The articles collected in this volume cover topics ranging from Planck-scale physics to galaxy clustering. They deal with various new ideas from cosmology, astrophysics and particle physics that might lead to a better understanding of our physical universe. Among the topics covered are inflationary models, nucleosynthesis, dark matter, large-scale clustering, cosmic microwave background radiations and more. The book addresses researchers but it also gives a good overview of the subject for graduate students in astrophysics and particle physics.

Le ciel est, par-dessus le toit, The sky is, up above the roof, Si bleu, si calme So blue, so calm Un arbre, par-dessus Je toit, A tree there, up above the roof, Berce sa palme. Waves leaves of palm. La cloche, dans le ciel qu'on voit, A church bell, in the sky I see, Doucement tinte. Softly tolls. Un oiseau, sur l'arbre qu'on voit, A bird, upon the tree I see, Chante sa plainte. Sadly calls. PAUL VERLAINE Like Verlaine, we are in prison. The prison is our Earth, "which is so pretty"; our atmosphere and its clouds, its "marvellous clouds." (You would think that Verlaine, Prevert and Baudelaire had been comparing notes ) The sky is up above the roof... A tree there, up above the roof... Stars in the sky, like birds ... their rays, like bells (and here we are with Apollinaire ) What we see opens the way to what we guess at; what we observe Ieads us towards the unobservable. A poem releases images, and the invisible grows big with reality. Astronomcrs are a little like poets (indirectly from the Greek 7tostco, make): they make the universe by interpreting messages, extrapolating spectra, and inventing 'models' of the cosmos or of stars - fictional constructions whose observable part constitutes only a small fraction of the whole, and which only the inductive logic of the theoretician allows us to consider as representing unique physical reality.

The present volume colleets the review and contributed papers presented at the Europhysics Study Conferenee "Acere- tion Disks and Magnetie Fields in Astrophysies" held in Noto, Sicily, Italy, from 16 to 21 June 1988, under the High Patronage of the President of the Italian Republie and the 10ea1 patronage of the Cent ro di Studi Superiori e di Rieer- ehe (Center for Advaneed Study and Research), a seientific institution supported by the City of Nota and the Oniversity of Catania. The attendanee to the Conferenee was limited to about fifty seleeted partieipants from Canada, China, Denmark, Franee, Germany F.R., Italy, Japan, the Netherlands, Spain, Sl~itzerland. Onited Kingdom and Onited States, in order to give the meeting the character and appearance of areal lolorkshop, whose main aim was to highl ight a varied but same wh at uni fied picture of the interact ion, in di fferent astrophysical systems, of rotation, turbulenee and magnetism, with speeifie referenee to aeeretion disks.

The universe is the largest system of all. It consists of elementary particles bound together by gravitational, electromagnetic and nuclear forces. Its structural hierar chy in space (from atomic nuclei to supergalaxies) and its evolutionary sequence (from the fireball to the diversity of present forms) is governed by the properties of elementary particles and their interactions. This book is an attempt to interpret the structure and evolution of the universe in terms of elementary particles and of their interactions. This book is intended to present a background for students in astronomy and related sciences, such as geophysics, meteorology, plasma physics, chemistry, nuc lear physics, space sciences and some others. The universe forms a general framework fo: all the phenomena studied by these sciences. It was possible to squeeze an extensive range of topics from various disciplines into one book of acceptable size only under some severe limitations: (a) no references are given; (b) arguments are shortcut; (c) quantities are often expressed in the order of magnitude; and (d) formulae have been limited to a minimum. Often more hypo theses or theories exist for a phenomenon. We have chosen only one. The preference for a theory or hypothesis may be personal and the theory itself may later prove incorrect. But, many theories about a particular phenomenon would cover many pages and might lead to confusing effects."

IAU Colloquium No. 71 had its immediate origins in a small gathering of people interested. in the optical and UV study of flare stars which took place during the 1979 Montreal General Assembly. We recognized that a fundamental change was taking place in the study of these objects. Space-borne instruments (especially lUE and Einstein) and a new genera tion of ground-based equipment were having a profound effect on the range of investigations it was possible to make. To extract maximum benefit from these new possibilities it would be necessary as never before to have good communication with colleagues in other disciplines, for instance, . with atomic and solar physicists. Similarly, studies of phenomena associated with the outer atmospheres of the late-type stars could now hope to give significant insights into certain aspects of solar activity. So, in view of the wide range of backgrounds of those participating, the meeting had an unusually high proportion of invited reviews while most of the contributed papers were presented as posters. It is gratifying that in the short time since the meeting a good deal of correspondence has been received from participants remarking on the success of this format. Once the decision had been taken in principle to hold the meeting, a very considerable amount of work fell on the two organizing committees, viz. the Scientific and Local Organizing Committees. The Scientific Organizing Committee was chaired by D.J. Mullan and consisted of A.D."

The five lectures presented in this volume address very timely mathematical problems in relativity and cosmology. "Part I" is devoted to the initial value and evolution problems of the Einstein equations. Especially it deals with the Einstein-Yang-Mills-Boltzmann system, fluid models with finite or infinite conductivity, global evolution of a new (two-phase) model for gravitational collapse and the structure of maximal, asymptotically flat, vacuum solutions of the constraint equations which have the additional property of containing trapped surfaces. "Part II" focuses on geometrical-topological problems in relativity and cosmology: on the role of cosmic censorship for the global structure of the Einstein-Maxwell equations and on the mathematical structure of quantum conformal superspace.

This book contains the proceedings of a workshop held in Schloss Ringberg to assess developments in molecular cloud research over the last 25 years, and to discuss trends for future research in the field of molecular line astronomy. The topics include the morphology, formation, and lifetimes of molecular clouds, and their relation to star formation. Also, the chemical and isotopic content of these clouds is reviewed, and comparisons with molecular clouds in external galaxies are made. This rather complete survey of this important field of research addresses researchers in astronomy and students alike."

The symposium Star Clusters in the Era of Large Surveys was held in Lisbon on Sep 9-10 during the JENAM 2010. It served as a platform for discussing what and how recent, on-going and planned large-area ground-based and space-based surveys can contribute to producing a major leap in this research field, which has a strong European history.

Scientific topics addressed included: cluster searches, clustered vs. isolated star formation, large-scale star formation, enrichment of the field population, structure, populations and evolution of the Milky Way, cluster dynamics (internal and within the Milky Way), variability of stars in clusters (from time-resolved surveys), analysis techniques for large samples and archiving.

This proceedings book provides a snapshot of the ongoing discussion on the role of large surveys in star cluster research, and serves as a reference volume for the state-of-the art in the field."

This volume contains the results of research and development connected with the creation oftelescopes intended for the new regions of the spectrum mastered by astronomy: the x-ray, submillimeter (far infrared), and radio regions. The creation of x-ray, submillimeter, and radio telescopes and the receiver apparatus connected with them is a complicated and, in many respects, unusual problem. Therefore, the experience accumulated at the Institute of Physics can prove useful to specialists working in this field, This volume is intended for scientists, engineers, and builders occupied in research and development in the fields of x-ray, submillimeter, and radio astronomy as well as for students of advanced courses in these specialties, V CONTENTS A Reflecting X-Ray Telescope for an Orbital Astrophysical Station. * * * * * * * * * 1 I. L, Beigman. L. A. Vainshtein, Yu. P. Voinov, D. A. Goganov, N. I. Komyak, S. L. Mandel'shtam, I. P, Tindo, N, A, Shatskii, and A. I. Shurygin Mirror Systems for X-Ray Telescopes. * * * * * * * * * * * * * * * * * * * * * * * * * * * * 13 I. L. Beigman, L, A. Vainshtein, Yu. P. Voinov, and V. P, Shevel'ko Extra-Atmospheric studies in the Submillimeter Range Using On-Board Telescopes . . * . . * * * * * . . . * . . . * . * . . . * . . * . * * . . . * * . . . * . . * * . 35 A. E. Salomonovich and A. s.

The Ninth Course of the International School of Cosmology and Gravita tion of the Ettore Majorana Centre for Scientific Culture is concerned with "Topological Properties and Global Structure of Space-Time." We consider this topic to possess great importance. Our choice has also been influenced by the fact that there are many quest ions as yet unre solved. Standard general relativity describes space-time as a four-dimensional pseudo-Riemannian manifold, but it does not prescribe its large-scale structure. Inorderto attempt answers to some topological questions, such as whether our universe is open or closed, whether it is orientable, and whether it is complete or possesses singularities, various theoretical approaches to global aspects of gravitational physics are presented here. As topological questions playa role in non-standard theories as weIl, it will be found that some of the lectures and seminar talks in this volume adopt the point of view of standard relativity, whereas others are based on different theories, such as Kaluza-Klein theories, bimetric theories, and supergravity. We have found it difficult to organize these papers into classes, say standard and non-standard theory, or models with and without singularities. One paper, by R. Reasenberg, is experimental. Its purpose was to give the theorists present an inkling of the opportunities, as weIl as the pitfalls, of experimental research in gravitational physics. Accordingly, we have arranged all contributions alphabetically, by first-named) author."

The Hidden Hypotheses Behind the Big Bang It is quite unavoidable that many philosophical a priori assumptions lurk behind the debate between supporters of the Big Bang and the anti-BB camp. The same battle has been waged in physics between the determinists and the opposing viewpoint. Therefore, by way of introduction to this symposium, I would like to discuss, albeit briefly, the many "hypotheses", essentially of a metaphysical nature, which are often used without being clearly stated. The first hypothesis is the idea that the Universe has some origin, or origins. Opposing this is the idea that the Universe is eternal, essentially without beginning, no matter how it might change-the old Platonic system, opposed by an Aristote lian view! Or Pope Pius XII or Abbe Lemaitre or Friedmann versus Einstein or Hoyle or Segal, etc. The second hypothesis is the need for a "minimum of hypotheses" -the sim plicity argument. One is expected to account for all the observations with a mini mum number of hypotheses or assumptions. In other words, the idea is to "save the phenomena", and this has been an imperative since the time of Plato and Aristotle. But numerous contradictions have arisen between the hypotheses and the facts. This has led some scientists to introduce additional entities, such as the cosmologi cal constant, dark matter, galaxy mergers, complicated geometries, and even a rest mass for the photon. Some of the proponents of the latter idea were Einstein, de Broglie, Findlay-Freundlich, and later Vigier and myself.

Advances in the dynamics of stellar systems have been made recently by applying mathematical methods of ergodic theory and chaotic dynamics, by numerous computer simulations, and by observations with the most powerful telescopes. This has led to a considerable change of our view on stellar systems. These systems appear much more chaotic than was previously thought and subject to various instabilities leading to new paths of evolution than previously thought. The implications are fundamental for our views on the evolution of the galaxies and the universe. Such questions are addressed in this book, especially in the 8 review papers by leading experts on various aspects of the N-body problem, explaining at the graduate/postgraduate level the concepts, methods, techniques and results.

Meant as a review for students of astrophysics and particle physics, this book contains a selection of survey articles and seminar reports on "high energy cosmology." Included are contributions on topics ranging from classical cosmology, large scale structure, and primordial nucleosynthesis to quantum cosmology, covering both the theoretical aspects and the most important observations.

The volume consists of up-to-date reviews and a selection of contributed papers on subjects including the structure and physical properties of molecular clouds, their role in the star formation process, their dust and chemical properties, molecular cloud surveys of the Milky Way, cloud evolution, problems in cloud mass determinations (a panel discussion and review), the CO properties of external galaxies, nuclei of galaxies as revealed by molecular observations, and galactic spiral structure as reflected by molecular cloud distributions. The abstracts of poster papers on these topics presented at the conference are also included. This book is both a valuable reference and a compendium of current knowledge in this field. It should be of special interest to all students and researchers who work on the physics of star formation, the interstellar medium, molecular clouds and galactic structure.

This book begins with a very readable survey "The Sun Today" by J.-C. Pecker. It is followed by thorough reviews from leading experts covering theory and observations. The focus shifts from the solar core, studied via neutrino emissions and helioseismology, through the interface regions where it is believed the large-scale magnetic fields are generated, to the corona, where most of the high temperature phenomena characteristic of this region may be studied directly. As energetic particles play such a vigorous role in this part of the sun, a separate session was devoted to their transport and storage in the corona.

The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) is a NASA Explorer mission that is the first space mission dedicated to imaging of the Earth's magnetosphere. IMAGE was launched from Vandenberg AFB into an elliptical polar orbit by a Delta II launch vehicle on March 25, 2000. The two-year prime sci entific mission of IMAGE began on May 25, 2000 after instrument commissioning was successfully completed. IMAGE has now been approved for operation until October 1,2005, and an additional two-year extension is now being considered by NASA. The papers in this volume represent many of the scientific results obtained dur ing the IMAGE prime mission and include some of the early correlative research with ground-based measurements, measurements from other spacecraft such as Cluster II, and relevant theory and modeling programs. All of the reported work is related to the overall IMAGE science objective: How does the magnetosphere respond globally to the changing conditions in the solar wind? IMAGE addresses this question with multi-spectral imaging of most of the important plasma pop ulations of the inner magnetosphere, combined with radio sounding of gradients of total plasma content. The new experimental techniques fall into the following areas: neutral atom imaging (NAI) over an energy range from 10 eV to 500 keY for detection of ionospheric outflow, the plasma sheet, and the ring current; far ultraviolet (FUV) imaging at 121-190 nm for detection of precipitating protons and the global aurora; extreme ultraviolet (EUV) imaging at 30.

The enormous advances in observational techniques over the last two decades has produced a wealth of data and unexpected discoveries which have helped to reshape astrophysics as a field with well-formulated theories and sophisticated numerical calculations. In nuclear particle physics, plasma physics, as well as in general relativity, the Universe has become a laboratory for cutting-edge research. The courses collected in the book are intended to provide students with this insight, giving a general background on each topic such as cosmic rays, nuclear and neutrino astrophysics, solar physics and strong fields, as well as a presentation of the current research and open problems. The book is aimed at graduate students in physics and astrophysics, as well as researchers, bridging a gap between the specialized reviews and the comprehensive books.

This ESO workshop, which took place in September 1995 on a topic that at a first glance could be considered rather specialized, attracted an unpre dictably large number of scientists. This certainly reflects the importance of this field, which has lost its seemingly esoteric character, in a wider astro physical context. To give as much room as possible in these proceedings to the targeted talks, no presentation of the Very Large Telescope Observatory has been included. All readers missing such a presentation are reminded that up-to date in-depth information about the VLT status is available electronically.1 Papers were given concerning observations in the entire electromagnetic spectrum from x-rays to mm-waves, i.e., exceeding 22 octaves in frequency. The VLT as any ground-based optical observatory can only address at best 7 octaves. Nevertheless the VLT, most likely the only ground-based observa tory specifically designed to access all these 7 octaves of the electromagnetic spectrum practically in parallel, will undoubtedly be a tool of extreme value to this field.

The Solar and Heliospheric Observatory (SOHO) is a joint ESA/NASA mission to study the Sun, from its deep core to the outer corona, and the solar wind. SOHO was launched on 2 December 1995 and was inserted into a halo orbit around the L1 Lagrangian point on 14 February 1996. From this vantage point it is continuously monitoring the Sun, the heliosphere, and the solar wind particles that stream toward the Earth. Nominal operations of the SOHO mission started in April 1996 after commissioning of the spacecraft and the scientific payload. Detailed descriptions of the twelve instruments, which represent the most comprehensive set of solar and heliospheric instruments ever developed and placed on the same platform, can be found in "The SOHO" "Mission" ("Solar Physics," Vol. 162, Nos. 1-2, 1995).
This volume contains papers reporting the first scientific results from the SOHO mission as well as descriptions of the in-flight performance of some of the instruments, published in two parts of a "Solar Physics" special (Part I in "Solar Physics," Vol. 170, No. 1; Part II in "Solar Physics," Vol. 175, No. 2). Unique data from the three helioseismology instruments (GOLF, VIRGO, MDI/SOI) provide new insights into the structure and dynamics of the solar interior, from the deep core to the outermost layers of the convection zone. The remote sensing instruments (SUMER, CDS, EIT, LASCO, UVCS, SWAN) present exciting new data on a wide range of topics such as transition region dynamics, coronal plumes, coronal holes, streamers, and coronal mass ejections, giving us our first comprehensive view of the outer solar atmosphere and corona. These data are complemented by energetic particle measurements produced by the ERNE instrument on board SOHO.

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