SP-345 Evolution of the Solar System




The present analysis of the origin and evolution of the solar system represents a fusion of two initially independent approaches to the problem. One of us (Alfvén) started from a study of the physical processes (1942, 1943a, 1946; summarized in a monograph in 1954), and the other (Arrhenius) from experimental studies of plasma-solid reactions and from chemical and mineralogical analyses of meteorites and lunar and terrestrial samples. Joined by the common belief that the complicated events leading to the present structure of the solar system can be understood only by an integrated chemical-physical approach, we have established a collaboration at the University of California, San Diego (UCSD), in La Jolla, during the last seven years. Our work, together with that of many colleagues in La Jolla, Stockholm, and elsewhere, has resulted in a series of papers describing the general principles of our joint approach, experimental results, and model approximations for some of the most important processes.

The present volume is a summary of our results, which we have tried to present in such a form as to make the physics understandable to chemists and the chemistry understandable to physicists. Our primary concern has been to establish general constraints on applicable models. Hence we have avoided complex mathematical treatment in cases where approximations are sufficient to clarify the general character of the processes.

The work was made possible by grants from the Planetology Program Office and the Lunar and Planetary Program Division, Office of Space Science, National Aeronautics and Space Administration Headquarters. Their longstanding help and encouragement particularly that of Steven E. Dwornik and Robert P. Bryson have been of crucial importance, and we are grateful also to Maurice Dubin for support. Our thanks are also extended to Homer E. Newell, John Pomeroy, Ernst Stuhlinger, and Dan M. Herman for their continuing active interest in this undertaking. In view of NASA's association through the years with the preparation of this [iv] study, we are particularly gratified to have it published (at the initiative of Steven E. Dwornik) as a NASA Special Publication.

The molding of the material into an organized and critically edited form is due to the dedicated and competent effort of Dawn S. Rawls. We also owe much gratitude to a number of our colleagues who have contributed in many ways to this work, particularly Bibhas R. De, Wing-Huen Ip, and Asoka Mendis at UCSD in La Jolla, and Nicolai Herlofson, Bo Lehnert, Carl-Gunne Fälthammar, Lars Danielsson, and Lennart Lindberg at the Royal Institute of Technology in Stockholm. Continual encouragement and advice from Professors Henry G. Booker, James R. Arnold, and William B. Thompson at UCSD have also been of importance in our work.