By Karen Eng
Aomawa Shields is a woman of “contradictions.” An astronomer and astrobiologist, she searches for exoplanets where life might exist by using computer models to calculate the kind of atmosphere they’d need to support it. And she’s also a classically trained actor, who — through her organization Rising Stargirls — teaches astronomy to middle school girls of color using theater, writing and visual art to spark their imaginations.
She talks to the TED Blog about how the threads of her life — scientist, actor, role model and educator — weave together into a unique whole.
“Astrobiology” is a new word to me. What does it mean?
Astrobiology is the study of the origin, evolution, distribution and future of life in the universe. It’s a huge topic. Astrobiologists come from all different primary fields — I have an astronomy background, but there are also geologists who become astrobiologists as well as oceanographers, chemists and biologists. We’re all working together to answer the question: “Are we alone in the universe?” And also: “How do we go about answering that question?”
Some of these experts focus on the origin of life: How did life even get started on our planet? Others think about metabolism: How does life evolve, use its energy and carry out the reactions that it needs to feed, grow, reproduce and respond to its environment? Are there different kinds of metabolisms besides what we know here on Earth that life could use? It’s important to ask that question, because we don’t want to miss out on discovering life because it uses different chemical processes from life as we know it, or because it is not carbon-based, or because it uses something besides water to carry out molecular processes.
We have all these planets that have been discovered, but we can’t look at all of them in detail to try to measure their atmospheric composition and determine if there’s life there. So I’m a big proponent of using a combination of observational astronomy and theoretical astronomy techniques to help us narrow in on the planets most likely to have water and life. Finding them is the first step, and it’s an important, crucial step — but it’s not the whole story. Identifying a planet as “potentially habitable” does not mean it’s “habitable,” and “habitable” does not mean “inhabited.” That’s something that the public can get really confused by.
Your approach is to do climate modeling on exoplanets. How does this work, and what does it tell us about the potential for life out there?
I modify climate models originally developed for the Earth — three-dimensional global climate models that are used to forecast weather and climate patterns — and apply them to planets orbiting different kinds of stars. The idea is to try to pin down whether these new planets we’re discovering might be habitable. For example, different types of stars emit light in different ranges of the spectrum. Cooler stars emit a lot more light at longer wavelengths, and ice and atmospheric gases strongly absorb that type of light. So planets orbiting those types of stars might tend to be warmer compared to planets orbiting other types of stars. That’s what some of my work suggests. By looking at the combination of factors that can influence the climate of a planet, we can try to determine the conditions necessary for that planet to be hospitable for life.
My work will help decide which planets to put at the top of the priority list to look at once the next generation of telescopes become available, as it’s those new missions that will allow us to go looking for the atmospheric fingerprints of life on a planet. This is important because we don’t have infinite telescope time, and we’ve got thousands of planets discovered so far — and quite a long list of those are actually in what we call the “Goldilocks zone,” where they might not be too warm or too cold to host life.
As a modeler, I can determine what the surface temperature would be if the atmosphere of a planet has a certain composition. My work mantra is: “The Goldilocks zone is not the be-all and end-all.” You can have a planet that is at the right distance from a star but that still isn’t habitable, because there are all sorts of other factors that could make it uninhabitable — the shape of its orbit, for instance, could create extreme temperature fluctuations over the course of its year as it goes around its star. We need to explore the wide range of factors that can affect the climate and habitability of a planet, so we have an accurate assessment of a planet’s prospects for life.
What kinds of planets would you prioritize?
If a planet is warm enough for water, no matter what, I throw it in my model universe. I would put it at the top of the list, because it would take a lot for it not to be habitable. Still, that doesn’t mean it actually has water. We’re trying to get large telescopes to hone in on the atmosphere and look for indicators of, perhaps, some sort of ocean. Colleagues of mine are studying ways to detect the glint of starlight reflected from an ocean on an exoplanet. The thing is: the glint might not even be water. Saturn’s moon Titan, for example, has lakes of liquid ethane, and we can detect the glint on those. So if there’s life there, it would be life like nothing we know of.
What else do you look for in a planet?
Astrobiologists also explore possible false positives for life. For example, you might assume that if you detect oxygen in an atmosphere, it means there’s life on the planet. Well, volcanoes can make oxygen — they expel carbon dioxide, which is carbon and oxygen, and that can get broken up by sunlight. So if you detected the oxygen you might think there’s life there when there’s not.
One task is to generate a list of false positives, so that we can check those off. It’s a tough question: How can we tell, unequivocally, that a planet has life on it, without physically going there? Because that’s probably not going to happen in our lifetimes. But getting a telescope up in space that could measure these atmospheric constituents? That could happen in our lifetime, so we want to know exactly what to look for.
My work is leading up to that. I’m helping to generate that list of prioritized planets so that we will be able to say, “Okay, these planets are most likely to succeed. Let’s point the telescopes there.” I think it’s a crucial step in this search.
You’re an actor as well as an astrobiologist. Those are two extremely time-consuming and al-absorbing disciplines. How did you pull that off?
I actually left astronomy for 11 years. I started off at MIT and studied earth, atmospheric and planetary sciences, and got my bachelor’s degree. I started a PhD program in astrophysics right out of undergrad. I had also applied to a couple of acting grad schools, though nothing came of that. And yet acting was always a pull, so when things got challenging academically during that first year, I thought, “Let me try this acting and see what happens.”
I deferred from the astrophysics program and went to UCLA for theatre — and the whole world opened up. Acting felt like playtime, because they were having us do things like find a favorite poem and bring it in to share with the class — and then act it out. We got to write our own one-person show. It was hard in a very different way, and extremely terrifying.
But after receiving my acting degree, I realized I missed astronomy. I didn’t want to hear about discoveries on the TV news with everyone else — I wanted to be part of it. I took a day job at Caltech, as a helpdesk operator for the Spitzer Space Telescope, which is like Hubble, but looking at the universe through infrared eyes instead of visible eyes. Someone there knew I had an acting background, and when PBS came knocking — which they tend to do at Caltech when they need science hosts — I got an audition as co-host for a science news magazine, Wired Science, a partnership between PBS and Wired magazine. And I got the job.
Gradually, I fell back in love with the field. Science television really seemed to put both of my worlds — acting and astronomy — together. Suddenly it started to feel like all roads led back to getting my PhD in astrophysics. Through Caltech, I was put in contact with Neil deGrasse Tyson, and he told me that I needed a PhD to be seen as an expert on TV. I also applied to the NASA Astronaut Candidate Program around that time, and a PhD was necessary to advance to the next level there too. So I took the leap and went back for my astrophysics PhD at the University of Washington. My husband’s willingness to move to Seattle, and his support throughout grad school, were instrumental to my success.
You’ve also synthesized acting and astronomy in your work with girls and STEM education. What was the inspiration for this work?
I wanted to encourage more girls from backgrounds traditionally underrepresented in the sciences to consider astronomy careers. But I didn’t want to teach them astronomy in a conventional, lecture-based way — or even do typical hands-on astronomy activities. I wanted to use my unique background.
My workshop, which is called “Universe: More than Meets the Eye,” aims straight for the fact that girls, when they’re in middle school, start to get quiet. They start to raise their hands less often, and become overly concerned with how they appear to others — how pretty they look, what’s on the outside — and less concerned with what they’re thinking and feeling. But there’s so much more to them than that, and whether they can learn facts about planets. I thought, “Let’s take a multifaceted approach to astronomy.” I was lucky to have funding from the National Science Foundation, which values this kind of outreach work just as highly as my research.
The workshop incorporates writing, theater games and visual art. We ask the girls to imagine. For example, we’ll ask them to draw their own exoplanet, and make choices about that planet. Is it too hot or too cold for life? If it does have life, what kind of life would it have? What do you want it to look like? How many stars does it orbit? When a girl says to me while she’s drawing, “What if we discover a planet that actually looks like what I’m drawing?” it’s wonderful to be able to say, “We could! We really could. We’re finding crazy planets out there.” That interaction means she’s thinking about her own relationship to the subject.
From there, I got the idea to take this work to different schools. I just finished doing a workshop at Irving STEAM Magnet Middle School in Los Angeles. The school is 80% Hispanic, and the girls that participated in the workshop were Hispanic. Over three weeks, we met twice a week after school for two hours. At the end, they said, “Why do you have to leave?” I asked them to rate their level of agreement with the statement: “I see myself as a science person” on a scale of 1 (strongly disagree) to 6 (strongly agree) before and after the workshop. Before the workshop, only 20% of the girls answered with a 4 or higher. After the workshop, more than 60% selected a 4 or higher. Those are encouraging results.
If I can get girls to see a piece of themselves — their hair, a foot, their face and eyes, a finger — as connected to an exploding star, maybe that connection will stay with them as they start to encounter the inevitable challenges of a science career. So they won’t turn their backs on it when things get tough.
You seem to be pulled strongly in many directions at once.
Yes, I am. But I’m also realizing that maybe I don’t have to think in such either/or terms. One of the greatest things to come out of my experience with TED is the understanding that we are all potentially walking contradictions. Another member of my TED cohort noted that the contradiction is only in how we might be perceived by others. In reality, that’s just how humans are. We have so many different facets.
I’m a champion of: “It’s never too late to be what you might have been.” I was 34 years old when I started grad school in astronomy the second time around. And I was so much better prepared for it as a result of my age — mentally, emotionally and spiritually. There’s a way to be involved in the thing that you always loved to do. And my tagline on my website is: “There’s no one way to be a scientist.” Really, there’s no one way to do anything. Just because there’s no one who’s gone before me that has done it doesn’t mean that it can’t be done. My only limitations are my own mind, really.