Research Spotlight: Tristan Smith and Gravitational Waves

Editor’s note: This article was initially published in The Daily Gazette, Swarthmore’s online, daily newspaper founded in Fall 1996. As of Fall 2018, the DG has merged with The Phoenix. See the about page to read more about the DG.

This is the first interview in the series Research Spotlight, in which I share conversations that I have with faculty regarding their research, their journey within their field, and their field in a broader context.

Tristan Smith is a an Assistant Professor in the Department of Physics and Astronomy, and, besides gravitational waves, his research interests include early universe cosmology, tests of modified theories of gravity, and analysis of the cosmic microwave background.

09/21/2017

AIDAN REDDY: Could you tell me about the paper that you co-authored last year regarding the first detection of a gravitational wave?

TRISTAN SMITH: What happened in 2015 was the beginning of a completely new field in astrophysics. I went to grad school at Caltech, which is one of the two centers for the instrument called LIGO (Laser Interferometer Gravitational-Wave Observatory) that observed these gravitational waves, so I knew a lot of the people who were part of it. My own research intersects with it because one of the really interesting properties of gravitational waves is that they interact with next to nothing. Gravity is a very weak force. You might think, “Well, I’m being held to the earth by it… that seems pretty strong.” But if you pick up this mug in front of us, the muscles in your arm are able to produce a force stronger than the gravitational force due to the entire earth pulling down on it! That makes gravitational waves really interesting, because unlike light, which, if hits an opaque object, doesn’t pass through, gravitational waves travel through almost anything without being disturbed. This means that there are gravitational waves that we think exist that come from the earliest moments of the universe, but because they’re so weakly interacting, they come to us nearly undisturbed. So, if we can detect those gravitational waves, we can obtain information from a fraction of a fraction of a fraction of a second after the big bang, but because they are so weakly interacting, they’re very hard to detect. We haven’t seen those waves yet, and much of my research focuses on understanding what information we would learn if or when we do detect those gravitational waves. I had a lot of interaction with people at Caltech who were working on LIGO around those questions. There’s research being done here at Swarthmore in that direction.

REDDY: What about the research projects you are working on now?

SMITH: I have a few projects going on related to gravitational waves. One of them that I’m very excited about right now is with a collaborator named Robert Caldwell, who’s at Dartmouth College. We’ve detected gravitational waves on the Earth, and that’s made people way more excited about gravitational wave detection. There’s been plans in the works to take the kind of instrument that has detected gravitational waves on earth, LIGO, and put it into space — making a space-based gravitational wave detector. Robert and I are both thinking about new designs for that space-based gravitational wave detector that would give it functionality beyond what the current design gives it. That’s very, very exciting stuff. It’s very creative. We’re thinking of things we may want to detect with the instrument, and then thinking: “Well how do we need to modify the current design in order to build in sensitivity to those interesting things?” I’ll give you a little detail as to what the “interesting this” is. You might’ve heard that light, the electromagnetic waves in this room, has a polarization. We have polarized sunglasses, for instance. Gravitational waves also get polarized. One of the things that Robert and I are interested in putting in the new design for the space-based gravitational wave detector is enhanced sensitivity to the polarization of gravitational waves. It’s not something that anybody has stopped to really think, “How do we better design this instrument to detect the polarization of gravitational waves?” That’s what we’re sitting down and doing, and I’m really excited about that.

REDDY: How can I visualize what’s actually going on when light is polarized? Gravitational waves?

SMITH: The light that’s flying through this room right now is made up of an electric field, essentially. The electric field is a vector, so it has a direction. The light passing through this room has an electric field that’s oscillating up and down and also left and right. So, the light in this room, for the most part, is not very polarized when it’s coming from a light bulb. But, if the light reflects off of a table, then the up-down part of the electric wave has a harder time bouncing off of the table than the left-right one. So, the light reflected off of a surface like this table is partially polarized. That’s what your sunglasses are made to cut down on. They cut down on the glare, which is light reflecting off of surfaces, like this table or the ocean. You’ll see a better contrast between different objects when you’re wearing polarized sunglasses. Gravitational waves have a similar property. Unlike electromagnetic waves, which are made of vectors, arrows that we can imagine, gravitational waves are, at the most basic level, described by something called a “tensor”, which is a very scary word to a lot of people. There are animations that show the effects that a gravitational wave would have on a ring of particles if it were to pass by. In one polarization, the ring would stretch up and then go out on the sides, and then stretch up again, like a “+”. If a gravitational wave were polarized in the opposite way, the ring would stretch out on a diagonal, come back, and then stretch out on the opposite diagonal, kind of like an “x”. We call these “plus” and “cross” polarizations. There’s a lot of information about the physics of what produced the gravitational wave if you can detect its polarization accurately.

Video representation of gravitational wave traveling through ring of particles:

REDDY: I read a little bit on Swarthmore’s website about an interdisciplinary physics workshop you did a few years ago. Do you have any plans to follow this up?

SMITH: It’s something that I’ve been doing every year that I’ve taught Physics 5. We’re going to be doing it this year too. It’s an element of what I’ve done here at Swarthmore that I’m really proud of, because I don’t think anyone would disagree that we are in a time where effectively communicating scientific ideas and rational thought is clearly important. One of the things that we do in the classroom is teach the concepts of physics, and everybody is asked to do problems and talk to one another. There’s a lot of communication there, but I feel like, in the scheme of things, there’s not as much attention paid to stepping outside of that for a moment and thinking about building skills around effectively communicating those ideas to other people in our communities — our friends, our family. The science communication workshop is exactly about that.

What I’m really excited about is that it’s a partnership between myself, the Center for Innovation and Leadership, which is headed by Katie Clark, and Elizabeth Stevens, who’s a theater professor. We actually do acting improv as part of this workshop. Some people might think that acting is all about entertainment. What it’s really about, if you’re an actor, is communication — both between yourself and the other people that you might be playing with, but also to the audience, and when you get into that improv mindset, you are much more attune to connecting to other people. I think I can say this from my experience: scientists generally have a harder time connecting to non-scientists around the topics of their research. If they had some more experience with improvisation, I think that there would be a natural building of that skill to be able to really communicate those ideas. It’s not “dumbing it down”; it’s about passionately communicating the things that we find fascinating in science to people who haven’t been exposed to them.

REDDY: Given the current political climate, and environmental climate, what is the importance of science literacy?

SMITH: Throughout my time in science, I’ve been fascinated by people who would be considered by the scientific community to be quacks.

REDDY: Quacks?

SMITH: People who write articles and send them to people like myself, and colleagues here at Swarthmore. It happened when I was in graduate school to my Ph.D. advisor and other people on the faculty. These articles would present absurd results, but the person who wrote them believed in them deeply. They’d make claims like “Einstein was wrong,” and they’d have the “proof” that all of the consequences of special relativity are completely misguided. They’re the ones who know it and they want to have a scientist agree with them. I remember in grad school once, a friend of mine was talking to somebody who claimed that Einstein was wrong, and he said, “Well I’m not really an expert in Einstein’s theories, but my friend and colleague Tristan Smith is.” He sent him to my office, and I spent three hours talking to him, trying to explain why what he was saying to me didn’t make sense to me. There are a lot of different reactions to those types of attempts of non-scientists to come in and say “Everything you’re doing is wrong. I have a completely new theory of “x”. I view it, I think, slightly differently.

I’m very impressed by people who do that, in a way, because I feel like many of them, at least the ones I’ve spoken to in some detail, are passionately in love with science, but they haven’t gotten that scientific literacy, and they want to feel actively connected to it. The way they’ve found to do it is kind of imbalanced. They have an inflated view of themselves, for sure. But there’s something important in that act. There was a time in physics where everyone could understand everything in physics if they put their mind to it. We no longer live in that age. We live in the age of specialization. My specialty is theoretical cosmology. I have some literacy on other topics in physics, but when you start to go farther afield, I have less and less knowledge, which is natural. But, I think what has been lost, related to this transition from a world in which everybody who applied themselves to it could understand what the eminent scientists of their day were talking about, to a world in which you can read an article written in the New York Times, but that’s about it, is that people have lost touch with the idea that what science is, and that what scientists are doing, is deeply human.

Through losing touch with that, I think in part, people have lost faith. Well, faith is maybe a bad word. They don’t believe that science works because they don’t understand it. That’s natural. So I think science literacy, if it were to bring people into the conversation, and give voice to the non-expert, the person who might be interested but doesn’t have the mathematical background to really get into a certain subject, that, I think, could be very powerful. That’s also very deep and systemic and difficult to address, but I view that some of the stuff that we’re doing here, in thinking deeply about effective science communication, is trying to get at that disconnect between the larger society and what happens in a place like Swarthmore, in terms of research. It’s getting at this feeling that scientists are a separate group, that they think their own things, and if I don’t understand it myself, then maybe it’s not true. I don’t know how we’re going to get to a point, or whether we were, at some point, where people feel connected to science and the people who are doing it, even though they might not have the tools to understand it deeply. If there were scientists who were really excited and willing and engaged in talking to others about what they do, I think that’s a step in the right direction.

REDDY: I can really relate to that idea. A big part of the reason why I’m seriously considering studying science here is things like Neil DeGrasse Tyson’s TV series, Cosmos, and Brian Greene’s book, The Elegant Universe.

SMITH: Those people have really taken the time and energy to communicate those things. What’s interesting to me — maybe it’s less true about Brian Greene — is that Neil DeGrasse Tyson is not an active researcher that I know of. His job is to communicate science. I think we’re going to be hopefully in a different place with that communication when it’s expected and understood that to be a scientist means to also be a communicator, and it’s not left to some particular individuals who have to leave the research world to do the communication. I think some people view it as, “Well yeah, that’s great that Neil DeGrasse Tyson is talking about all these things. I can then just focus on my little world and everything will be okay.” Well, no, I want everybody (there’s only one Neil DeGrasse Tyson, he’s amazing) to feel a responsibility to really actively engage in stuff like what he does.

REDDY: When and how did you know that you wanted to pursue physics as a career? I read that you were really into acting when you were younger.

SMITH: The interest in science happened before I got into acting. My grandmother was a biologist, and would talk to me about the articles in the New York Times Tuesday edition, the Science Times, and got me really excited about what kinds of adventures that scientists go on to answer these amazingly interesting questions. I also remember kind of the same experience that you were describing, of being exposed to certain books that really got me interested.

I remember two things in particular. One was actually during one of my acting experiences. I was an understudy for a musical. (That’s a whole other story. I don’t sing very well.) When you do work like that, the production has to get you a tutor. This was when I was in middle school, I think. So, I had a tutor, and when you have a tutor, you get your work done pretty quickly, and then the tutor thinks “Well what are we gonna do now? We’re kind of done with the schoolwork, but we still have to spend time here.” So, she gave me this book called What Do You Care What Other People Think? It was one of a pair of books by a physicist named Richard Feynman describing his life. He worked on the Manhattan Project in Los Alamos, he went to Princeton for grad school, he ended up being a professor at CalTech. He presented an image of a physicist that was curious and creative and excited, and I was hooked. I don’t even think I knew what “theoretical physicist” meant, but I thought, “That’s what I want to be.” The other thing I remember seeing a book that I couldn’t understand at the time, and seeing an integral symbol, which looks like a beautiful “S”. I remember thinking, “I want to know what that is. That’s such a beautiful, nice, long symbol, and I love drawing it. I gotta find out what this integral thing it.” For some reason that’s an important memory to me — it’s isolated in that one moment, but I guess I held some of that interest. I know what an integral is now, and I use it all the time, and it’s as amazing as I thought it was gonna be.

It was actually during an acting experience that I had this tutor who was awesome and was like “Hey, you seem interested in these things. Here’s this cool book.” That was the beginning of my interest in doing theoretical physics. It’s a good book; Richard Feynman, on the other hand, is not a nice person, it turns out. He was a hero to me, but now I’ve found out he was a bit of a jerk. But the book is still good.

REDDY: What would you say to someone that believes he or she is “not smart enough” for science?

SMITH: That’s a great question, given my interest in science communication. I would say that they are smart enough — for sure — to be exposed to some of the most unbelievable connections that we’ve found in science, if they’re open to it. I totally understand that there are people whose strengths are not quantitative. I’d say to those people that science isn’t just about being quantitative; there are stories being told. There are amazing relationships between concepts that are as deeply expressive of the scientific ideas we talk about as the equations are. There are images that are just beautiful to look at. There’s a visual side to science. I think everybody would understand that’s true — it’s true of theoretical physics, it’s true of biology, it’s true in chemistry. I guess I would say that there are many different ways of engaging with scientific concepts that aren’t just they typical ones. There’s no doubt that some of those ways will resonate with every person. It’s up to a whole bunch of different factors to expose people to all those different ways and to engage them in a way that fits their interests. I would say that if somebody is interested in science but feels that they don’t have the ability to do it, I can talk about myself. I, in no way, am — it sounds cliche, but it’s hard work. It’s dedication. I was very driven to do this. I haven’t seen many examples around me of people who aren’t just driven and interested and have great mentors. There are moving-through-life things that happen that take somebody from being interested as a seven-year-old, like I was, to sitting in an office and having this crazy thing “professor” in front of my name. When I think back to reading Richard Feynman I’m like “that’s crazy”. There is nothing really innate about that; it’s very much about feeling clear about this desire to learn these things. If that’s innate, it’s the only innate element of it.

There’s a myth out there, especially with physics, that there’s Einstein, just this singular person, just this lonely genius… FAKE, 100%. No way. Einstein had people around him that he talked to, a community of friends. His first wife helped him with the mathematics he needed to figure out special relativity and edited his papers. I don’t mean to say that she was an assistant; she was equal to Einstein in figuring out these ideas in some ways. With his friends and the kind of community he had around him, it wasn’t just him. His name is on the paper, that’s true. That is a really attractive story, because if you say it’s just one person, it’s easier to understand. But, in reality, it’s always a whole community. That’s true of everyone who goes through the process of becoming an “expert” in any field. It’s not the individual alone; it’s a whole community of people. That, to me, is empowering, and I hope it’s empowering to others who want to pursue that track to try and let go of this fear of “I have to be good enough,” that there’s this individual, innate set of abilities. I’ve not seen that. I’ve just seen people who were really dedicated and interested, who then continued to advance in studying subjects like theoretical physics. It’s important to talk about the process of learning as forming new connections. It’s not something innate. Everybody in a class is encountering new ideas for the first time. It’s all about creating connections, not about venerating some innate ability.

Featured Image Courtesy of NASA