March 18, 2022
Time and again, the indescribable foreignness of other worlds in our solar system has far surpassed our expectations and left us reconsidering what we thought we knew of our universe. And yet, as we search for life, our detection methodologies and biological expectations often presume that the life we are seeking is similar to the life we know from Earth: we rely primarily on the identification of well-established and widely accepted features associated with terran life, and on signatures of biologic processes such as particular classes of molecules and patterns within the molecular weights of fatty acids or other lipids. So, how might we contend with the truly alien? How might we break free from our ideas about “life as we know it,” and search instead for “life as we don’t know it?” This talk will examine the search for life from the dawn of the space age, address new approaches to life detection, and consider the relevance of these techniques for the exploration of places like Mars and the icy moons of Jupiter and Saturn.
Sarah Stewart Johnson grew up in Kentucky before becoming a planetary scientist. She is now the Provost’s Distinguished Associate Professor at Georgetown University, where her research is driven by the underlying goal of understanding the presence and preservation of biosignatures, or traces of life, within planetary environments. Her lab is also involved in the implementation of planetary exploration, analyzing data from current spacecraft and devising new techniques for future missions. A former Rhodes Scholar and White House Fellow, she received a B.A. from Washington University in St. Louis, a second B.A. and M.Sc. from Oxford University, and a Ph.D. from MIT before completing a postdoctoral fellowship with the Society of Fellows at Harvard University. She has participated on the science teams for NASA’s Spirit, Opportunity, and Curiosity Rovers, and since 2016, has been a visiting scientist with the Planetary Environments Lab at NASA’s Goddard Space Flight Center. Since 2018, she has also served as the Principal Investigator of the $7M Laboratory for Agnostic Biosignatures, a NASA-funded research project designed to search for “life as we don’t know it.” She also loves to write. Her writing has appeared in the New Yorker, The New York Times, The Los Angeles Times, The Harvard Review, and the Best American Science and Nature Writing. Her first book, The Sirens of Mars: Searching for Life on Another World, was selected as one of The New York Times's 100 Notable Books of 2020, and in 2021, she received the Whiting Award for Nonfiction, the largest US literary award for emerging writers.