Origins’ Amanda Preston and former Harvard graduate student, Sarah Rugheimer met to discuss Sarah’s origins research. Sarah received her Ph.D. in January 2015 and is now a Simons Postdoctoral Research Fellow at the University of St. Andrews.
Amanda: Sarah, can you tell me us briefly how your thesis topic connects to origins of life research?
Sarah: My thesis topic revolves around studying the biomarkers and modeling the atmospheres of extrasolar planets. I am particularly interested in how we can detect indicators of life on an extrasolar planet – remotely from Earth – using space-based telescopes. And so my thesis revolves around modeling Earth-like planet atmospheres and the detectability of their features, i.e., how you would detect ozone, oxygen, methane, nitrous dioxide, and similar features which in combination indicate life. How easy are they to detect? And in what quantities do they need to be present, in order for us to be able to detect them and therefore what instruments and what size of telescope do we need? This will provide future instrument requirements as well as the telescope size and what wavelengths observers should prioritize. It is important to consider which features are unique, what features overlap, and how the planet’s star type, size, orbital parameters etc affects the visibility of those features.
Amanda: And this would be based on Earth chemistry?
Sarah: Yes, we base our model on 1-D Earth-based models, and using the underlying physics, expand them to other rocky planets.
Amanda: Do you have colleagues who are thinking about whether there would be other biochemistries, and how one might detect life, assuming that it’s not an Earth analog?
Sarah: So I guess that’s a two-part question. One is, there's the Earth analog, which is oxygen, methane – carbon-based chemistry. First you test your models assuming a direct Earth-analogue, assuming Earth-like clouds, an Earth-like composition, and a solar-type star. So you can be very extreme in your Earth-like assumptions to start. Then, you can expand those a little bit and examine how different clouds affect the detectable spectrum or how a different host star influences the planet’s atmosphere. You can model what a planet’s spectrum would be like if a different set of microbes would dominated its atmosphere. As far as I know, we don’t know enough about non-carbon based life to predict what atmospheric biosignature features it would produce and therefore what we could detect.
Amanda: What are the big challenges in doing this atmospheric modeling?
Sarah: Well, I think the biggest challenge is, because we only know one planet with life, the data we use to verify our models are very Earth-centric. And it’s difficult when you start veering too far away from Earth to put any sort of errors on your estimates. Until we get more observations of extrasolar planets and also learn more about our own solar system, it’s difficult to know how accurate your models are.
Amanda: How did this puzzle capture your imagination? How did you start out doing astronomy and astrophysics, much less the work that you're doing now?
Sarah: I have said a lot of “nevers” in my life. I was never going to take a physics course because my dad was a physicist, and my brother is a physicist. When I found myself in an accounting class in high school that was really boring, the only class I could switch into was physics. And so I ended up taking physics. I really liked it but still swore never to major in physics. After graduating high school, I was thinking about what else I could major in. I had an epiphany a week before classes started, that it was really dumb not to major in something just because most of my family was in it. After that epiphany I was open to realizing that physics was my favorite subject and in the end, I majored in physics as an undergrad. But in undergrad, I never took an astronomy class. I never went to an astronomy colloquium. I never did anything with astronomy until my last undergraduate research experience in Hawaii. I remember after the program my advisor asked me if I would consider becoming an Astronomer. That year when a professor in Calgary asked if I would work on a spectra project I turned him down because I thought looking at “squiggly lines” all day was boring. Then I went to the summer American Astronomical Society (AAS) conference.
At the AAS, I sat in on the astrobiology section. I had never heard anything more exciting. Finally science is beginning to being able to start answering humanity’s most fundamental questions of how we got here, and is there life elsewhere in the Universe? Are we alone? These are basic fundamental questions we have been thinking about for thousands of years.
That’s what really drew me to astronomy and studying atmospheric spectra, similar to the project I turned down in undergrad. I started reading books on astrobiology. I read Robert Hazen’s Genesis: The Scientific Quest for Life’s Origin and listened to the Teaching Company’s Origin of Life lecture series. The more I read, the more interested I got. I never have doubted my path from that point. Astrobiology is really what inspired me to want to be a scientist and my life’s passion.
Amanda: What advice would you give someone in high school, or college, who is contemplating a career in science, or more specifically, a career in astronomy or astrophysics? How best would someone prepare? It sounds like your pathway is kind of unconventional.
Sarah: Firstly, I think there are a lot of reasons people come up why not to do science. Social pressure comes from scientists still being depicted as socially awkward and/or nerdy on TV and in movies. I think people should really ignore those reasons. When I look around I see a wide variety of people who are also passionate about their work.
Amanda: What do you mean by social pressure?
Sarah: For example, females in science. There are often comments made by either your family, friends, or professors, even, other colleagues that can be discouraging to budding females scientists. I remember being told by a professor “you are pretty smart for being a girl.” Ultimately I think girls should be encouraged to pursue their passions for science since studies have shown that innately males and females have similar level of interest in science (Carothers & Reis, 2012). For males in science, I think they obviously should keep going into science. For males, I think particularly, if I had to say one thing, it would be to be aware of the bias against females and minorities still exists (Moss-Racusin et al., 2012). I think the only way to reduce the gender gap is for upcoming males to be aware that bias still exists and to take it seriously and help make the work place equal opportunity for everyone.
I think everyone should be at least peripherally interested in science – we all use cell phones, TVs, cameras etc. - and we need to encourage people to pursue careers in science, technology, and engineering. I think science and technology is the best way for the U.S. to maintain a stable economy and to be competitive in the world. Pursuing any career in science, even a “non-practical” science like astronomy, is beneficial to society as a whole, because basic research often leads to development of new technology and gets trickled down to services we take for granted like smoke detectors or tennis shoe material (both originally from NASA). In addition, having a scientifically literate population is vitally important as we tackle political questions like how to address climate change and science education.
Amanda: How do you see your future? Will you be teaching in a university?
Sarah: That is something I have been thinking a lot about recently. I love my research, and I specifically like teaching science at an undergraduate level. For many people, they’ll only take a few science classes in college, maybe only one. One of the most important things that teachers can pass on to their students is an understanding of the scientific process and help them to become scientifically literate citizens.
Amanda: We live in a world that is increasingly specialized. Is it possible to launch a career, as a young person in science, that isn't already specialized by the time you get your Ph.D.?
A: I think astrobiology is a great example to talk about in regard to this question. To be a researcher that’s interested in astrobiology, you have to specialize, but you also have to be somewhat of a generalist. You have to know concepts from biology, chemistry, geology, astronomy, physics and all areas of science. So, at some level, I'm definitely way less specialized than most of my colleagues here in the graduate program but my view is broader and in addition encompasses new research in different interdisciplinary areas.
I think that is a unique aspect of astrobiology. Multidisciplinary science, in my opinion, is the future. Nature doesn’t distinguish between these different disciplines like we do. It’s when people learn about multiple areas of science that they're able to see new connections and form new paradigms and ways of looking at things. Many of the advances we see now are in areas like biophysics or medical physics, where the crossing over of disciplines is already happening. The borders are getting very muddled.
In the end, while you do get specialized in your specific research area, it’s important to just have a solid science background.
Amanda: So “muddled” is maybe a good thing?
Sarah: Muddled …. interdisciplinary, multidisciplinary. It’s having origins of life centers like here at Harvard, where scientists from different disciplines are talking, that opens up new areas of research and new ways of looking at things.