Prebiotic-Related Chemistry in the Present Outer Solar System

Abstract

AbstractThere are numerous places in the outer solar system where the formation of the starting ingredients which are involved in the early terrestrial prebiotic chemistry is currently going on. Organic chemistry is largely present in the outer planets, particularly in Titan. Titan has a dense atmosphere, mainly composed of N2and CH4and very rich in organic compounds, both in gas and aerosol phases. Because of the low temperature of Titan’s environment, liquid water is currently absent from the satellite and compounds of low stability at the (Earth) laboratory temperature, and very reactive, are still or may be present. However, Titan study should provide information on prebiotic chemistry – at least prebiotic chemistry in absence of liquid water. This quasi-planet thus appears as a natural laboratory enabling to study prebiotic evolution toward complex organic systems in a planetary environment over a long time scale. A detailed study of such a natural prebiotic laboratory is precisely one of the main objectives of the Cassini-Huygens mission. With the sending of the Cassini orbiter around Saturn and the Huygens probe in the atmosphere of Titan, this mission, due to be launched in October 1997, for a Saturn arrival in 2004, will offer a unique opportunity to study in detail extra-terrestrial prebiotic processes, together with important implications in the field of bioastronomy and the origins of life.