Session II: Internal Constitution and Thermal Histories of the Terrestrial Planets

Abstract

Hall: On behalf of the Organizing Committee of Joint Discussion A it gives me great pleasure to introduce our next speaker, Dr B. Levin. He is Chief of the Department on the Evolution of the Earth at the Schmidt Institute of Physics of the Earth at Moscow. He will present an invited paper on the Internal Constitution and Thermal Histories of Terrestrial Planets.Levin: The problems of the internal constitution of the terrestrial planets and that of their thermal histories are closely connected. We are interested not only in giving the distribution of density in planetary interiors and their stratification into physically distinct layers, but also in giving some insight into the chemical gross composition of planets. At the same time the thermal histories of the terrestrial planets strongly depend on the content of radioactive elements and thus on the chemical composition. The differentiation of planetary interiors into chemically distinct layers depends on their temperatures which determine their viscosity, but, on the other hand, the redistribution of radioactive elements in the course of differentiation seriously change the further course of the thermal history. The controversial problem of thermal convection in planetary interiors depends both on their constitution and on their thermal history.