He graduated from Swarthmore College in 1982, and studied mathematical physics at the University of Cambridge as a Marshall Scholar. He then received his Ph.D. in Astronomy, with an emphasis in Planetary Science, from Cornell University in 1991. He was a White House Fellow on the National Security Council staff, and then serving in the Office of Science and Technology Policy (OSTP) from 1993 to 1995. He was a member of the SETI Institute Board of Trustees from 2005 - 2007.
- "Commencement Address", June 1, 2003
- "Contingency and the Cosmic Prospective", The new astronomy: opening the electromagnetic window and expanding our view of planet earth, Editor D. Wayne Orchiston, Springer, 2005, ISBN 978-1-4020-3723-8
- Comets and the origin and evolution of life, Editors Paul J. Thomas, Christopher F. Chyba, Springer, 2006, ISBN 978-3-540-33086-8
- U.S. nuclear weapons policy: confronting today's threats, Editors George Bunn, Christopher F. Chyba, William James Perry, Center for International Security and Cooperation, Freeman Spogli Institute for International Studies, Stanford, Calif., 2006, ISBN 978-0-8157-1365-4