Sara Walker is a theoretical physicist and astrobiologist, researching the origin and nature of life on Earth and as it might exist on other worlds. She is Deputy Director of ASU's Beyond Center for Fundamental Concepts in Science and an Assistant Professor in the School of Earth and Space Exploration. She is also Fellow of the ASU -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.