xxii CONTENTS In 1957 I was invited to work on special problems in Magnetic Laboratory of the Academy of Sciences of USSR as a Head of Department of Magnetic Hydrodynamics. In few years this Laboratory was transfered into the I. V. Kurchatov Institute of Atomic Energy, and I continued to work in this Institute up to 1965. In parallel I also worked at Moscow State University as Professor in the CR and Space Research Team. I also gave lectures in Irkutsk, Alma-Ata, Nalchik, Tbilisi, Erevan, Samarkand, and others places. Over about 40 years of teaching under my supervision more than hundred graduate students and scientists in USSR and some other countries gained their Ph. D. and several tenths became Doctors of Science. As my hobby I continued to work in CR research, and as Vice-President of All-Union Section of Cosmic Rays and Radiation Belts, took an active part in preparing the Soviet net of CR stations to the IGY (International Geophysical Year, 1957-1958): we equipped all soviet stations in USSR and in Antarctica with standard cubic and semi-cubic muon telescopes and with neutron monitors of IGY (or Simpson’s) type. In connection with preparing for the IQSY (the International Quiet Sun Year, 1964-1965), the soviet net of CR stations was extended about two fold and they were equipped with neutron super-monitors of IQSY type (with an effective surface about 10 times bigger than the previous monitor of IGY type).

This Atlas provides a complete set of images of Local Group Galaxies (excluding the three for which identification atlases are already in print) and shows the most important objects, including many thousands of individual stars and interstellar objects.

This book deals with stars during a short episode before they undergo a ma­ jor, and fatal, transition. Soon the star will stop releasing nudear energy, it will become a planetary nebula for abrief but poetic moment, and then it will turn into a white dwarf and slowly fade out of sight. Just before this dramatic change begins the star has reached the highest luminosity and the largest diameter in its existence, and while it is a star detectable in galaxies beyond the Local Group, its structure contains already the inconspicuous white dwarf it will become. It is called an "asymptotic giant branch star" or "AGB star". Over the last 30 odd years AGB stars have become a topic of their own although individual members of this dass had already been studied for cen­ turies without realizing what they were. In the early evolution, so called "E-AGB"-phase, the stars are a bit bluer than, but otherwise very similar to, what are now called red giant branch stars (RGB stars). It is only in the sec­ ond half of their anyhow brief existence that AGB stars differ fundamentally from RGB stars.

Galaxy collisions are the key process in building galaxies, triggering the formation of stars and the build-up of heavy elements that allow the formation of planets and solar systems. This book presents the revolutionary research advances achieved in the last decade and lucidly explains the underlying dynamical processes.

While most amateur astronomers know about the red shift, have a general idea of the way that the emission and absorption lines in stellar spectra provide an insight into the atomic processes of the star, it is unusual to find someone who has any kind of detailed knowledge. The reason isn’t lack on interest – far from it – but is because all the books currently available are pitched at professional astronomers and degree students, and are to say the least, difficult to read.

The present book is a translation of the original German edition (published in 1982) with some minor corrections and improvements. The guide to sup­ plementary and advanced literature given in the Appendix, however, has been brought up to date. This book is addressed primarily to students taking astronomy as a prin­ cipal or subsidiary subject, and to scientists of related fields, but amateur as­ tronomers should also be able to profit from it. For most chapters an elementary knowledge of mathematics and physics will be sufficient, however, Chaps. 5 and 6 impose somewhat greater requirements. In addition the reader should already be acquainted with the basic concepts of stellar physics as treated in introduc­ tory books, including the spectral types, the system of stellar magnitudes and colours, absolute magnitudes and luminosities, the Herlzsprung-Russell dia­ gram and its interpretation.

IAU Symposium Number 52 on Interstellar Dust and Related Topics was held at Albany, N.Y., on the campus of the State University of New York at Albany from May 29 to June 2, 1972. The members of the Organizing Committee were: Dr A. D. Code, University of Wisconsin, Madison, Wis., U.S.A. Dr B. D. Donn, Goddard Space Flight Center, Greenbelt, Md., U.S.A. Dr A. Elvius, Stockholm Observatory, Saltsjobaden, Sweden. Dr T. Gehrels, Lunar and Planetary Laboratory, University of Arizona, Tucson, Ariz., U.S.A. Dr J. M. Greenberg (Chairman), State University of New York at Albany, Albany, N.Y., U.S.A. Dr H. C. van de Hulst, Sterrewacht, Leiden, Holland. Dr S. B. Pikel'ner, Sternberg Astronomical Institute, Moscow, U.S.S.R. Dr E. E. Sal peter, Cornell University, Ithaca, N.Y., U.S.A. Dr B. E. Turner, National Radio Astronomy Observatory, Charlottesville, Va., U.S.A. The suggestion was first made in 1971 that a symposium on interstellar grains would be timely. The response to the first preliminary announcement, which was sent out on November 29, 1971, was well beyond our expectations. The meeting was locally sponsored by the State University and by Dudley Observatory.

"Era tempo che un’opera in italiano fosse consacrata interamente alle galassie, spiegando in modo semplice e accessibile a tutti ciò che conosciamo. È quello che è riuscito ad Alessandro Boselli, specialista di formazione stellare nelle galassie, il quale utilizza, oltre alle sue proprie osservazioni, i dati dei satelliti astronomici.
L’autore ha saputo mettersi alla portata di un pubblico interessato ma non specialista per spiegare la natura e l’evoluzione delle galassie, e il suo entusiasmo è comunicativo. Il suo libro è magnificamente illustrato da fotografie e da immagini ottenute dai piu grandi telescopi terrestri o spaziali. Queste immagini non sono solamente belle da guardare perché grazie alle spiegazioni che ne sono date ci permettono di capire quello che sono veramente le galassie. Raccomando calorosamente la lettura di questo libro che, partendo da basi molto semplici, ci da una visione completa e attuale degli elementi costitutivi dell’Universo."

The majority of books dealing with prospects for interstellar flight tackle the problem of the propulsion systems that will be needed to send a craft on an interstellar trajectory. The proposed book looks at two other, equally important aspects of such space missions, and each forms half of this two part book.

Galaxies are perhaps the most popular of all visual targets that are sought after by visual observers. At present the only way to get up-to-date information, is to query various (often highly technical) speciality books or digging deeply into the Internet.

Living material contains about twenty different sorts of atom combined into a set of relatively simple molecules. Astrobiologists tend to believe that abiotic mater­ ial will give rise to life in any place where these molecules exist in appreciable abundances and where physical conditions approximate to those occurring here on Earth. We think this popular view is wrong, for it is not the existence of the building blocks of life that is crucial but the exceedingly complicated structures in which they are arranged in living forms. The probability of arriving at biologically significant arrangements is so very small that only by calling on the resources of the whole universe does there seem to be any possibility of life originating, a conclusion that requires life on the Earth to be a minute component of a universal system.

In this work, Prof. Arnold Hanslmeier provides modern and fascinating astronomical knowledge. The book begins with a description of the origin of the universe and goes on to dark matter, black holes and the formation of the solar system. Finally, it is rounded off at the end by the exciting question: Are we alone in the universe?

This book discusses such topics as extra-galactic radio sources, unified models of black hole accretion, wave propagation theory, cryovolcanism in the solar system, and the early oceans of Earth.