Dr. Emma Bakes

December 19, 2006

“A Prebiotic Photochemical Study of Early Earth”

NNG05GQ68A 

A hydrocarbon haze such as is evident around Saturn’s largest moon, Titan, dominates the host planet’s atmospheric temperature, circulation and climate control.  This haze is postulated to have existed via methane photolysis in the atmosphere of the early Earth.  In this project photochemical models of the Titan haze which were built in previous research by the PI and collaborators, will be adapted in order to understand chemical processes important for the formation of nitrogenated aerosols and macromolecules in the reducing atmosphere of early Earth.  Models of hydrocarbon haze charging and infrared (IR) emission will be used to analyse chemical and IR spectral data from laboratory-based simulations of the primitive terrestrial atmosphere.  How a hydrocarbon haze might have shielded important greenhouse gases, such as ammonia, and how these gases might have contributed to the heating of the atmosphere via the photoelectric ejection of energetic electrons (which might mitigate the anti-greenhouse effect introduced by the haze as it is a powerful heating mechanism) is being investigated.  The goals of this project are:  1) to adapt existing models to physical conditions (UV field, electron density and gas temperature) appropriate to the primitive atmosphere of the early Earth; 2) to support complementary laboratory work analyzing the macromolecular and submicron aerosol components postulated to exist in this environment; and 3), to investigate the relevance of our photochemically produced nitrogenated heterocycles to prebiology.  They form the foundations of cellular metabolism and reproduction and by investigating their formation pathways, we can understand the bridge between prebiological chemistry and biochemistry.