Fans of "Asterix the Gallic" know well that the only fear of people in Brittany is that the sky falls upon their head. So it must have been a shock for them (the fans of Asterix) to learn that a horde of Physicists and Dynamicists (some of them being actually Roman - ils sont fous ces Romains!) invaded the bay of Saint-Brieuc and spend a full week conjuring all the nastiness that the sky has in reserve, revelling in the horrors hidden beyond the blue dome; they talked with delight about "asteroids", "comets" and "meteor streams"; they grinned at the idea of "artificial satellites", these pots and pans of space always ready to fall upon you; some of them said strange things about the Moon, the planets, and evoked the "rings" of Saturn or of some other of their gods. One evening, a Roman from Pisa went as far as cornering some inhabitants in the large hut they used for their witchcraft and filled them with terror by describing the fate of the poor dinosaurs victims of a particularly nasty asteroid (or was it a comet?). You will be surprized to learn that Bretons did not exact a spectacular revenge for these offenses. On the contrary.

Planet Earth is part of our Galactic environment, not just the product of it, and it is still today influenced by phenomena related to Galactic forces. Specifically, our planet is affected by its near environment, in particular the small bodies in the Solar System. This book reviews the processes which cause the collisions of these small bodies with the Earth as well as the consequences of such collisions. The various articles take the reader through the Galaxy-Solar System connection to the orbital dynamics of the small bodies and to their number and distribution in near-Earth space. The hazards of the impacts of small bodies on Earth are evaluated, and the geophysical records of such impacts are discussed. The book takes the reader to the forefront of research on both impact cratering and the origin and evolution of small bodies in the Solar System. Thus it brings together two subjects, geophysics and astronomy, which are usually discussed in separate volumes but are closely knit together in this particular area of research.

This book on recent investigations of the dynamics of celestial bodies in the solar and extra-Solar System is based on the elaborated lecture notes of a thematic school on the topic, held as a result of cooperation between the SYRTE Department of Paris Observatory and the section of astronomy of the Vienna University. Each chapter corresponds to a lecture of several hours given by its author(s). The book therefore represents a necessary and very precious document for teachers, students, and researchers in the ?eld. The ?rst two chapters by A. Lemaˆ ?tre and H. Skokos deal with standard topics of celestial mechanics: the ?rst one explains the basic principles of resonances in mechanics and their studies in the case of the Solar System. The differences between the various cases of resonance (mean motion, secular, etc. ) are emphasized together with resonant effects on celestial bodies moving around the Sun. The second one deals with approximative methods of describing chaos. These methods, some of them being classical, as the Lyapounov exponents, other ones being developed in the very recent past, are explained in full detail. The second one explains the basic principles of resonances in mechanics and their studies in the case of the Solar System. The differences between the various cases of resonance (mean motion, s- ular, etc. ) are emphasized together with resonant effects on celestial bodies moving around the Sun. The following three chapters by A. Cellino, by P. Robutel and J.

Astronomy and Astrophysics Abstracts aims to present a comprehensive documen tation ofthe literatme concerning all aspects of astronomy, astrophysics, and their border fields. lt is devoted to the recording, summarizing, and indexing of the relevant publications throughout the world. Astronomy and Astrophysics Abstracts is prepared by a special department of the Astronomisches Rechen-Institut under the auspices of the International Astronomical Union. Volume 40 records literatme published in 1985 and received before February 15, 1986. Some older documents which we received late and which arenot surveyed in earlier volumes are included too. We acknowledge with thanks contributions of our colleagues all over the world. We also express our gratitude to all organiza tions, observatories, and publishers which provide us with complimentary copies of their publications. Starting with Volume 33, all the recording, correction, and data processing work was dorre by means of computers. The recording was dorre by om technical staff members Ms. Helga Ballmann, Ms. Mona El-Choura (t), Ms. Monika Kohl, Ms. Sylvia Matyssek. Ms. Karirr Burkhardt, Ms. Susanne Schlötelbmg, Mr. Mar tin Schlötelburg, and Mr. Stefan Wagner supported om task by careful proof reading. lt is a pleasure to thank them all for their encomagement.

An authoritative introduction for graduate students in the physical sciences, this textbook explains the wide variety of physical, chemical, and geological processes that govern the motions and properties of planets. The second edition of this award-winning textbook has been substantially updated and improved. It now contains a reorganized discussion of small bodies, including a detailed description of the Kuiper belt and asteroid belt; a significantly expanded chapter on extrasolar planets and what they tell us about planetary systems; and appendixes providing a glossary of acronyms, tables of key spacecraft, a summary of observing techniques, and a sampling of very recent images. With over 300 exercises to help students apply the concepts covered, this textbook is ideal for courses in astronomy, planetary science and earth science, and well suited as a reference for researchers. Color versions of many figures and movie clips supplementing the text are available at www.cambridge.org/9780521853712.

IAU Transactions are published as a volume corresponding to each General Assembly. Volume A is produced prior to the Assembly and contains Reports on Astronomy, prepared by each Commission President. The intention is to summarize the astronomical results that have affected the work of the Commission since the production of the previous Reports up to a time which is about one year prior to the General Assembly. Volume B is produced after the Assembly and contains accounts of Commission Meetings which were held, together with other material. The reports included in the present volume range from outline summaries to lengthy compilations and references. Most reports are in English.

Analysis of the orbital motion of the Earth, the Moon and other planets and their satellites led to the discovery that all bodies in the Solar System are moving with the first cosmic velocity of their proto parents. The mean orbital velocity of each planet is equal to the first cosmic velocity of the Protosun, the radius of which is equal to the semi-major axis of the planet’s orbit. The same applies for the planets’ satellites. All the small planets, comets, other bodies and the Sun itself follow this law, a finding that has also been proven by astronomical observations. The theoretical solutions based on the Jacobi dynamics explain the process of the system creation and decay, as well as the nature of Kepler’s laws.