The cambridge cosmochemistry symposium

This article is a critical summary of the solar-system aspects of a meeting held in August 1972. The purpose of the meeting was to review work done sonce the 1967 Paris meeting on the Origin of the Elements.The principal topics discussed were element abundances; the structure and composition of comets, of the terrestrial and the outer planets, of the Moon, of exospheric dust, and of meteorites; planetary atmospheres; evidence for a protosolar magnetic field from remanent meteorite magnetism, abiotic synthesis of organic molecules; nucleosynthesis; solar cosmic rays; and meteorite ages.The principal results were these: There have been a number of significant changes in the estimated solar abundances—especially D, He, B, and Fe. A great deal of progress has been made in our understanding of the temperature and pressure conditions in the protosolar nebula during planetary formation, and of the condensation of solids in it. It is believed that the bulk chemistry of the terrestrial planets is now understood on the basis of equilibrium (slow) cooling of the nebula. Their atmospheres are consistent with this model, and that of Jupiter, with inhomogeneous accretion. The structure of Jupiter is also better understood. There is disagreement on the deep structure and composition of the Moon, though of course an enormous amount has been learned, especially about the surface layers. Not so much progress has been made in understanding comets.