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."

This Symposium was held at Surfer's Paradise, Queensland, Australia, from 7 to 11 September 1973. The Organizing Committee, chaired by J. P. Wild, consisted of A. Boischot, A. Bruzek, J. T. Jefferies, G. Newkirk, T. Takakura, and V. V. Zhelez nyakov. We are indebted to the Local Organizing Commettee, chaired by S. F. Smerd and including R. G. Giovanelli, R. E. Loughhead, N. G. Seddon, K. V. Sheridan, and J. P. Wild, for advice in preparing this volume as well as for the smooth arrangement of the sessions. In addition, the session chairmen and reporters are to be thanked for their assistance in preparing the recorded discussions. It is a pleasure to thank Mrs R. Toevs and Mr A. Csoeke-Poeckh of High Altitude Observatory for assistance in editing these Proceedings. The financial aid for the Symposium afforded by the International Astronomical Union, the Ian Potter Foundation of Melbourne, and the Sunshine Foundation of Melboume, as well as generous assistance of the CSIRO Divisions of Physics and Radiophysics is gratefully acknowledged. That the solar corona is not a quiescent plasma was first fully appreciated through the discovery of solar radio bursts thirty years ago. Since that time intensive re search has uncovered a vast variety of coronal disturbances and revised our con cept of this region of the solar atmosphere to that of a dynamic medium undergoing continuous expansion, constantly evolving under the influence of underlying photo spheric activity, and frequently traversed by transient phenomena.

The IAU Symposium No. 62, 'The Stability of the Solar System and of Small Stellar Systems' was held in Warsaw in Poland during the Extraordinary General Assembly of the IAU in commemoration of the SOOth anniversary of the birth of Nicolaus Copernicus. The Symposium was sponsored by Commission 7 (Celestial Mechanics) and cosponsored by Commissions 4 (Ephemerides) and 37 (Star Clusters and Asso- ciations) of the IAU and by IUTAM. The Organizing Committee included Y. Kozai (Chairman), J. A. Agekjan, A. Deprit, G. N. Duboshin, S. G\lska (Local represen- tative), M. Henon, B. Morando and C. Parkes (IUTAM representative). The Symposium was supported financially by the IA U, the IUT AM and the Polish Academy of Sciences. Y. KOZAI Chairman of the Organizing Committee STABILITY THEORY IN CELESTIAL MECHANICS J MOSER Courant Institute of Mathematical ScIences, New York University, New York, N. Y. 10012, U.S.A. Abstract, This expository lecture surveys recent progress of the stability theory in Celestial Mechanics with emphasis on the analytical problems. In particular, the old question of convergence of perturbation series are discussed and positive results obtained, in the light of the work by Kolmogorov Arnold and Moser. For the three body problem, classes of quasi-periodic solutions and doubly asymptotic (or homo- clinic) orbits are discussed.

Over the past two decades auroral science has developed from a somewhat mysterious and imprecise specialty into a discipline central in the study of the ionosphere and magnetosphere. The investigation of aurora unites scientists with very different backgrounds and interests so that it is difficult to write a self-contained account of the field in a book of reasonable length. In this work I have attempted to include those aspects of theory which I have found valuable in predicting the effects on the atmosphere of auroral particle precipitation. In addition I have attempted to describe the techniques of observation with particular emphasis on optical methods which have been useful. While the aeronomy of aurora has been regarded as central, the mechanisms by which particles are accelerated and precipitated into the atmosphere is of no less interest. This aspect of the subject has however been treated in a briefer fashion since it is a part of the immense and rapidly developing field of magnetospheric science. Generally I have attempted to provide a coherent introduction to auroral science with an emphasis on relatively simple physical interpretations and models. References are given to enable the reader to find more extensive or rigorous discussions of particular topics. A fairly complete, quantitative atlas of the auroral spectrum is included.

It was about fourteen years ago that some of us became intrigued with the idea of searching the sky for X-ray and gamma-ray sources other than the Sun, the only celestial emitter of high-energy photons known at that time. It was, of course, clear that an effort in this direction would not have been successful unless there occurred, somewhere in space, processes capable of producing high-energy photons much more efficiently than the processes responsible for the radiative emission of the Sun or of ordinary stars. The possible existence of such processes became the subject of much study and discussion. As an important part of this activity, I wish to recall a one-day conference on X-ray astronomy held at the Smithsonian Astrophysical Observatory in 1960. The theoretical predictions did not provide much encouragement. While several 'unusual' celestial objects were pin-pointed as possible, or even likely, sources of X-rays, it did not look as if any of them would be strong enough to be observable with instru mentation not too far beyond the state of the art. Fortunately, we did not allow our selves to be dissuaded. As far as I am personally concerned, I must admit that my main motivation for pressing forward was a deep-seated faith in the boundless re sourcefulness of nature, which so often leaves the most daring imagination of man far behind."

The aim of the present book will be to summarize the results of the space exploration of the Moon in the past fifteen years -culminating in the manned Apollo missions of 1969-1972 -on the background of our previous acquaintance with our satellite made in the past by astronomical observations at a distance. Astronomy is one of the oldest branches of science conceived by the inquisitive human mind; though until quite recently it had been debarred from the status of a genuine experimental science by the remoteness of the objects of its study. With the sole exception of meteoritic matter which occasionally finds its way into our labora tories, all celestial bodies could be investigated only at a distance: namely, from the effects of attraction exerted by their mass, or from the ciphered messages of their light carried by nimble-footed photons across the intervening gaps of space. A dramatic emergence oflong-range spacecraft -capable of carrying men with their instruments not only outside the confines of our atmosphere, but to the actual surface of our nearest celestial neighbour - has since 1957 thoroughly changed this time honoured picture. In particular (as we shall detail in Chapter 1 of this book) space astronomy ofthe Moon is barely 15 years old. But relative infant as it is by age, it has already provided us with such a tremendous amount of new and previously inacces sible scientific data as to virtually revolutionalize our subject."

The devotion of an IA U symposium entirely to the topic of chromo spheric fine structure at a time when models of the spherically symmetric chromosphere are still evolving constitutes a valid recognition of the growing feeling among solar astron omers that the chromosphere cannot be understood independently of its discrete structural features. Network structure, which seemingly borders the photospheric supergranule cells, persists intact throughout the chromosphere and most of the chromosphere-corona transition region. The network is the locus of the bright coarse mottles, and the spicule bushes and is the terminus for one end of the quiet chromo spheric fibrils as well. Additionally, it is the locus of most of the magnetic flux of the quiet chromosphere. It is not surprising, therefore, that current studies of the chromosphere tend to center around efforts to better describe the network phenom ena and to ascertain the physical properties of the network features. Clearly, the supergranule cells and associated network structures constitute a fundamental and singularly important feature of solar structure in the boundary layers. Just as it is now clear that much of the chromo spheric fine structure is associated with the network bordering supergranule cells, it seems equally clear that structural features are almost universally associated with both fluid flow and magnetic geometry. Indeed, many observers claim that the brightness features faithfully map the mag netic lines offorce while still others claim that associated with each class of brightness feature there is a more or less unique fluid flow."

o beaute sans seconde SeuIe sembIabIe Ii toi SOLEIL pour tout Ie monde ... JEAN-FRANc;OIS SARASIN (1615-1654) The last decade has seen the publication of monographs covering most areas of solar activity: flares (Smith and Smith, 1963), sunspots (Bray and Loughhead, 1964) and the corona (Billings, 1966). Consequently, of all the major manifestations of solar activity only prominences are without a comprehensive and unified treatment in the current literature. The present book is written in an attempt to remedy this situation, and to furnish an account of some of the most spectacular and most beautiful aspects of solar activity. Our ultimate aim is an understanding of the physical processes involved. I hope that this book may provide if only a small step toward this goal. After an historical introduction and some general definitions Chapter I proceeds with an account of several classification schemes for prominences. Most of the observational material is presented in Chapter II and forms the basis on which different models of prominences are built in Chapter III. Chapters IV and V give most of the physics of prominences, treating, as they do, the formation and stability of these objects. The interaction of prominences with other manifestations of solar activity is the subject of Chapter VI, and the final Chapter VII considers prominences in the larger context: as an integral part of the corona.

Marvel at the wonders of the Universe, from stars and planets to black holes and nebulae, in this exploration of our Solar System and beyond. Universe opens with a look at astronomy and the history of the Universe, using 3D artworks to provide a comprehensive grounding in the fundamental concepts of astronomy, including the basic techniques of practical astronomy. The core of the book is a tour of the cosmos covering the Solar System, the Milky Way, and galaxies beyond our own. Explanatory pages introduce different celestial phenomena, such as galaxies, and are followed by catalogues that profile the most interesting and important examples. A comprehensive star atlas completes the picture, with entries on each of the 88 constellations and a monthly sky guide showing the night sky as it appears throughout the year as viewed from both the northern and southern hemispheres.

Full of personal insights and accounts of the long journey to getting a man on the moon, Missions to the Moon is the perfect companion for anyone with a love of space travel, the moon landings, or NASA, CNSA, RFSA, and the rest of the world's space programs. With dozens of stunning photographs and fascinating memorabilia - such as Apollo 11 Mission Reports and Flight Director's Logs - track the birth of the space race and Yuri Gagarin's first space flight, to the many successes and failures of the Apollo mission, all the way to that boots-on-the-ground moment we have come to know so well. Uniquely complemented by ground-breaking digital technology you can become fully immersed in this interactive story of mankind's ongoing journey into the final frontier.

This book provides readers with an understanding of the basic physics and mathematics that governs our solar system. It explores the mechanics of our Sun and planets; their orbits, tides, eclipses and many other fascinating phenomena. This book is a valuable resource for undergraduate students studying astronomy and should be used in conjunction with other introductory astronomy textbooks in the field to provide additional learning opportunities. Features: Written in an engaging and approachable manner, with fully explained mathematics and physics concepts Suitable as a companion to all introductory astronomy textbooks Accessible to a general audience

In this volume of essays, the top experts and major players behind the United States's recently renewed push to the moon fuel a growing debate over lunar exploration. The announcement in 2004 that the U.S. would be revamping its moon program inspired both excitement about the possibilities and concern over cost and safety issues. This book takes the controversy out of the realm of pure science and into the mainstream of national debate. Lunar experts Alan Binder, Andy Chaikin, Yoji Kondo, Courtney Stadd, Frank White, and many others weigh in on the case for a return, point out the best way to do it, and speculate on what could be done with this newly obtained real estate. The essays are accompanied by illustrations of what life on the moon might look like. Contributions come from different perspectives and styles, offering a broad take on the very real possibility that humans will again walk-- and work, live, and play-- on the lunar landscape. From telescopes and tourism, to training for Mars, to building a new branch of humanity and saving the Earth, this compendium makes the case for sending people back to the moon.

Celebrating the centenary of George Ellery Hale's discovery of magnetic fields in sunspots, IAU Symposium 273 reviews the recent advances made in the fields of solar and stellar magnetism. Sunspots are responsible for the time-varying properties of the Sun, including the solar irradiance. Combined study of the spots on the Sun and on other stars provides a greater understanding of sunspot formation and behaviour on a long-term basis. On the other hand, stellar observations can be best understood by using detailed properties of the Sun as a reference point. This volume contains reviews and research articles from solar and stellar astronomers on the recent findings of solar and stellar magnetism using observational, theoretical and simulation studies of the Sun and the stars to approach the subject in a unified manner. Its findings are useful to advanced students and researchers in solar and stellar astronomy.

Illustrated with breathtaking images of the Solar System and of the Universe around it, this book explores how the discoveries within the Solar System and of exoplanets far beyond it come together to help us understand the habitability of Earth, and how these findings guide the search for exoplanets that could support life. The author highlights how, within two decades of the discovery of the first planets outside the Solar System in the 1990s, scientists concluded that planets are so common that most stars are orbited by them. The lives of exoplanets and their stars, as of our Solar System and its Sun, are inextricably interwoven. Stars are the seeds around which planets form, and they provide light and warmth for as long as they shine. At the end of their lives, stars expel massive amounts of newly forged elements into deep space, and that ejected material is incorporated into subsequent generations of planets. How do we learn about these distant worlds? What does the exploration of other planets tell us about Earth? Can we find out what the distant future may have in store for us? What do we know about exoworlds and starbirth, and where do migrating hot Jupiters, polluted white dwarfs, and free-roaming nomad planets fit in? And what does all that have to do with the habitability of Earth, the possibility of finding extraterrestrial life, and the operation of the globe-spanning network of the sciences?

This book provides readers with an understanding of the basic physics and mathematics that governs our solar system. It explores the mechanics of our Sun and planets; their orbits, tides, eclipses and many other fascinating phenomena. This book is a valuable resource for undergraduate students studying astronomy and should be used in conjunction with other introductory astronomy textbooks in the field to provide additional learning opportunities. Features: Written in an engaging and approachable manner, with fully explained mathematics and physics concepts Suitable as a companion to all introductory astronomy textbooks Accessible to a general audience

This book presents pioneering work on a critical observational test of the planet formation theory based on the theoretical study of the water snowline, beyond which water takes the form of ice, in the protoplanetary disks - the place where planets are formed. Since the water snowline is thought to divide the regions of rocky and gas-giant planet formation, the location of the snowline is essential for the planet formation process. The book proposes a novel method to locate the snowlines using high-dispersion spectroscopic observations of water vapor lines, which is based on in sophisticated chemical modeling and line radiative transfer calculations. The author obtained the water vapor distribution in the disks using the chemical reaction network, which includes photoreactions and gas-grain interactions. The simulated transition lines of water vapor in the disks demonstrate that relatively weak transition lines with moderate excitation energies are the best tracers of water snowline. Furthermore, the author observed submillimeter lines of water vapor in a disk using ALMA (Atacama Large Millimeter/submillimeter Array) to obtain the upper limit of the line fluxes with the highest sensitivity to date. These unprecedented findings are important in locating the snowlines in the disks, and the method goes a long way toward achieving a comprehensive understanding of the planet formation processes as well as of the origin of water on rocky planets, including our Earth, based on future observations using ALMA and SPICA (Space Infrared Telescope for Cosmology and Astrophysics).

Many astrophysical bodies produce winds, jets or explosions, which blow spectacular bubbles. From a nonmathematical, unifying perspective, based on the understanding of bubbles, the authors address many of the most exciting topics in modern astrophysics including supernovae, the production of structure in the Early Universe, the environments of supermassive black holes and gamma-ray bursts.

This book introduces the reader to all the basic physical building blocks of climate needed to understand the present and past climate of Earth, the climates of Solar System planets, and the climates of extrasolar planets. These building blocks include thermodynamics, infrared radiative transfer, scattering, surface heat transfer and various processes governing the evolution of atmospheric composition. Nearly four hundred problems are supplied to help consolidate the reader's understanding, and to lead the reader towards original research on planetary climate. This textbook is invaluable for advanced undergraduate or beginning graduate students in atmospheric science, Earth and planetary science, astrobiology, and physics. It also provides a superb reference text for researchers in these subjects, and is very suitable for academic researchers trained in physics or chemistry who wish to rapidly gain enough background to participate in the excitement of the new research opportunities opening in planetary climate.