pressure above and below the wing of the plane and why the plane stays aloft.

That was my first exposure when I was 10 years old, and I got like really obsessed with it, and I was just like constantly, like, talking about all the physics-y things that we were doing in class. Of course, I didn't know the word physics at that point, like I didn't, or at least I associated that with Einstein, but I had no concept of anything Einstein did being related to that. And I think because of that, my teacher told my mom that I needed more science enrichment.

[00:05:13] Steven Johnson:

[00:05:13] Chanda Prescod-Weinstein:
And so my mom took me to see Errol Morris’s A Brief History of Time, the documentary about Stephen Hawking. And halfway through the documentary, which I had, like I had to miss X-Men cartoons that morning, so I was like really mad we were at a matinee. And halfway through the documentary, Stephen Hawking was talking about solving questions that Einstein hadn't solved in relation to black holes. And I was like, “Wait, that's a job.” And that was like, I was sold. That was it. I was just like, I can spend the rest of my life doing math and get paid for that. And as a working class kid, I knew I needed a job.

[00:05:48] Steven Johnson:
So you're talking about the amazement at exploring black holes being a job you could get paid for. Tell us a little bit about your upbringing. Like where were you raised, um, and the, and the context of that. ‘Cause that's something that's woven through the, the book for sure.

[00:06:03] Chanda Prescod-Weinstein:
Yeah, I mean, I should say for context, so the reason that we were at a matinee was because, like, that was all my mom could afford, right? So I was, I'm, I grew up in East Los Angeles and I'm, we actually had to drive all the way to the west side. And you know, in hindsight thinking about, like, the gas money for that, like would've been a real factor for my mom.

But I think the other thing that happened in that moment, was as, as a Black kid from East LA From, which is pre—which is almost exclusively at that point in time, a central American, Mexican American, and immigrant community—we didn't see people like us doing science, and so it was definitely not through the lens of “Oh, I see someone who seems like me doing a thing” and me realizing like, “Oh, people like me can do that.”

I didn't have that experience with it. I do actually think it's meaningful though that the science teacher that I had at that moment, Mr. Wilson, Frank Wilson, um, who still teaches at the Los Angeles Center for Enriched Studies, which is where I went on to go to high school—

[00:07:05] Steven Johnson:
—hopefully he's listening.

[00:07:06] Chana Prescod-Weinstein:
And yeah, I hope he is. Um, it was meaningful to me that he was Black. I think that that was, he was my, my first science teacher or my first math teacher… I did pre-algebra, algebra, and physical science with him over the next few years, but, you know, my context was really like I had to be able to connect with the ideas, and you know, I got lucky that I had that kind of support where people were saying, “Yes, you can do this.”

And um, I think if I hadn't had that strong connection with math and that strong self-identification thanks to people around me supporting me as like, this is a kid who's good at math, I might not have had that moment of connection. Or I might have been like, “That's a cool job for a white guy to have.”

[00:07:48] Steven Johnson:
It's so important, those early, really, teachers who see something in you. You know, I've, in interviewing people over the years, I can think of it in my own experience as well, that that sense of there's a grown-up in the world who seems to know a lot that you don't yet know who detects something in you and says, “Hey, we need to double down on this.”

So there's, there's something promising there. And then to add to that, as you say, having that person be a Black man in a world where you're not associated with traditionally Black men with science. Um, that's just doubling empowering. And, and I think that's something we, we all should think about a little bit more when we're, when we're dealing with people kind of at early stages of their careers or younger people, it's like explaining that those openings are there for people, I think is, is a really important value to walk around in the world with.

[00:08:40] Chanda Prescod-Weinstein:
Yeah I, I guess maybe it's worth sharing, like, what happened on the back end of that, which is that, like, I had gone into the movie theater, like literally complaining. I have like very small memories of like, “documentaries are stupid.” Like, why are you making me go to see this? And then of course, like I have this moment, like somewhere in the middle where I'm like, “Wait, this is what I wanna do.”

[00:09:00] Steven Johnson:
The o—I just wanna pause just for one second in case listeners have not seen that Errol Morris movie, I mean, shout out to Morris. Can you imagine pitching that as an idea? “So I wanna make a movie about astrophysics and the, the star of it is someone who's completely immobilized and can only speak through a robotic voice.”

Um, you know, that was not, it was not clear that that was gonna be, you know, cinematic gold. But it's a brilliant movie and, and I think inspiring today, even many years later.

[00:09:30] Chanda Prescod-Weinstein:
Yeah, I mean, I definitely think, you know, I have often wondered if part of why I was able to draw that connection was because Stephen Hawking didn't seem like the stereotype of like an able-bodied, het, cis white guy, right?

Um, but he was, he was, different in his own way. Yeah. And so there weren't all of, kind of, the cultural affects necessarily that we associate with someone who might otherwise be embodied like him. And I think that that may have made it easier for me to make that connection and to see myself. And so then I'm coming out of the theater and I'm like, “When can I have the book? Are you buying me the book?”

And my mom is not saying to me, like, “Oh, we can't afford that.” She's saying to me, “Okay, that's great that you're enthusiastic,” and, and genuinely like she meant it, but also, “That’s a book for adults and I'm afraid that you won't enjoy it.”

And so that was, that was like the way that she handled like… And in hindsight, I should ask her about this, but in hindsight, maybe that was her way of being like, “I can't afford that right now, but I'm not, I don't wanna say that.” Um, my uncle, her older brother, my uncle Peter bought it for me for my 11th birthday a few months later, which obviously like my mom had told him to get it for me.

And, and then of course, like it was a book for adults and I was like an 11-year-old with, like, trying to like read about quarks and the standard model. Um, but there was this element that it was, like, a community effort of you know, Mr. Wilson having those conversations with my mom about like what enrichment I needed, and, you know, my uncle chipping in.

Um, you know, part of what I point to in the book is, uh, you know, we can't rely on, sometimes researchers call this happenstance—that we can't really rely on happenstance. Like, that's not a fair system, right?

And so that's part of where my story comes in is, is picking out like the pieces of saying, um, you know, “These were barriers to someone like me and the fact that I got around them or over them doesn't mean that those barriers don't exist for other people or that everybody can just plow through them.”

[00:11:42] Steven Johnson:
Well, and also that community involvement is another theme that runs through the book. Just thinking about how science happens, that it's, it is such a collaborative process. People building on other people's ideas and bringing one piece of an idea to a problem that someone else has contributed another element, and that we… it tends to be always about the eureka moment and the, you know, the great white man scientists, but in fact it's, it is a network, always.

Now I wanna just skip forward a, a couple of years. There's a, there's a wonderful anecdote in the book about another life-changing moment that you have, um, which is a conversation with the legendary astronomer, Vera Ruben, who many people believe should be, you know, Nobel Laureate Vera Ruben. Tell us about that exchange and, and why it mattered so much to you.

[00:12:31] Chanda Prescod-Weinstein:
So I met Vera Ruben. I was introduced to her, and I really wish I could remember who introduced me to her. Um, I was introduced to her at the 2009 Women in Astronomy Conference, which I think was hosted at the University of Maryland. And basically, the first thing that she said to me is she said, “Okay. So how do you think we should solve the dark matter problem?”

And I was like, so, you know, this is almost 20 years later. Not quite 20 years later, but this is, I'm pretty far, I am almost done with my Ph.D. I'm at that point I was working on cosmic acceleration, also known as the dark energy problem. And I didn't have an answer, ‘cause I hadn't thought about the dark matter problem, like, at all.

Partly because nobody had ever asked me what my opinion was. Like I, I never, I never thought it was important for me to have an opinion about it. I didn't think that anybody cared whether I had an opinion about it. And then suddenly I have Vera Ruben, who found the first substantive evidence for the existence of dark matter, asking me my opinion about it.

And so I think that that planted the seed. I will actually say that the other important piece of that experience with her, I had a couple of experiences with her over, over the, the next couple of days. Um, so I got to sit down and have lunch with her and she spotted another, like, older lady and was like, “Nancy, Nancy, come sit with us.”

And I had no idea who this Nancy person was. And she brings Nancy over to the table and sits her down and then looks at all of us young women and says, “You guys know who this is, right?” And we're all sitting there like awkwardly and she says, “This is Nancy Grace Roman. This is the mother of the Hubble Telescope.”

Right? So it was also important because she was giving us a lesson in genealogy, in astronomy, and, and knowing your roots, and knowing your history. And of course, you know, there's the Nancy Grace Roman Telescope is gonna launch later this decade, which I'm, I'm pretty excited about, right? Um, but that, that was one of the lessons that I got from her was not only ask the question and believe that you should have an answer. But also know your history and know, know who the women who walked this space before you are.

[00:14:49] Steven Johnson:
That's a high-powered lunch right there. There's a lot of… I would be very intimidated to sit at that table. I, I will tell you that. Um, what a wonderful story.

Well, that, that takes us to the, the science here. Um, as you said, you know, Vera Ruben was one of the first people to detect evidence of what we call dark matter. Um, and this, this is actually a big part of what your work is focused on. Um, it is a fascinating idea that this idea, that a significant portion, perhaps the overwhelming majority of the universe is made up of this material, dark matter, that we can't directly perceive.

But as I'm sure you know it, it’s a counterintuitive one. It’s hard for the, the non-scientists to really wrap their heads around. So you're such a master explainer of these things, give us a brief, uh, lesson here on both what we think dark matter is, or what the range of debate is, and, and also how do we even know that it's there?

[00:15:52] Chanda Prescod-Weinstein:
Right. So the way that, um, Vera Ruben and Kent Ford first detected the, the first substantive evidence for the existence of dark matter was by looking at how fast stars are orbiting their galactic centers. So stars are orbiting galaxies, and if all of the mass in a galaxy. So all of the matter in the galaxy is just the kind that we can see.

So the kind that radiates light and interacts with light. You would expect the stars to be moving at a certain speed as you get further and further out from the center. And what they saw was that the stars were moving faster than expected. And this is just, like, a very simple, like using frosh physics calculation that the suggests that there's more mass in the galaxy than what we were calculating based on how much light was being radiated.

So there's this mismatch in the two different ways you can measure the mass based on how much light is being radiated, and you can measure the mass by looking at the, the how fast the stars are going. And there's a mismatch between these two mass measurements. So the two possibilities that you have to consider is that your theory of gravity is wrong.

Like you're just interpreting the, the data through the, the wrong theory, or it turns out that there is more mass than we can see. And so that suggests that there is, what we, what we call for historical reasons, dark matter there. And by our current estimates, using not just those calculations and observations, but a whole slew of astrophysical observations at this point, we think that dark matter is about 80% of the normally gravitating matter in the universe.

So it's totally weird. It gravitates just like visible matter does. So what we call visible matter, luminous matter, like the stuff of like everyday life, right? But it doesn't seem to interact through any of the other forces, right? So it interacts through gravity, but we have not so far detected interactions through the weak nuclear force, strong nuclear force, or the electromagnetic interaction.

And so that presents us with this, like, very strange scenario where it turns out that most of the universe is completely invisible to us.

[00:18:15] Steven Johnson:
The, the other issue, I think is the word dark itself. Now, there's some fascinating passages in the book about social and historical consequences of, or context of that word.

But I, I mean it purely in the sense that I think people intuitively think of dark things as things that are, for instance, in a dark room, there’s less light, and so things are dark, or it's a darker shade. Whereas what we're talking about here is matter that does not seem to interact with light in any form.

Um, and I, I wonder whether there was a better way even to, to just describe it that might have made it more immediately, you know, the, just how radical an idea it is might, might have made it clearer to people.

[00:18:58] Chanda Prescod-Weinstein:
So I will tell you that actually the thing that, this was the thing that gave me the most anxiety about my TED Talk, that was like what you're asking me about.

[00:19:06] Steven Johnson:
But good, I, I'm here to make you as anxious as possible. That's, that's my role.

[00:19:11] Chanda Prescod-Weinstein:
Most of our proposed solutions to the dark matter problem involve a new particle, a particle that we've never seen before. And for, for obvious reasons, we haven't seen it ‘cause it doesn't seem to radiate light, right? But we haven't like, detected it in the lab and we're not making things out of it or, or any of the, like, you know, if you're a Star Trek fan, like I am, like none of that.

Um, but there is the possibility. One possibility is that it's made of primordial black holes, and so this comes back to like where I had anxiety. Is that in the scenario where it's a new particle? I’m, you really can't think of it as, like, clear matter or transparent matter where, like, light is just literally going through it, right?

So the example I gave in my talk is if you have a clump of dark matter in your hands, you would feel the weight of it, but your hands would look exactly the same. Like the, the light rays are gonna go through it, bounce off your hand and, and go into your eye. In the scenario where it's a primordial black hole, then actually it is gonna absorb the light.

And so then the, I think primordial black holes are the one dark matter candidate that would actually justify the name dark matter, because it really would be like taking light, um, away and it would actually be absorbing it. Um, so that was kind of like the conundrum I had was I was like, someone's gonna be like, “But if it's black holes, it can't be clear. It can't be transparent.” I'll be honest and say, I don't think it's black holes. I think it's particles. So I'm just gonna stick with that. I'm probably right.

[00:20:39] Steven Johnson:
And if you are holding a primordial black hole in your hand, what, what happens?

[00:20:44] Chanda Prescod-Weinstein:
You're not okay.

[00:20:45] Steven Johnson:
You’re not trying that at home.

[00:20:48] Chanda Prescod-Weinstein:
You’re not holding it in your hands. It's holding you, and you're gone.

[00:20:50] Steven Johnson:
Okay, we'll try to avoid that. Uh, uh, safety, safety tip for kids listening at home.


[00:21:08] Steven Johnson:
You’ve actually referred to yourself as an axion wrangler. Tell us about axions and how they relate to all this.

[00:21:16] Chanda Prescod-Weinstein:
So I have to say, I'm pretty sure that Ryan Mandelbaum, the science journalist, that they're responsible for first calling me an axion wrangler. Um, but I've definitely adopted that moniker.

So the axion is a hypothetical particle. So it's, again, it's a particle that we have never seen, we haven't detected, we haven't worked with it, so we don't know if it's real. And the axion actually first arose as a solution to a completely different problem in particle physics. It happens to be that the axion first came up as an idea in the late 1970s, which was around the time that Vera Ruben and Kent Ford were first, um, you know, publishing their data about what we call rotation curves, about stars moving around their galactic centers.

And essentially, the reason that axions arose as an issue is because in the standard model of particle physics, this is the, the picture that describes all of particle physics, there’s a part of it that we call quantum chromo-dynamics, also known as QCD. And this describes quarks, um, which are, uh, these, some atomic particles like neutrons and protons are made out of quarks, and the general rule for doing the math of the standard model, this is like the secret, the, the secret sauce to doing standard model physics is you keep adding what we call terms to the Lagrangians.

So, um, you know, pieces of the calculation that you're allowed to add as long as it doesn't violate any rules that we know that the universe has to obey. Um, like the speed of light is finite. Like, we know that that's a rule it has to obey. So you can add a term to this equation that there's no argument, no theoretical argument for why the term shouldn't be there.

But when you do, it makes a prediction for something that we haven't seen. So it causes the chart, the neutron, to behave as this, as if it has a charge distribution. You go in the lab and you look for that neutron behavior and that, that’s not there. So there's no, this disconnect between like, why does the theory predict this?

And it works beautifully for everything else, but this one thing, but we're also not seeing it in the lab. So the axion arises as a solution to this problem to basically make that, that term and the, the equation go away. The people, Roberto Peccei and Helen Quinn, the, the two theoretical physicists who came up with this idea, that was the problem they were thinking about solving.

And then not long after, people were like, “Oh, but there's a particle in here and it can totally solve the dark matter problem at the same time.” So Frank Wilczec called it the axion. Steve Weinberg called it the Piglet. As I said in my talk, big missed opportunity. I grew up reading A.A. Milne. I'm a big Winnie the Pooh fan. Why is it not called the Piglet? Like what were you people doing?

[00:24:10] Steven Johnson:
So, um, I mean, a world with piglets and quarks is just a better world, I think.

[00:24:13] Chanda Prescod-Weinstein:
Right? Piglets and quarks. Like we're already, we're already on the literary side. Yeah. Why are we not continuing that trend?

[00:24:19] Steven Johnson:

[00:24:20] Chana Prescod-Weinstein:
Right. And so Frank Wilczec names, um, named it after a laundry detergent.

[00:24:26] Steven Johnson:
As, as one does. I mean, you know.

[00:24:29] Chanda Prescod-Weinstein:
In fairness, this is like a classic example of like somebody who was doing like commercials or whatever, um, or somebody on the marketing team was like, “Yeah, do you know that Greek Orthodox liturgy “Axion”? Why don't we use the Axion esteem for a laundry detergent name?” So that's actually, it is actually a literary name, but kind of like secondhand.

[00:24:50] Steven Johnson:
Right, oh, that’s so funny. I mean, I think that one of the things that's so interesting about this field is that discoveries seem to come from two fundamentally different directions. On the one hand, there are all these stories, I mean, go going back to Einstein and before that, of mathematical equations, formulas that based on their internal logic seem to predict the existence of phenomena that we end up not actually detecting for 80 years or 90 years in some cases, but we think from the math of it, we think there must be this, this thing. So quantum gravity or something like that, right?

On the other side of it, you have so many great stories, like the Vera Ruben story or like, um, uh, cosmic background radiation story where we have these sensors that are out there in the world and they pick up data that initially seems to us to be noise, like our antenna seems to be broken.

This, we can't be hearing this noise from all around at all directions and, and based on that, that input, um, from the external world, we then have to rejigger our equations to make sense of it or, or invent new theories. And I feel like most other fields either work in one domain or the other, but, but this world seems to really get insights from both those kinds of approaches.

[00:26:05] Chanda Prescod-Weinstein:
I think like, you know, the overarching lesson here is that, um, you know, we are not omniscient, so we can't actually predict where these ideas are, are going to come from. And in some sense, the interesting scientific questions that come up, come up through conflict. Um, and I don't mean violent conflict, but I mean conflict of like, you know, “We thought the universe was this way. But then, you know, we turned on our little radio telescope and it's detecting this line that no matter what we do doesn't go away.” Oh, it turns out, so in the case of the cosmic microwave background radiation, which is what I'm talking about, it turns out that that's light that's been traveling through the universe since like about 400,000 years after, you know what we cal—air, big air quotes—the “Big Bang”.

So we can't get rid of that signal because it's literally all around us. It predates us by billions of years, right? So now we have to come up with an explanation. In our scientific models, we now have to account for that mathematically. And then, you know, you do get this flip side where you have a mathematical model that's working beautifully, and then something breaks and you're like, “Wait, what?”

Right? And I think actually cosmic acceleration is a good example of that. Uh, where, you know, we had this working model of expanding space-time. And now we have to explain why that expansion rate is increasing, why it's accelerating, and there's a way to account for that mathematically. But that mathematical explanation doesn't necessarily help you out physically.

Like where did this, where did this thing come from? So I think that those, those questions do arise, and I think it can be really frustrating for people who like to make, um, you know, who like to be in control? And, and, and who like to know where is this going, right? Because like the practice, the actual practice of doing science is not knowing where it’s going, and it is our job as scientists to live at the boundary of what is known and what is unknown and try and push that boundary forward.

But it requires sitting in your ignorance and being okay with it and having some confidence that your tools will allow you to push that boundary outward. So it can be very uncomfortable for people who are like, “Okay, but you know, I wanna be able to predict my bottom line.” That's not what we do in science. Right? That's just not how it works.

[00:28:30] Steven Johnson:
It's such a good point. I mean, I think it's, it, it, it's something in the popular description of science in the way that we use it conversationally for folks who are not, you know, practicing scientists. The word scientific means it's, it's an empirical fact. It's a known entity, it's an uncontested truth.

And in fact, what science is in practice is a series of endless contestations of truth and, and pushing the boundary and coming up with new things that challenge the previous model. And it's not that we live in an entirely relativistic world where there is no truth, but the truth is something you slowly scratch away at over time. And if, if you assume that it's just set in stone and everything is very clear and science has this authority that is absolute, I think you just misunderstand how it works and also the, the excitement of it, I would think.

[00:29:21] Chanda Prescod-Weinstein:
I definitely think that there is kind of this misunderstanding, and part of it is that, you know, the word science just really has, like, multiple definitions. Like sometimes when we're saying science, we mean the community of people who engage in a set of practices. Sometimes we're referring to those set of practices, and it's not one practice, it's actually a set, right?

So I’m… there… physicists do science very differently from archeologists and from biologists, et cetera. And you know, when it comes to the question of like, what is the information that comes out of those practices? If you're doing science well, you're characterizing your level of confidence in that information.

And so it's never an absolute statement of “this is definitively the truth”, but you can say with high levels of confidence that this is probably how things are working. And I think, you know, I get asked this question about global warming a lot, which is like, if there's no such thing as a definitive statement, then like, shouldn't people be skeptical about whether global warming is happening, right?

But I think the point is, is that like, sure, there's like maybe some tiny, tiny, tiny fraction of a possibility that we're like wrong about this. But we're probably not wrong, and whether we're wrong or right, if we make the changes that are necessary for us to make in order to secure our future for the next 7, 10, 20 generations, um, it doesn't matter if global warming is happening or not. The world will be a better place.

And the world will be secured for them, right? So you're always, on some level, there's always that possibility that you're wrong. But as scientists, we get really good at characterizing what are the chances that we are wrong.

And, um, you know, once the community we're, we're consensus oriented, to come back to your comment earlier, we're extraordinarily social in science, often more so than our colleagues in the humanities, kind of ironically.

[00:31:23] Steven Johnson:
Mm. So let's imagine we do get an answer to the dark matter mystery. Um, what are the stakes of, of this kind of question?

[00:31:34] Chanda Prescod-Weinstein:
So I'll start with the least popular answer, which is one version of this answer is, I don't know, right? So, and to situate that in context, Einstein spent 10 years between special relativity and general relativity. He comes up with general relativity. Cool. He's brought gravity into conversation with special relativity.

Now if you've used, like, Google Maps or Apple Maps or something like that in probably the last 24 hours is in, in the case of many of us, um, it used calculations that relied on general relativity, because GPS requires general relativity. Another example is the worldwide web comes out of, um, particle physics, experimentalists, figuring out better ways to communicate with each other.

And so, sometimes the answer is, we don't know what kind of impact it's going to have. But these ideas and these discoveries are often incredibly transformative in ways that, um, can't be predicted apriori. I think the other piece of it is that it allows us to better understand the greater cosmological story.

Every single human community has done cosmological storytelling, and so I think that, you know, per the, the great Black feminist, um, philosopher of science, Sylvia Winter, we are bios and mythoi. We are a storytelling species, that we are bio-cultural. It is in our DNA, I think, probably literally to tell cosmological stories.

When we better understand dark matter, that allows us to better understand how is space-time expanding. What is the future of that? And how does that interact with all of, all of—maybe it does interact with normal matter in some ways that we weren't aware of. And then it can get really interesting in terms of like, what could we do with that technologically?

Um, but I think knowing our universe is part of what we do. And, I sometimes fear that in the rush to think about things that are applied, that we forget that this has value in the same way that writing novels has value. We are storytellers, and my work as a cosmologist, as a particle physicist is storytelling at the end of the day, and I think that that is spiritually nourishing for us as a species.

[00:34:02] Steven Johnson:
I want to come back to, in some ways, where we started, which is that I was talking about how this, this book and your TED talk manages to both talk wonderfully and persuasively about physics and the universe, but also about society today. Um, you, you have a line. Uh, “I used to think physics was just physics separate from people, and I was wrong.” Tell us what you mean by that.

[00:34:26] Chanda Prescod-Weinstein:
When I was younger, I believed physics and engaging in the practice of physics could just be a set of practices and a set of ideas, and that those two things could be separated from who the people were, and in the end, science is a social activity that involves people and you can't take people out of it.

Even if you know someone—I’m sure someone's sitting there going, “But like, what about AI?” But at the end of the day, we make the AI, and there's like a plethora of evidence, right? That, like, we also very quickly teach the AI to be a total jerk, right? Like, that, that happens very, very quickly ‘cause it learns from us.

So I think I had this very naive perspective about it, and I think part of it honestly is that we're propagandized about this, and I use propaganda, like, very intentionally here. There's a beautiful book by Audra Wolfe, who is an independent historian, uh, called Freedom's Laboratory that's basically about the history of science during the Cold War, and I'm literally… the idea that science was, this value-free practice was propaganda that was developed by the US government and was proactively sent out into classrooms as part of the Cold War effort to prove that like, western science and capitalist science was superior to communism and communist science. And it's wild to think, like, my teachers were the children who were first exposed to that, and so they were passing on to me this kind of like propaganda that they were taught.

And so part of what I wanted to do in the book and what I wanted to help people do with themselves, was rethink what we have been told about what science's social relations are.

[00:36:21] Steven Johnson:
Right. So one of the chapters that I found particularly striking, I think maybe because it was more biological, and thus my brain could kind of connect to it a little bit more directly, um, but is a great example of you weaving together the science and the kind of the social history is this kind of extended investigation you do of melanin, the, the molecule that's responsible for skin color. Um, tell us a little bit about that trajectory.

[00:36:47] Chanda Prescod-Weinstein:
Yeah, so I guess like ostensibly, like my thinking about melanin started with going to the doctor and my doctor being like, your vitamin D levels are probably low because the, for people who are Black, they often are. Um, and that this is related to the presence of melanin in your skin. And me being a scientist, being like, “Okay, well clearly I'm gonna, like, read about that.” And you know, even though I'm not supposed to be like this, I'm totally one of those physicists who's like, “Yeah, well everything comes back to physics at some point. Sure, it’s a molecule, it's a biological system, whatever. It's actually a mechanical system.”

[00:37:27] Steven Johnson:
All, all the biologists have just turned off the podcast in anger, but that's okay. Small subset of our audience.

[00:37:33] Chanda Prescod-Weinstein:
I’m sorry, but I’m right. You guys just have to deal with it. So, I, when I started thinking about melanin, I was pulling in all of these things about my physics education, my experience as a physics researcher, and realizing that those things touched on melanin, and that I could actually think about physics in relation to my own physicality.

That physics was actually written on my body in a way that I had, I had not thought about before. And that was a really powerful moment for me. And so I actually, I wrote an essay about this for Bitch Magazine, and then, you know, when I was putting the book together, I was like, “Oh, easy one. I can just like adapt this and this is gonna be the easiest chapter in the book to write.” And it was the hardest chapter in the book to write. And in fact, the, the paperback is coming out, and that was the chapter I revised for the paperback.

[00:38:33] Steven Johnson:
Interesting. I, I mean, I think the, just this idea that there is a whole immense and tragic history of colonialism and slavery, that on some level all orbits around spectral properties of this molecule, um, which gives you some sense of how absurd that history was, that you would make whole decisions about who should enslave whom, and what power dynamic should be between different classes of people based on the way this one molecule reflects or doesn't reflect light.

Um, but bringing it all into one single kind of explanatory history, I think is a, it's just a really unique way of looking at that, that story.

[00:39:18] Chanda Prescod-Weinstein:
Yeah. Honestly, I think the challenge of writing that essay was my initial desire with the first version of it was I wanted to tell fellow black people that melanin is amazing because so many people grow up being told that their melanin makes them ugly. And particularly for the most highly melanated people in the, the black community, the darkest-skinned people, that this is heightened because colorism is a real phenomenon. And so I really just wanted to be like, “Yo, your skin is awesome. It's beautiful. There's this incredible molecule in it.”

People are actually thinking with the molecule about how it can inform our understanding of future technologies. We're literally, like, talking, like, some Wakanda stuff here, right? And that's like, that was part of what I wanted to communicate. And then when I came back to revise it for the book, um, it was 2019, and then it was 2020.

And increasingly, I felt I can't do this without really acknowledging the pain that comes with it and the history that comes with it. It was all a lot to do, and I think it probably deserves more than a chapter.

[00:40:33] Steven Johnson:
Well, I enjoyed it in chapter form, but I will happily read an entire book treatment of it. Um, one of the interesting arguments you've made recently, you made it on the TED stage, is this idea that we should actually rename the newly, uh, launched James Webb Space telescope: “Harriet Tubman”. So walk us through her the way you kind of connect her to the history of space and the stars, um, and why you think that would be an appropriate act.

[00:41:01] Chanda Prescod-Weinstein:
So I believe, and I think there's good evidence for this, that Harriet Tubman used the, the North Star to, to guide people, to freedom and um, to guide herself to freedom.

And I really can't think of a better use for astronomy than liberating people from the extraordinary and harrowing violence of chattel slavery. That is the greatest use of astronomy that there will ever be, which is just freedom work, liberation work. And so I consider Harriet Tubman to be a great American astronomer. She was not formally trained, but frankly, back when she was doing that, um, nobody was really formally trained in the United States as an astronomer. That wasn't, PhDs weren't even really being granted in the United States, um, until around that point, right?

So, I’m, you know, I think people have a tendency to be too limited in thinking about who counts. And so I think that Harriet Tubman just represents the best of humanity. And when we're thinking about going to the stars and going to look at the stars and, and the just wonderful space telescope, as I call it, JWST, is going to see baby galaxies. I'm like super stoked about that and, like, hyped about it.

And, I think that we should be sending the best that humanity has to offer among the stars, and that Harriet Tubman fit that, and that James Webb, the current namesake for the telescope, um, simply did not. Um, I mentioned Audra Wolfe's Freedom’s Laboratory earlier, and part of the story that she tells in the book was the role that James Webb played in the development of psychological warfare as a technique.

Um, and so I object to him being attached to the telescope for that reason, but I also object because he played, um, what I believe to be a key role in the evolution of the Lavender Scare, which was basically the hunt for, um, LGBT people in federal government work. And we know that it, in at least one case under his leadership at NASA, that a gay employee was arrested for being gay and then was extra-judicially interrogated by the head of security at NASA and subsequently fired.

And at that point in time, the culture at NASA was that a decision like that would've come from the administrator's office. Um, that's not the best of humanity. Like, we can just do better, and, and Harriet Tubman… Harriet Tubman represents that. So for me, as a black queer person who works on NASA projects and, and who was a NASA fellow, that's what I want.

[00:43:41] Steven Johnson:
The, the question we ask all of our guests on this show, which I think you probably may have the most profound answer to this, given the scale of, of your work, um, what in your field is the great unsolved problem that really drives you? What's the, what's the thing kind of that you would love to fast forward 10 years and, and find out what the scientific consensus has become? What's, what's the mystery that you're, that you're most intrigued by?

[00:44:12] Chanda Prescod-Weinstein:
I have two answers to this question, and I'm gonna break your question a little bit.

[00:44:16] Steven Johnson:
Great. Fabulous.

[00:44:17] Chanda Prescod-Weinstein:
So, um, obviously the question that seem—that drives me right now is dark matter. I really, I wanna know what dark matter is. I wanna know where it is.

To what extent does it maybe have some interactions with standard model forces like electromagnetism? I, I, I realize I didn't say this earlier, but PJE Peebles, the, the Nobel Laureate Cosmologist, he refers to it in his recent book from Princeton University Press, um, A Subluminal Matter. So, you know, maybe it does radiate light, but not at the, the level that we can see it.

So I would like to know: does it radiate light? How much? What frequencies? That, that kind of thing. So that's the question that drives. But I don't wanna fast forward because if I fast forward, then I actually miss the experience of like doing the math and working with my students. And I think that you can be pretty miserable as a scientist if you go into science only wanting to get to the answers and not enjoying the process of getting there because most of your life is the process of getting there and sometimes not getting there. And so you have to really enjoy the process of trying and, and working things out. Um, I will say the question that I just really wanna know the answer to, and I've decided that for the moment I'm not working on, and so I would be okay with fast forwarding is I wanna know the answer to the cosmic acceleration problem.

So I wanna know what causes cosmic acceleration. If it is something like the cosmological constant, I really need a better scientific explanation for that than the anthropic principle, which says that it has the value that it does, because if it didn't, we wouldn't exist. Like it's, I find that to be a deeply unsatisfactory answer, and I just want another one.

[00:46:04] Steven Johnson:
All right, well, we'll, uh, we'll have you back in 10 years and hopefully there will be, uh, an, an answer to at least some of those questions. This has been a fascinating conversation and I just keep coming back to a, a line that really moved me in, in the book, um, which is maybe a good place to end, which is that you have this vision of, of wanting all children, all children to have access to the night sky.

Um, it's, it, it, it does seem like your work is doing a wonderful job of, of advancing and fighting for that future. So thank you for fighting that fight and being such a great, um, and good-natured explainer of all these complicated issues. We really appreciate having you on the show.

[00:46:42] Chanda Prescod-Weinstein:
Thank you so much for having me.

[00:46:47] Steven Johnson:
That's it for the show today. The TED Interview is part of the TED Audio Collective. This episode was produced by Wilson Sayre, who's also our managing producer. The show is brought to you by TED and Transmitter Media. Sammy Case is our story editor, Fact-checking by Nicole Bode. Farrah Desgranges is our project manager, and Gretta Cohn is our executive producer.

Special thanks to Michelle Quint, Anna Phelan, and Allie Graham. I'm your host, Steven Johnson. For more info on my other projects, you can follow me on Twitter at @stevenbjohnson, or you can sign up for my Substack newsletter: Adjacent Possible.