Sara Imari Walker is a theoretical physicist and astrobiologist. She is an Assistant Professor in the Beyond Center for Fundamental Concepts in Science in the School of Earth and Space Exploration, Arizona State University. She is also a Fellow of the Arizona State University-Santa Fe Institute Center for Biosocial Complex Systems, co-founder of the astrobiology-themed social website SAGANet.org, and is a member of the Board of Directors of Blue Marble Space. She is active in public engagement in science, with recent appearances on 'Through the Wormhole' and NPR's Science Friday.