The prebiotic atmosphere of the Earth

Because of the paucity, of geologic samples dating back to the early,7 Earth, trying to unveil the nature of the prebiotic terrestrial environment is as frustrating as it is fascinating. An understanding of the characteristics of this period in our planet's history is. however. crucial to studies of the origin of Life. Recent. progress in astrophysics,geochemistry, and simulation of planetary accretion provide some new and precious constraints but also question some of the previously,7 admitted "facts". The aim of this chapter is to highlight. some of the important, open-ended questions about the environment of the prebiotic Earth (for a. more comprehensive review, see Kasting and Gatling, 2003). The implications of recent theories of terrestrial planets formation on the origin and early, evolution of the atmosphere are discussed, in particular. along with the various influences of our faint but active young Sun during this period.