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Sara Walker

Associate Professor
Faculty, TEMPE Campus, Mailcode 6004
Associate Faculty
Faculty, TEMPE Campus, Mailcode 6004
Associate Director, ASU-SFI Center
Faculty, TEMPE Campus, Mailcode 6004
Deputy Director of the Beyond Center
Faculty, TEMPE Campus, Mailcode 6004
Associate Professor
Faculty, TEMPE Campus, Mailcode 6004
Associate Professor
Faculty, TEMPE Campus, Mailcode 6004
Associate Professor
Faculty, TEMPE Campus, Mailcode 6004
Biography

Professor Sara Walker is an astrobiologist and theoretical physicist interested in the origin of life and how to find life on other worlds. While there are many things to be solved, she is most interested in whether or not there are ‘laws of life’ - related to how information structures the physical world - that could universally describe life here on Earth and on other planets.

At Arizona State University she is Deputy Director of the Beyond Center for Fundamental Concepts in Science, Associate Director of the ASU-Santa Fe Institute Center for Biosocial Complex Systems and Assistant Professor in the School of Earth and Space Exploration. She is also 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 appearances at the World Science Festival and on "Through the Wormhole" and NPR's Science Friday.

Education

Dartmouth College, Ph.D., Physics and Astronomy (2010)

Florida Institute of Technology, B.S., Physics (2005)

Cape Cod Community College, A.A. Math/Science/Pre-Engineering (2003)

Research Interests

origins of life, physics of life, artificial life, complex systems, astrobiology, theoretical physics, exoplanets, intelligence, biosignatures

Research Group

Our team's research is motivated to uncover the fundamental principles explaining life, including its origins.  That is, we seek to answer the question "What is Life?" by identifying whether there are laws of life. Our idea is that if there are universal laws that describe living systems on Earth and elsewhere, these should ultimately have something to do with information and how it structures physical reality. 

We look at life across all scales of biological organization from cells to civilizations, on Earth and beyond to answer:

What is life?
We study collective behavior in a variety of living systems, from gene regulatory networks to ant colonies, to determine how information structures matter in living systems. 

How did life get started?
We are developing new theory for how life can emerge from non-living matter based on the idea that information plays a critical role in the transformation of matter to life.

Are we alone?
We are working on new ways of thinking about the search for life on other worlds, building quantitative criteria for identifying life.

Publications

Selected Recent Publications:

  1. D. Moore** and S.I. Walker (2019) Inferring a Graph’s Topology from Games Played on It. Proceedings ALIFE 2019: The 2019 Conference on Artificial Life, pp. 271–277. [online]
  2. S.I.Walker (2019) The new physics needed to probe the origins of life. Nature 569, 36-38. [online]
  3. A.J. Surman, M. Rodriguez-Garcia, Y.M. Abul-Haija, G.J.T. Cooper, P.S. Gromski, R. Turk-MacLeod, M. Mullin, C. Mathis*, S.I Walker and L. Cronin (2019) Environmental control programs the emergence of distinct functional ensembles from unconstrained chemical reactions. Proceedings of the National Academy of Sciences 116, no. 12: 5387-5392. [online]
  4. H. Kim**, H.B. Smith*, C. Mathis*, J. Raymond and S.I. Walker (2019) Universal scaling across biochemical networks on Earth. Science Advances 5: eaau0149. [online]
  5. B. Daniels, H. Kim**, D. Moore**, S. Zhou*, H.B. Smith*, B. Karas*, S.A. Kauffman, and S.I. Walker (2018) Criticality Distinguishes the Ensemble of Biological Regulatory Networks Phys. Rev. Lett. 121, 138102. [online]                     
  6. D. Moore**, G.Valentini**, S.I. Walker and M. Levin (2018) Inform: Efficient Information-theoretic Analysis of Collective Behaviors. Frontiers in Robotics and AI. doi: 10.3389/frobt.2018.00060
  7. G.Valentini**, D.Moore**, J.Hanson*, T.P. Pavlic, S. Pratt and S.I Walker (2018) Transfer of Information in Collective Decisions by Artificial Agents. Proceedings of ALIFE 2018: The 2018 Conference on Artificial Life, pp. 641–648. [online]
  8. S.I. Walker, W. Bains, L. Cronin, S. DasSarma, S. Danielache, S. Domagal-Goldman, B. Kacar, N.Y. Kiang, A. Lenardic, C.T. Reinhard, W. Moore, E. Schwieterman, E. Shkolnik and H.B. Smith* (2018) Exoplanet biosignatures: future directions. Astrobiology18(6), pp.779-824. https://doi.org/10.1089/ast.2017.1738 
  9. N.Y. Kiang, S. Domagal-Goldman, D.C. Catling, Y. Fuji, V.S. Meadows, E. Schwieterman and S.I. Walker (2018) Exoplanet Biosignatures: At the Dawn of a New Era of Planetary Observations. Astrobiology 18(6) 619-629  http://doi.org/10.1089/ast.2018.1862
  10. E.W. Schwieterman, N.Y. Kiang, M.N. Parenteau, C.E. Harman, S. DasSarma , T.M. Fisher*, G.N. Arney, H.E. Hartnett, C.T. Reinhard, S.L. Olson, V.S. Meadows, C.S. Cockell, S.I. Walker, J.L. Grenfell, S. Hegde, S. Rugheimer, R. Hu, and T. W. Lyons (2018) Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life. Astrobiology 18(6): 663 - 708 http://doi.org/10.1089/ast.2017.1729
  11. S.I. Walker, N. Packard and G. Cody (2017) Re-Conceptualizing the Origin of Life. Phil. Trans. Roy. Soc. A.  375:20160337 [online]
  12. W. Marshall, H. Kim**, S.I. Walker, G. Tononi, and L. Albantakis (2017) How Causal Analysis Can Reveal Autonomy in Models of Biological Systems. Phil. Trans. Roy. Soc. A.  375:20160358 ​  [online]
  13. C. Mathis*, S. Ramprasad, S.I. Walker, and N. Lehman (2017) Prebiotic RNA Network Formation: A Taxonomy of Molecular Cooperation. Life 7(4):38. [online]
  14. E. Borriello** and S.I. Walker (2017) An Information Theoretic Classification of Elementary Cellular Automata. Complexity. Article ID 1280351. [online] [preprint]
  15. D. Moore**,  S.I. Walker, and M. Levin (2017) Cancer as a Disorder of Patterning Information: computational and biophysical perspectives on the cancer problem. Convergent Science Physical Oncology. 3(4): 043001. [online]
  16. A. Adams*, A. Berner*, P.C.W. Davies and S.I. Walker (2017) Physical Universality, State-Dependent Dynamics and Open-Ended Evolution. Entropy. 19(9): 461.  [online]  (cover article)
  17. S.I. Walker (2017) Origins of Life: A Problem for Physics, A Key Issues Review. Reports on Progress in Physics.  80(9): 092601 [online] arxiv:1705.08073
  18. A. Adams* and S.I.Walker (2017) Real-world Open-ended Evolution: A League Of Legends Adventure. International Journal of Design & Nature and Ecodynamics 12: 458-469.
  19. A. Adams*, H. Zenil, P.C.W. Davies and S.I.Walker (2017) Formal Definitions of Unbounded Evolution and Innovation Reveal Universal Mechanisms for Open-Ended Evolution in Dynamical Systems. Scientific Reports. 7: 997. [preprint] arxiv:1607.01750 [online]
  20. C. Mathis*, T. Bhattacharya and S.I. Walker (2017) The Emergence of Life as a First Order Phase Transition. Astrobiology 17(3): 266-276. [online] [preprint] 
Fall 2019
Course NumberCourse Title
AST 498Pro-Seminar
AST 591Seminar
SES 692Research
SES 792Research
PHY 792Research
SES 799Dissertation
Summer 2019
Course NumberCourse Title
PHY 792Research
Spring 2019
Course NumberCourse Title
SES 311Essentials of Astrobiology
SES 494Special Topics
SES 598Special Topics
SES 692Research
SES 792Research
PHY 792Research
SES 799Dissertation
PHY 799Dissertation
Fall 2018
Course NumberCourse Title
SES 106Habitable Worlds
SES 692Research
PHY 792Research
SES 792Research
SES 799Dissertation
Summer 2018
Course NumberCourse Title
SES 692Research
PHY 792Research
SES 792Research
SES 799Dissertation
Spring 2018
Course NumberCourse Title
SES 311Essentials of Astrobiology
SES 692Research
SES 792Research
PHY 792Research
SES 799Dissertation
PHY 799Dissertation
Fall 2017
Course NumberCourse Title
GLG 460Astrobiology
SES 499Individualized Instruction
SES 692Research
SES 792Research
PHY 792Research
SES 799Dissertation
PHY 799Dissertation
Summer 2017
Course NumberCourse Title
SES 692Research
PHY 792Research
SES 792Research
SES 799Dissertation
Spring 2017
Course NumberCourse Title
SES 499Individualized Instruction
GLG 592Research
AST 592Research
GLG 599Thesis
SES 692Research
GLG 692Research
AST 692Research
SES 792Research
AST 792Research
PHY 792Research
GLG 792Research
SES 799Dissertation
GLG 799Dissertation
AST 799Dissertation
Fall 2016
Course NumberCourse Title
AST 113Astronomy Laboratory I
GLG 592Research
GLG 599Thesis
SES 692Research
GLG 692Research
AST 692Research
PHY 792Research
GLG 792Research
AST 792Research
SES 792Research
SES 799Dissertation
GLG 799Dissertation
AST 799Dissertation
Summer 2016
Course NumberCourse Title
GLG 592Research
AST 692Research
PHY 792Research
GLG 799Dissertation
Spring 2016
Course NumberCourse Title
SES 494Special Topics
SES 591Seminar
AST 592Research
GLG 592Research
SES 598Special Topics
GLG 599Thesis
GLG 692Research
AST 692Research
AST 792Research
PHY 792Research
GLG 792Research
GLG 799Dissertation
AST 799Dissertation
Fall 2015
Course NumberCourse Title
AST 111Intro/Solar Systems Astronomy
GLG 592Research
GLG 599Thesis
AST 692Research
GLG 692Research
PHY 792Research
AST 792Research
GLG 792Research
AST 799Dissertation
GLG 799Dissertation
Summer 2015
Course NumberCourse Title
GLG 592Research
PHY 792Research
Spring 2015
Course NumberCourse Title
AST 113Astronomy Laboratory I
GLG 592Research
AST 592Research
GLG 599Thesis
AST 692Research
GLG 692Research
PHY 792Research
AST 792Research
GLG 792Research
AST 799Dissertation
GLG 799Dissertation