Urey Prize Lecture: Planetary Evolution and the Origin of Life.

The origin of life appears to be closely tied to the formation and early evolution of the solar system. Key questions deal with the source of abiotic organic material on the early Earth, the nature of interstellar organic material and its relationship to the observed organic compounds in the outer solar system, and the possible origin of life on Mars early in its history. From the perspective of planetary environments, liquid water is the essential requirement for life and serves as a surrogate indicator for life. New models and analyses in conjunction with data returned from upcoming missions promise to significantly advance our knowledge of how life originated in our solar system.