MacArthur Fellows Program

Sara Seager

Astrophysicist | Class of 2013

Adapting fundamental maxims of existing planetary science to create a comprehensive theoretical framework for determining the characteristics of planets beyond our solar system.

Massachusetts Institute of Technology
Cambridge, Massachusetts
42 at time of award
Published September 25, 2013

About Sara's Work

Sara Seager is an astrophysicist and planetary scientist exploring the possibility of life throughout the galaxy. Adapting the principles of existing planetary science to the study of exoplanets (planets outside the solar system), she is quickly advancing a subfield initially viewed with skepticism by the scientific community. A mere hypothesis until the mid-1990s, nearly 900 exoplanets in more than 600 planetary systems have since been identified, with thousands of more planet candidates known.

Early in her career, Seager determined that the nature of an exoplanet’s atmosphere could be observed during an eclipse, when the planet’s atmospheric light spectrum is especially distinct from its much brighter host star. She then envisioned and formalized a comprehensive framework for guiding and interpreting observations of planets in this manner, including parameters for calculating planet density and remotely detecting biosignature gases (spectroscopic signatures of chemical compounds that are indicative of life) in their atmospheric spectra. Her early predictions led to the first detection of an exoplanet atmosphere by observations from the Hubble Space Telescope.

While continuing to create and refine theoretical models of exoplanet atmospheres and interiors, she is also spearheading advanced hardware design and space mission projects, including ExoplanetSat, a university collaboration to build low-cost “nano-satellites” to observe planetary transits. ExoplanetSat is a new concept for space science: a fleet of dozens of cheap copies of an ultra-small space telescope that will open up a new avenue for wide-ranging space exploration. A visionary scientist contributing importantly in every aspect of her field, Seager is finding new celestial frontiers and fueling curiosity about life in worlds beyond our reach.


Sara Seager received a B.Sc. (1994) from the University of Toronto and a Ph.D. (1999) from Harvard University. She was affiliated with the Institute for Advanced Study (1999–2002) and the Carnegie Institution of Washington (2002–2006) before joining the faculty at the Massachusetts Institute of Technology, where she is Class of 1941 Professor in the Department of Earth, Atmospheric, and Planetary Sciences and the Department of Physics. She is the author of Exoplanet Atmospheres and Exoplanets (both 2010).

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Please credit: John D. and Catherine T. MacArthur Foundation

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