Convergence Profile: Sara Seager

Sara Seager (Professor of Planetary Science and Physics, MIT) is considered a pioneer in the search for exoplanets. Her work led to the first detection of an exoplanet atmosphere, and in 2013, she was named a MacArthur Fellow.
 
PI: Scientific discoveries often happen where two or more fields intersect. What is your favourite scientific intersection,and why?
 
SS: The intersection between mathematics, physics, aerospace engineering, and astronomy. We want to find a planet like Earth, but Earth in reflected light is 10 billion times fainter than the Sun. It's nearly impossible to find another one. The Starshade appears to be our closest solution. It's a giant screen we want to put in space to block out light from the stars, so we can see the planet directly. These screens, it's a funny shape that looks like a giant flower. That shape is actually from mathematics and from the laws of diffraction. We still have a number of years of technology development ahead of us to build something very complicated, but it's something that is within reach to construct and launch into space. 
 
PI: Breakthroughs often happen at the broken places. What's the most exciting broken place for you?
 
SS: Planet formation. We thought we understood planet formation, but it was all based on our own solar system. For exoplanets, we actually see that anything is possible. We have planets closer to their star than Mercury is to the Sun, and they're big, giant planets. That whole theory was totally upended.
 
PI: What keeps you up at night, or gets you to work in the morning?
 
SS: In the quest for the search for life on other planets, what should we be looking for? It sounds like an innocent question, and until now most people focused on Earth's biosignature gases. We want to look for gases that don't belong, so we truly have to be prepared for any gas, any small molecule.
 
I recruited some biochemistry colleagues, and we embarked on this ginormous astro-informatics or chemo-informatics search to understand the limits of biochemistry of life on Earth, and what that means for life elsewhere. Using combinatorics, we constructed a giant list of molecules, and then we asked which ones are in gas form in an atmosphere that could have conditions suitable for water. The list is tens of thousands of molecules so far. It's the start of a much larger project.
 
PI: When historians look back at this moment in science, is there something you think they’ll see as obvious, that we are just missing right now, or that this time will be noted for?
 
SS: For the field of exoplanets, I think it's exceptionally historic. We're starting to realize now, just by the sheer number of people who are getting interested, at all walks of life, at all levels. Everyday talk shows, like AM-radio shows, call us now asking us to be on the show. I think people will look back at us as the generation who first found the Earth-like worlds.
 
Sara Seager will discuss Extrasolar Planets and Their Atmospheres at 4:10pm on Tuesday, June 23.