Science Matters Lecture Series, 2020-2021

The Search for Life on Mars

Recorded on Wednesday, February 24, 2021

An online community event featuring Dr. Sarah Johnson of Georgetown University and Dr. Carol Cleland of the University of Colorado, Boulder.

Exciting new research is attempting to find evidence for either extinct or existing life in the universe.  Previous Mars missions found that liquid water existed on Mars in the distant past, raising the question of whether there might be evidence for extinct life. The Curiosity rover, which landed on Mars in 2012, explored the “habitability” of Mars. It found nutrients and energy sources that microbes could have used and established that Mars indeed had regions that could have been friendly to life in the ancient past. The Perseverance rover, launched in July 2020 and landing on Mars in February 2021, will take the next step by looking for the signs of past life itself. At the same time, other nations are joining the search for life on Mars, and new technologies are paving the way for life detection missions to the far reaches of the solar system. 

What sort of evidence of life are scientists looking for and what methods are they employing?  Are these methods too Earth-centric? What would constitute compelling scientific evidence for an unfamiliar form of life?

Sarah Johnson

Associate Professor of Planetary Science, Georgetown University

Sarah Johnson's research group focuses on detecting biosignatures, or traces of life. It analyzes data from current spacecraft and devises new techniques for future missions. A former Rhodes Scholar and White House Fellow, she received her Ph.D. from MIT and has worked on NASA's Spirit, Opportunity and Curiosity rovers. She is also a visiting scientist with the Planetary Environments Lab at NASA's Goddard Space Flight Center. She is the author of The Sirens of Mars: Searching for Life On Another World, which was a New York Times Editor's Choice and one of the New York Times 100 Notable Books of 2020.

Carol Cleland

Professor of Philosopy and Director of the Center for the Study of Origins, University of Colorado, Boulder

Carol Cleland is affiliated with the NASA Center for Astrobiology and a member of CU's Center for Astrobiology. Specializing in the philosophy of science, Dr. Cleland is the author of The Quest for a Universal Theory of Life: Searching for Life As We Don’t Know It (Cambridge University Press, 2019). In addition, she is the co-author with Mark Bedau of The Nature of Life: Classical and Contemporary Perspectives from Philosophy and Science (Cambridge University Press, 2010 and reprinted in paperback in 2018). Dr. Cleland has published extensively in both philosophy and science journals. Most recently, she has been working with Robert Hazen on developing a more historically taxonomy of mineral species for planetary science. She is also working on a new book on the role of anomalies in scientific discovery.