P. J. MESSAGE University of Liverpool The papers which comprise this volume were presented at Colloquium No. 41 of the International Astronimical Union, which was held in Cambridge, England, from the 17th to the 19th of August, 1976, and had as its subject 'Dynamics of Planets and Satellites and Theories of their Motion'. The Colloquium was held just prior to the XVIth General Assembly of the Union (which was held from 24th August to 2nd September, in Grenoble, France) to provide an opportunity for the presentation of research papers on a number of active and lively branches of Celestial Mechanics to a gathering of experts in the field, and for the stimulus of discussion of research problems of interest to participants. A number of papers testify to the progress being made in General Planetary Theory, the theories of motion of the minor planets, the Moon, and the satellites of Jupiter and Saturn, and to significant advances in both the general and restricted gravitational problems of three bodies. The Organizing Committee of the Colloquium was comprised of J. Chapront, R. L. Duncombe, J. Hadjidemetriou, Y. Kozai, B. Morando, J. Schubart, V. Szebehely, and P. J. Message (Chairman). The local Organizer was D. C. Heggie, to whose tireless efforts the success of the arrangements is due. IX LIST OF PARTICIPANTS N. Abu-el-Ata, Bureau des Longitudes, 77 Avenue Denfert Rochereau, 75014 Paris, France K. Aksnes, Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, U. S. A.

P. J. MESSAGE University of Liverpool The papers which comprise this volume were presented at Colloquium No. 41 of the International Astronimical Union, which was held in Cambridge, England, from the 17th to the 19th of August, 1976, and had as its subject 'Dynamics of Planets and Satellites and Theories of their Motion'. The Colloquium was held just prior to the XVIth General Assembly of the Union (which was held from 24th August to 2nd September, in Grenoble, France) to provide an opportunity for the presentation of research papers on a number of active and lively branches of Celestial Mechanics to a gathering of experts in the field, and for the stimulus of discussion of research problems of interest to participants. A number of papers testify to the progress being made in General Planetary Theory, the theories of motion of the minor planets, the Moon, and the satellites of Jupiter and Saturn, and to significant advances in both the general and restricted gravitational problems of three bodies. The Organizing Committee of the Colloquium was comprised of J. Chapront, R. L. Duncombe, J. Hadjidemetriou, Y. Kozai, B. Morando, J. Schubart, V. Szebehely, and P. J. Message (Chairman). The local Organizer was D. C. Heggie, to whose tireless efforts the success of the arrangements is due. IX LIST OF PARTICIPANTS N. Abu-el-Ata, Bureau des Longitudes, 77 Avenue Denfert Rochereau, 75014 Paris, France K. Aksnes, Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, U. S. A.

The Dynamics of Natural Satellites of the Planets is an accessible reference for understanding the celestial mechanics of planetary moons through the lens of both theory and observation. Based on decades of research by the author, the book utilizes state-of-the-art observations of the natural satellites in the solar system to establish models, measurements and calculations to better understand the theory of the satellite movement and dynamics. It presents an extensive set of study methods and results on the motion of natural satellites of the planets and includes reviews and references to related publication for further explanation. By relating observations to numerical theory, the book serves as a quick and comprehensive reference for applying the theory of orbital dynamics to observational data on orbits and physical properties of the natural satellites in order to formulate state-of-the-art explanations and models, particularly for determining the parameters of satellite motion. Combines astronomy and celestial mechanics, providing astrometric data from observations to inform methods and models for predicting natural satellite dynamics Includes both theory and observation in one place and presents new models based on observations Organized into small sections, each providing specific measurements, calculations or models, making it a quick and comprehensive reference

Orbital motion is a vital subject which has engaged the greatest minds in mathematics and physics from Kepler to Einstein. It has gained in importance in the space age and touches every scientist in any field of space science. Still, there is almost a total dearth of books in this important field at the elementary and intermediate levels — at best a chapter in an undergraduate or graduate mechanics course.This book addresses that need, beginning with Kepler's laws of planetary motion followed by Newton's law of gravitation. Average and extremum values of dynamical variables are treated and the central force problem is formally discussed. The planetary problem in Cartesian and complex coordinates is tackled and examples of Keplerian motion in the solar system are also considered. The final part of the book is devoted to the motion of artificial Earth satellites and the modifications of their orbits by perturbing forces of various kinds.

In their search for solutions to problems concerning the dynamics of the Earth as a self-gravitating body, the authors have applied the fundamentals found in their book “Jacobi Dynamics” (1987, Reidel). First, satellite observations have shown that the Earth does not remain in hydrostatic equilibrium, which forms the physical basis of modern geodynamics. Secondly, satellite data have established a relationship between the planet’s polar moment of inertia and the potential of the Earth’s outer force field, which proves the most basic point of Jacobi dynamics. This allowed the authors to revise their derivation of the classical virial theorem, introducing the concept of a volumetric force and volumetric moment, and so to obtain a generalized virial theorem in the form of Jacobi’s equation. The main dynamical effects are: the kinetic energy of oscillation of the interacting particles, which explains the physical meaning and nature of gravitational forces; separation of shells of a self-gravitating body with respect to its mass density; differences in angular velocities of the shell’s rotation; continuity in variance of the potential of the outer gravitational force field, together with reductions in the envelope of the interacting masses (volumetric center of gravity); the nature of Earth, Moon and satellite precession; the nature and generating mechanism of the planet’s electromagnetic field; the common nature of gravitational and electromagnetic energy, and other related issues. The work is a logical continuation of the book "Jacobi Dynamics" and is intended for researchers, teachers and students engaged in theoretical and experimental research in various branches of astronomy, geophysics, planetology and cosmogony, and for students of celestial, statistical, quantum and relativistic mechanics and hydrodynamics.