Laser physics and nonlinear optics are fields which have been intimately con nected from their beginning. Nonlinear optical effects such as second-har monic generation fulfil vital functions in many laser systems. Conversely advances in laser development quickly lead to progress in nonlinear optics. Of particular importance has been the development of tunable visible and uv lasers. With the ability to tune the laser frequency into close resonance with atomic transition frequencies, one can produce a large resonance en hancement of the nonlinearity. This permits the observation of a great var iety of nonlinear optical processes in dilute media such as atomic vapours. In recent years much of the research effort in nonlinear optics has been directed towards the use of such media, and it is this area which forms the subject of the present book. We review a wide range of nonlinear optical processes in atomic vapours, molecular gases and cryogenic liquids. At the same time we have tried to treat the subject in sufficient depth to be useful to research workers in the field. To achieve this, a measure of selectivity has been introduced by emphasising those nonlinear processes which are seen to have applications as sources of tunable coherent radiation. Thus we have not discussed in any detail those nonlinear processes whose main applications are in spec troscopy, such as Doppler-free two-photon absorption."

Although recent works on Galileo's trial have reached new heights of erudition, documentation, and sophistication, they often exhibit inflated complexities, neglect 400 years of historiography, or make little effort to learn from Galileo. This book strives to avoid such lacunae by judiciously comparing and contrasting the two Galileo affairs, that is, the original controversy over the earth's motion ending with his condemnation by the Inquisition in 1633, and the subsequent controversy over the rightness of that condemnation continuing to our day. The book argues that the Copernican Revolution required that the hypothesis of the earth's motion be not only constructively supported with new reasons and evidence, but also critically defended from numerous old and new objections. This defense in turn required not only the destructive refutation, but also the appreciative understanding of those objections in all their strength. A major Galilean accomplishment was to elaborate such a reasoned, critical, and fair-minded defense of Copernicanism. Galileo's trial can be interpreted as a series of ecclesiastic attempts to stop him from so defending Copernicus. And an essential thread of the subsequent controversy has been the emergence of many arguments claiming that his condemnation was right, as well as defenses of Galileo from such criticisms. The book's particular yet overarching thesis is that today the proper defense of Galileo can and should have the reasoned, critical, and fair-minded character which his own defense of Copernicus had.

These words are written on the SOOth anniversary of Columbus' discovery of the New World. Surely the deep-space exploration of other worlds in our Solar System over the past few decades is an event of similar magnitude. Man has traveled far enough to see Spaceship Earth suspended alone in black space. And he has voyaged even farther to marvel at the crescent Earth rising over the Moon's cratered terrain. Instrumented spacecraft have toured the entire Solar System even beyond the ninth planet Pluto. This work of science Morphology of the Rocky Members of the Solar System is an inquiry about our extended home. As with the Darwinian and Copernican paradigms, the nature of our planetary system, as the extended world around us, has great significance for those who ponder the human condition. The deep-space views of our Planet Ocean with its sweeping clouds, and moving oceans and creeping continents must rank as the greatest photograph ever taken. Viewing Spaceship Earth hanging in the vast void is an almost frightening experience. We are so alone! It is easy to understand why so many are attracted to a simpler account of origins, like the allegorical tale of creation written in heroic style (but eschewing math, maps, figures, tables, references, and evidence) in the first eleven chapters of Genesis. This treatise examines the morphology of the six rocky planets and their 27 satellites from a broad perspective.

th The 29 International Conference was held as the first one of the millennium at its Fort Lauderdale venue. These conferences began, with High Energy Physics being the main topic, by introducing gradually cosmology into its programs. These proceedings of the 2000 conference reflect the variety of topics and ideas discussed. Our future conferences will be designed somewhat akin to the early Coral Gables Conferences where we shall seek some convergence of ideas. For this reason various committees have been formed from among the participating physicists. The committees and their memberships are listed in these proceedings. We further decided for the first time to include some graduate student participants in our future meetings for which also a committee has already been established. The topics will demonstrate a more activist structure of the Coral Gables Conferences, for example the duality of the gravitational forces and expansion of the universe will be discussed from this point of view since it conveys a convergence to the ideas of quintessence versus the ordinary theory, which are considered as the cause of the expansion of the universe. We further wish to announce that the future conferences will assume a collective organization where several committees as listed in these proceedings will have their input into the conference. We have now introduced new topics and ideas, which referred especially to the attractive and repulsive nature of the gravitational force. These proceedings of the conference contain a variety of topics and ideas.

Nobel Symposium No 31 on The Impact of Space Science on Man kind was held at Spatind, Norway, September 7 - 12, 1975. Twenty seven leading experts from the United States, the U. S. S. R. and Western Europe attended the Symposium. Four main subjects were discussed: The Impact of Space Science, introduced by Profe. ssor Reimar Lust; The Impact of Space Communica tion, ihtroduced by Dr Joseph Charyk; The Impact of Earth Resources Exploration from Space, introduced by Dr William Nordberg; and The Impact of Space Assisted Meteorology, introduced by Dr Robert M White. This book contains edited summaries of the papers presented at the Symposium and summaries of the discussions. The Symposium was financed by the Nobel Foundation through grants from the Tercentenary Foundation of the Bank of Sweden and organized by a special committee appointed by the Norwegian Nobel Institute. Tim Greve Finn Lied Erik Tandberg vii CONTENTS The Impact of Space Science 1 R. Lust The Impact of Space Science on Mankind (Discussion) 13 T. R. Larsen (ed. ) Satellite Communications 25 J. V. Charyk The Impact of Space Communication (Discussion) 57 G. Rosenberg (ed. ) The Impact of Earth Resources Exploration from Space 67 W. Nordberg The Impact of Earth Resources Exploration from Space 79 (Discussion) E. Tandberg (ed. ) The Environmental Satellite: What It Means for Man 91 R. M. White The Impact of Space Assisted Meteorology (Discussion) 111 E. Tandberg (ed.

Sects. 12, 13. 89 sequence and that subgiant and fainter stars in globular clusters have ultraviolet excesses. When dealing with stars whose physical properties are imperfectly under stood, such as in globular cluster stars, we cannot rely too heavily on the empiri cal calibration by the kinds of stars used to define Fig. 5, to determine their true, unreddened U-B, B-V curve. But if by a combination of arguments, principally the reddening in the region of the stars we do known about, we can assign a fairly probable unreddened U-B, B-V curve to a group of stars about which we know little, the argument may be turned around. In this case some information may be gained about the energy envelope of the stars by examining the differences between the normal two-color index curves for the unknown group of stars compared to the known. In general there seem to be two possible causes for different stars defining different normal sequences in the U-B, B-V plane. One, the relative energy distribution in the continuum in the U, B and V photometry bands are different. An example of this is the effect of the Balmer depression in supergiants. This, of course, requires deviation from black body radiation curves for one or both groups of stars. This cause seems to be the dominant effect for very blue, hot stars where the depression of the continuum by absorption lines is at a minimum."

"Dark matter" was first introduced by Zwicky in 1933 to resolve a discrepancy be tween the dynamical and luminous masses of the Coma cluster. In spite of tremen dous developments in observations and various theoretical attempts, the problem of dark matter has not been resolved but has rather deepened in mystery. Though it is now certain that dark matter constitutes a dominant part of the matter in the universe, its distribution and accurate abundance are not known well. Though many people believe that it consists of non-baryonic matter, no one can reject the bary onic candidate for sure. Though it may have surely played important roles in the formation of galaxies and their large-scale distribution, there exists no theory which is consistent with all the observational facts. Resolution of this frustrating situation is one of the urgent problems in astronomy, cosmology and particle physics. One obstacle for this is the diverse nature of the problem. More researchers are therefore invited to participate in this rich field. This volume contains lectures presented at the third N ishinomiya-Yukawa Memo rial Symposium on "Dark Matter in the Universe" held on 10-11 November 1988, in Nishinomiya City. This symposium was intended to present an introduction of the dark matter problem to young newcomers, and physicists and astrophysicists who had not specialized in this field. These proceedings will provide them with a comprehensive and current survey of the problem."

Ram accelerators are among the most advanced tools for generating fluid dynamcis data in supersonic reacting systems. They require the combined action of combustion, wave systems and turbulence and are still a serious challenge for physicists and engineers. This book will serve as an introductionary textbook on ram accelerators and gives a thorough overview on research activities, performance modeling and high-pressure detonation dynamics.

Although the development of ideas about the motion and trajectory of comets has been investigated piecemeal, we lack a comprehensive and detailed survey of ph- ical theories of comets. The available works either illustrate relatively short periods in the history of physical cometology or portray a landscape view without adequate details. The present study is an attempt to review - with more details - the major physical theories of comets in the past two millennia, from Aristotle to Whipple. My research, however, did not begin with antiquity. The basic question from which this project originated was a simple inquiry about the cosmic identity of comets at the dawn of the astronomical revolution: how did natural philosophers and astronomers define the nature and place of a new category of celestial objects - comets - after Brahe's estimation of cometary distances? It was from this turning point in the history of cometary theories that I expanded my studies in both the pre-modern and modern eras. A study starting merely from Brahe and ending with Newton, without covering classical and medieval thought about comets, would be incomplete and leave the fascinating achievements of post-Newtonian cometology unexplored.

Topological defects have recently become of great interest in condensed matter physics, particle physics and cosmology. They are the unavoidable remnants of many symmetry breaking phase transitions. Topological defects can play an important role in describing the properties of many condensed matter systems (e.g. superfluids and superconduc tors); they can catalyze many unusual effects in particle physics models and they may be responsible for seeding the density perturbations in the early Universe which de velop into galaxies and the large-scale structure of the Universe. Topological defects are also of great interest in mathematics as nontrivial solutions of nonlinear differential equations stabilized by topological effects. The purpose of the Advanced Study Institute "Formation and Interactions of Topo logical Defects" was to bring together students and practitioners in condensed matter physics, particle physics and cosmology, to give a detailed exposition of the role of topo logical defects in these fields; to explore similarities and differences in the approaches; and to provide a common basis for discussion and future collaborative research on common problems.

During the past few decades we have witnessed at least two major innovations in science which have had substantial impact on technology as well as science itself, pervasive enough to modify many facets of our daily lives. We refer, of course, to the tran sistor and the laser. It is striking that now with the advent of optical bistability we may have opened the door to another such field, which combines these two aspects (transistor and laser) and has the possibility for important device applications as well as providing a unique window into the as yet not thoroughly explored frontiers of nonequilibrium statistical physics. This has prompted us to organize an international conference on the subject of optical bistability to provide an adequate means for assessing the current state of the art of this important field and to stimulate further significant developments by means of in tense technical exchange and interaction among the leading scien tists in this subject area.

Since the 1970s symposia or colloquia devoted to recent research on close binaries have been held around the world almost annually. At meetings of the General Assembly of the International Astronomical Union this topic has also been discussed in detail at presentations in various commission meetings and also as invited talks by leading astronomers in the field. In recent years, fundamental changes have taken place in the study of close binaries due to the improvements in observational techniques, extension of observations from X-ray to radio regions of the electromagnetic spectrum, and advances in theoretical studies. For more than a decade, a group of astronomers at Ege University Observatory has been concentrating on active close binaries with particular emphasis on the behaviour of the light curves of chromospherically active systems. Thus, we decided to organize an international meeting in Western Anatolia, where this part of Turkey had been the cradle for great developments in science during antiquity. KUljadasi, located only minutes away from Ephesus, one of the seven wonders of the world, was selected to be the meeting site. Close binary systems constitute a very rich source of information about the physical properties of the component stars. Some systems are eclipsing variables, where periodic recurrences of eclipses are observed as comparatively brief decreases in the total brightness of the binary system. Precise methods of photometric observations make it possible to obtain the light variations of these systems because of eclipses and other phenomena.

The International Conference, Orbis Scientiae 1996, focused on the topics: The Neutrino Mass, Light Cone Quantization, Monopole Condensation, Dark Matter, and Gravitational Waves which we have adopted as the title of these proceedings. Was there any exciting news at the conference? Maybe, it depends on who answers the question. There was an almost unanimous agreement on the overall success of the conference as was evidenced by the fact that in the after-dinner remarks by one of us (BNK) the suggestion of organizing the conference on a biannual basis was presented but not accepted: the participants wanted the continuation of the tradition to convene annually. We shall, of course, comply. The expected observation of gravitational waves will constitute the most exciting vindication of Einstein's general relativity. This subject is attracting the attention of the experimentalists and theorists alike. We hope that by the first decade of the third millennium or earlier, gravitational waves will be detected, opening the way for a search for gravitons somewhere in the universe, presumably through the observations in the CMBR. The theoretical basis of the graviton search will take us to quantum gravity and eventually to the modification of general relativity to include the Planck scale behavior of gravity -at energies 19 of the order of 10 Ge V.

These proceedings are the result of a three-day meeting held in Oogliani (Italy), on October 2-4 2003, whose title was "VIrtual Astrophysical Jets 2003". Our goal in convening this meeting was to gather some of the scientists among the most active in the field of numerical simulations and modelling of astrophysi cal jets. For keeping the participants close to the "real world", we also invited a few observers to give up-to-date reviews outlining the state-of-the-art of jet observations. The principal aim of the meeting was thus to present and critically discuss the state-of-the-art numerical simulations, analytical models and laboratory ex periments for reproducing the main aspects of astrophysical jets and compar ing them with observations. The discussion has been focused on the following topics: * Observations and intepretions of jets from young stars and AGNs, comparisons of models with observations; * MHO accelerations of jets: steady self-similar models, MHO numerical simula tions of time-dependent accelerations mechanisms; * Jet stability and interaction with the ambient: formation of knots in YSO jets, jet survival to instabilities, deceleration of relativistic jets in FRI sources, simulations of jets-IGM interactions, jets propagation and galaxy formation; * Numerical codes and their validation: relativistic MHO codes, comparisons among different numerical schemes, jets in the laboratory and code validation. These topics have been discussed intensively during the meeting, and the out come of these discussions is presented in this volume. The contributions have been divided in five sections.

The physical processes driving the different manifestations of the phe nomenon of active galactic nuclei have been studied extensively during the last decade. A major obstacle in all attempts to understand the relevant pro cesses has always been the wide range of frequencies over which significant fractions of the total power are emitted. During the last decade, orbiting telescopes and instrumental improvements for ground-based instrumenta tion provided the means for major advancements on the observational side. The organizers felt that it was timely to organize a meeting to discuss the impact of this new situation on the understanding of the relevant physical processes. More then 400 astrophysicists were interested in participating in the meeting, in spite of the constraints on overseas travel which were imposed in early 1991. Unfortunately only 220 participants could be hosted by the Max-Planck-Haus, the site of the 1991 Heidelberg conference. The meet ing was organized by Sonderforschungsbereich 328 "Evolution of Galaxies". During 5 sessions, most of which lasted for one day each, 47 invited and con tributed talks and 150 poster papers were given, most, but not all, of which are included in these proceedings. With a few exceptions the order of the written texts follows that of the oral contributions during the meeting. The arrangement of posters into the five sections was not always unambiguous. We hope to have placed them in the most appropriate sections, in which they are listed in alphabetical order.

In the 18th century, purely scientific interests as well as the practical necessities of navigation motivated the development of new theories and techniques to accurately describe celestial and lunar motion. "Between Theory and Observations" presents a detailed and accurate account, not to be found elsewhere in the literature, of Tobias Mayer's important contributions to the study of lunar motion-including the creation of his famous set of lunar tables, which were the most accurate of their time.

Neutrinos play a fundamental role in the latest particle physics theories, such as Grand Unified Theories, theories of supersymmetry, and superstring theory. Their mass yields an important boundary condition for grand unification models. They are the best candidates for dark matter in the universe, and their mass could determine its large scale structure and evolution. Neutrinos probe the interior of collapsing stars, and understanding them may lead to a solution of the solar neutrino problem. In ten chapters written by experts in each of these fields this book gives a comprehensive presentation of our current knowledge of the neutrino, of its role in nuclear particle and astrophysics theories, and of ongoing experimental efforts to learn more about its own nature. Graduate students and researchers in these fields will find this book a reliable advanced text and source of reference.

After the launching of the first artificial satellites preceding interplanetary vehicles, celestial mechanics is no longer a science of interest confined to a small group of astronomers and mathematicians; it becomes a special engineering technique. I have tried to set this book in this new perspective, by severely limiting the choice of examples from classical celestial mechanics and by retaining only those useful in calculating the trajectory of a body in space. The main chapter in this book is the fifth, where a detailed solution is given of the problem of motion of an artificial satellite in the Earth's gravitational field, using the methods of Von Zeipel and of Brouwer. It is shown how Lagrange's equations can be applied to this problem. The first four chapters contain proofs of the main results useful for these two methods: the elliptical solution of the two-body problem and the basic algebra of celestial mechanics; some theorems of analytical mechanics; the Delaunay variables and the Lagrangian equations of variation of elements; the expansion of the disturbing function and the Bessel functions necessary for this expansion. The last two chapters are more descriptive in character. In them I have summarized briefly some of the classical theories of celestial mechanics, and have tried to show their distinctive characteristics without going into details.

The concept of infinity is one of the most important, and at the same time, one of the most mysterious concepts of science. Already in antiquity many philosophers and mathematicians pondered over its contradictory nature. In mathematics, the contradictions connected with infinity intensified after the creation, at the end of the 19th century, of the theory of infinite sets and the subsequent discovery, soon after, of paradoxes in this theory. At the time, many scientists ignored the paradoxes and used set theory extensively in their work, while others subjected set-theoretic methods in mathematics to harsh criticism. The debate intensified when a group of French mathematicians, who wrote under the pseudonym of Nicolas Bourbaki, tried to erect the whole edifice of mathematics on the single notion of a set. Some mathematicians greeted this attempt enthusiastically while others regarded it as an unnecessary formalization, an attempt to tear mathematics away from life-giving practical applications that sustain it. These differences notwithstanding, Bourbaki has had a significant influence on the evolution of mathematics in the twentieth century. In this book we try to tell the reader how the idea of the infinite arose and developed in physics and in mathematics, how the theory of infinite sets was constructed, what paradoxes it has led to, what significant efforts have been made to eliminate the resulting contradictions, and what routes scientists are trying to find that would provide a way out of the many difficulties.

The present NATO Advanced Study Institute held in CARGESE (Corsica) from Au- gust 8th to August 18th, 1989 was devoted to Hadronic Physics. We tried to give this school a key educational role in this new and rapidly developing interdisciplinary field. We hope that the combination of the lectures and the open atmosphere of scientific exchange and inquiry afforded by the Cargese format has provided a unique educational and scien- tific opportunity for students and has brought together all the relevant concepts and issues for frontier research in this field. We would like to express our gratitude to NATO for its generous financial support which made this Institute possible. We also wish to thank Dr. Luis V. Da Cunha, Director of the Scientific Affairs Division, for his valuable comments and advice. We acknowledge the support of the Institut de Physique Nucleaire et de Physique des Particules (France), the Commissariat a l'Energie Atomique (France), and the U.S. National Science Fundation, for the attribution of travel grants. Our special appreciation is due to Frederique Dykstra for her oustanding organiza- tional work throughout the preparation and duration of this conference It is also a pleasure to thank the Universite de Nice for making available the facilities of the Cargese Scientific Institute. The pictures of the lecturers included in the present volume were kindly provided by one of the participants, Dr.R.Janner.

The Ionospheric Institute of the National Observatory of Athens has had two interests in recent years: the study of the ionosphere and the study of the sun. In our previous Advanced Study Institutes in 1960, 1961, and 1962, we have em phasized the ionosphere. For the Advanced Study Institute of 1964, however, we invited Dr. Jules Aarons of the Air Force Cambridge Research Laboratories to collaborate in preparing and directing a program of studies of the sun, the moon, the planets, and the interplanetary medium. The lectures of this Advanced Study Institute form essentially an advanced course in radio astronomy. Without being a textbook on the matter, we feel that the present book can be considered as an excellent reference for those students starting their research work in the field of solar system radio astronomy. All lecturers tried to present their subjects in a simple form based upon their exten sive personal experience, but without emphasizing their personal research. We must recognize that it was an excellent achievement for them to keep their text exactly at the level indicated by the Program Director, and outlined by the gen eral program of Advanced Study Institutes of NATO. We are deeply grateful to all the invited scientists for their outstanding contributions in lecturing on their subjects in a clear and authoritative manner. The Scientific Affairs Division of NATO, in its aid to basic research, spon sors various programs. Among them is the Program of Advanced Study Institutes."

This book gathers the proceedings of a symposium on Dynamics of satellites which took place in Prague in May 1969 during the twelfth COSPAR meeting. This symposium was sponsored by the International Astronomical Union, the International Association of Geodesy, the International Union of Theoretical and Applied Mechanics and COSPAR (Committee on Space Research). The organizing committee was composed of Dr. KOVALEVSKY chair man, Dr. Yu. V. BATRAKOV representing IAU, Dr. A. H. COOK for lAG, Dr. D. KING-HELE for COSPAR, Prof. M. Roy for IUTAM and Dr. ROSENBERG. I wish to take advantage of the opportunity to thank, on behalf of all the participants, the organizing committee members, Prof. BUCHAR, Dr. RAJSK: I and Dr. SEHNAL, for the kindness and efficiency of their welcome. The interpreters who translated with virtuosity during the whole symposium also deserve our gratitude. I am grateful also for the care and skill with which Springer-Verlag has printed this volume."