The idea of a symposium devoted to the contemporary knowledge of the world of Copernicus - the planetary system - to commemorate the 500th anniversary of his birth, came during the XIV General Assembly of IAU in Brighton. The Executive Committee has approved it in the program of the Extraordinary (Copernicus) General Assembly ofIAU in Poland in 1973. The IAU Symposium No 65 (Copernicus Symposium IV) on the 'Exploration of the Planetary System' was held in Copernicus' native town - Torun, Poland, from 5th to 8th September, 1973 under the auspices of Commissions 16 (Physical Study of Planets and Satellites) and 40 (Radio-astronomy) and the co-sponsorship of COSPAR. There were about 140 invited participants from 29 countries and about the same num­ ber of other participants to the Extraordinary General Assembly of IAU who came to Torun to attend the sessions of this symposium. Special funds of the Polish Acade­ my of Sciences made possible the participation of several young astronomers in this meeting. We are very grateful to Professor P. Swings, the Director of the Astrophysical Institute of the University of Liege, Belgium, for accepting the task of chairing this symposium. His expert and enthusiastic guidance helped us constantly in the prepara­ tion. The efforts of the Members of the Scientific Organizing Committee are also very much appreciated. Special thanks are due to Professors A. Dollfus and T. Owen.

Inhalt

I / Origin and General Physics of the Planetary System.- Planetary Formation.- Status of Molecular Opacities of Interest in the Modeling of a Proto-Solar Nebula.- On the Growth Mechanism of Grains in a Primordial Stage of the Solar Nebula.- The Escape of Planetary Atmospheres.- Modern Research in High Resolution Infrared Spectroscopy and Its Importance to Planetary Physics.- Optical Properties of Particles in Planetary Atmospheres: Laboratory Studies.- First Results of the Soviet-Polish Space Experiment 'Intercosmos-Kopernik 500'.- II / Terrestrial Planets.- Infrared Spectra of Venus.- Radio Interferometry of Venus at Short Wavelengths.- Profondeur de pénétration et formation des raies dans une atmosphère diffusante.- Etude théorique de la répartition de luminance sur le disque de Venus.- Numerical Modelling of the Reflection Spectrum of Venus in the Visual and Near Infrared Ranges.- Interpretation of the Illumination Measurements by the Automatic Interplanetary Station 'Venera 8'.- Nature of the Venus Clouds as Derived from Their Polarization.- Water Vapor in Venus Determined by Airborne Observations of the 8200 Å Band.- Ground-Based Observations of Mars and Venus Water Vapor during 1972 and 1973.- Observations of O2, H2O and HD in Planetary Atmospheres.- The Spectrum of Mars in the Region 1800-3200 cm?1.- Results of Current Mars Studies at the IAU Planetary Research Center.- UBV Photometry of Mars.- Photometric Data from Some Photographs of Mars Obtained with the Automatic Interplanetary Station 'Mars 3'.- Results from the Infrared Spectroscopy Experiment on Mariner 9.- Radio Occultation Exploration of Mars.- Mars: Local Structure of Dust Storms.- III / Outer Planets and Their Satellites.- The Hydrogen to Helium Mixing Ratio in the Giant Planets.- On the Equation of State of Hydrogen and Its Use in Models of Major Planets.- The Influence of the Surface Boundary Layer on Evolutionary Models of Jupiter.- Observations of Spatial and Temporal Variations of the Jovian H2 Quadrupole Lines.- TDIA Satellite Spectroscopic Observations of Jupiter in the Ultraviolet.- New Infrared Spectra of the Jovian Planets: Study of Jupiter and Saturn in the 3v3 Methane Band by Fourier Transform Spectroscopy.- On the Microwave Spectrum of Methane in the Atmospheres of the Outer Planets.- Jupiter's Microwave Spectrum: Implications for the Upper Atmosphere.- Jupiter's Radiation Belts and Upper Atmosphere.- Analysis of Spectroscopic Observations of Jupiter and the Variability of the Structure of the Visible Clouds.- Motions in Jupiter's Atmosphere.- Results of the Beta Scorpii Occultation by Jupiter on May 13, 1971.- Atmospheric Properties of Jupiter Determined from Galilean Satellite Eclipse Light Curves.- Millisecond Polarized Pulses in Decametre-Wave Radiation from Jupiter and Sun.- The Atmosphere of Saturn.- Models of Saturn's Rings which satisfy the Optical Observations.- A Study of the Outermost Ring of Saturn.- Theoretical Studies of an Atmosphere Around Saturn's Rings.- The Saturnian 'Gas-Doughnut' Hypothesis.- Observational Constraints on Model Atmospheres for Uranus and Neptune.- Neptune: Observations of the H2 Quadrupole Lines in the (4-0) Band.- La rotation, la cartographie et la photométrie des satellites de Jupiter.- Optical Line Emission from Io.- Relation Between Light Variations of Solar System Satellites and Their Interaction with Interplanetary Medium.- IV / Future Explorations of the Solar System.- Spectroscopic Observations of Venus.- Photopolarimetry of Planets.- Rationale for NASA Planetary Exploration Program.- Concluding Remarks.- Chairman's Closing Remarks.- Index of Authors.