Dieses Buch ist bis heute eine der popularsten Darstellungen der Relativitatstheorie geblieben. In der vorliegenden Version haben J. Ehlers und M. Poessel vom Max-Planck-Institut fur Gravitationsphysik (Albert-Einstein-Institut) in Golm/Potsdam den Bornschen Text kommentiert und einen den anschaulichen, aber prazisen Stil Borns wahrendes, umfangreiches Erganzungskapitel hinzugefugt, das die sturmische Entwicklung der Relativiatatstheorie bis hin zu unseren Tagen nachzeichnet. Eingegangen wird auf Gravitationswellen und Schwarze Loecher, auf neuere Entwicklungen der Kosmologie, auf Ansatze zu einer Theorie der Quantengravitation und auf die zahlreichen raffinierten Experimente, welche die Gultigkeit der Einsteinschen Theorie mit immer groesserer Genauigkeit bestatigt haben. Damit bleibt dieses Buch nach wie vor einer der unmittelbarsten Zugange zur Relativitatstheorie fur alle die sich fur eine uber das rein popularwissenschaftliche hinausgehende Einfuhrung interessieren.

In recent years the subject of relativistic fluid dynamics has found substantial applications in astrophysics and cosmology (theories of gravitational collapse, models of neutron stars, galaxy formation), as well as in plasma physics (relativistic fluids have been considered as models for relativistic particle beams) and nuclear physics (relativistic fluids are currently used in the analysis of the heavy ion reactions). Modern methods of analysis and differential geometry have now also been introduced. The International C.I.M.E. Course brought together expertise and interest from several areas (astrophysics, plasma physics, nuclear physics, mathematical methods) to create an appropriate arena for discussion and exchange of ideas. The main lecture courses introduced the most significant aspects of the subject and were delivered by leading specialists. The notes of these have been written up for this volume and constitute an up-to-date and thorough treatment of these topics. Several contributions from the seminars on specialized topics of complementary interest to the courses are also included.

Roger Penrose, one of the most accomplished scientists of our time, presents the only comprehensive and comprehensible account of the physics of the universe. From the very first attempts by the Greeks to grapple with the complexities of our known world to the latest application of infinity in physics, "The Road to Reality" carefully explores the movement of the smallest atomic particles and reaches into the vastness of intergalactic space. Here, Penrose examines the mathematical foundations of the physical universe, exposing the underlying beauty of physics and giving us one the most important works in modern science writing.

The authors discuss such topics as "impacts with asteroids, the greenhouse effect, nuclear winter, fringe catastrophism, supernovae and an assessment of risks." (New Scientist)

I remember once watching a presentation of the creation of the universe in a planetarium. It was a fascinating experience: lights flashing, particles appearing to rush by as an explosive roar echoed throughout the planetarium. Then suddenly ... black ness. And after a few seconds ... tiny lights--stars blinking into existence. I tried to imagine myself actually going back to this event. Was this really what it was like? It was an interesting facsimile, but far from what the real thing would have been like. The creation of the universe is an event that is impossible to imagine accurately. Fortunately, this has not discouraged peo ple from wondering what it was like. In Creation I have attempted to take you back to the begin ning-the big bang explosion-so that you can watch the uni verse grow and evolve. Starting with the first fraction of a sec ond, I trace the universe from its initial dramatic expansion through to the formation of the first nuclei and atoms. From here I go to the formation of galaxies and the curious distribu tion they have taken in space. Finally I talk about the formation of elements in stars, and the first life on the planets around them.

The Symposium was held at the Great Wall Sheraton Hotel in Beijing, China in the period August 25-30, 1986. The decision to concentrate on the observational aspects of modern cosmology was taken in part because this conference has come in a period when there have been several international meetings on one aspect of modern cosmology, namely the early universe and its possible relationship to particle physics. While that approach is extremely exciting, it has the disadvantage that its connection with much of observational cosmology is very indirect. Thus there has been little opportunity to discuss critically the wealth of new data that are now becoming available which bear on the structure and evolution of the Universe but not always on its early history. This Symposium was planned to cover all aspects of observational cosmology, with only comparatively minor excursions into theory. Nearly 200 participants attended from 21 countries. A total of 26 invited papers and 73 contributed papers were given. This meant that everyone worked hard and long from 9 A.M. to about 5:30 P.M. for five of the six days of the conference. In addition to oral contributions, space was made available for poster papers and 56 of these were available for study for the duration of the conference.

Since the last International Astronomical Union Symposium that dealt with matters cosmological, there have been dramatic advances, both on the observational and theoretical fronts. Modern high-efficiency detectors have made possible extensive magnitude-limited redshift surveys, which have permitted observational cosmologists to construct three-dimensional maps of large regions of space. What seems to emerge is a distribution of matter in extensive, flat, but probably filamentary, and possibly interconnected, superclusters, serving as interstices between vast voids in space. Meanwhile, theoretical ideas that were highly speculative a few years ago have begun to be taken seriously as possibly describing conditions in the very early universe. And brand new ideas, such as that of the inflationary universe, hold promise of solving outstanding observational, theoretical, and philosophical problems in cosmology. A new look at grand unified theories and concepts of supersymmetry have brought observational and theoretical cosmologists to a common meeting ground with modern particle physicists.

Every night, above our heads, a drama of epic proportions is playing out. Diamond planets, zombie stars, black holes heavier than a billion Suns. The cast of characters is extraordinary, and each one has its own incredible story to tell. We once thought of our Earth as unique, but we have now discovered thousands of alien planets, and that's barely a fraction of the worlds that are out there. And there are more stars in the Universe than grains of sand on every planet in the Solar System. But amid all this vastness, the Milky Way Galaxy, our Sun and the Earth are home to the only known life in the Universe - at least for now. With a foreword from Professor Brian Cox, and access to all the latest stunning NASA photography, Andrew Cohen takes readers on a voyage of discovery, via the probes and telescopes exploring the outer reaches of our galaxy, revealing how it was formed and how it will inevitably be destroyed by the enigmatic black hole at its heart. And beyond our galaxy, the expanding Universe, which holds clues to the biggest mystery of all - how did it all begin? We now know more about those first moments of existence than we ever thought possible, and hidden in this story of how it all began are the clues to the fate of the Universe itself and everything in it.

Jan H. Dort's work Ad: r>iaan Blaauw Meritus Emeritus Harry van der Laan 21 Jan Hendrik Dort and Dutch astronomy H. G. van Bueren 31 Dort's scientific importance on a world-wide scale Bengt Stromgren 39 Gart and international co-operation in astronomy D. H. Sadler 45 Reminiscences of the early nineteen-twenties Peter Van de Kamp 51 The first five years of Jan Dort at Leiden, Bart J. Bok 1924-1929 55 Early galactic structure Per Olof Lindblad 59 Early galactic radio astronomy at Kootwijk C. A. Muller 65 W. N. Christiansen Dort and his large radiotelescope 71 Ten years of discovery with Dort's Synthesis Radio Telescope R. J. Allen and R. D. Ekers 79 Gort's work on comets Maarten Schmidt 111 The evolution of ideas on the Crab Nebula L. WoUjer 117 Gort's work reflected in current studies of galactic CO W. B. Burton 123 On high-energy astrophysics V. L. Ginzburg 129 Dort and extragalactic astronomy Margaret and Geoffrey Burbidge 141 Birthday wishes John A. and Janette Wheeler 151 The Earth and the Universe Abraham H. Oort 153 The challenge of Jan Dort J. H. Bannier 157 Jan Dort at the telescope Fjeda Walraven 161 Gart Westerhout Personal recollections 163 Style of research Henk van de Hulst 165 Manuscript Jan H.

From the world-renowned physicist and bestselling author of The Elegant Universe and The Fabric of the Cosmos, a captivating exploration of deep time and humanity's search for purpose In both time and space, the cosmos is astoundingly vast, and yet is governed by simple, elegant, universal mathematical laws. On this cosmic timeline, our human era is spectacular but fleeting. Someday, we know, we will all die. And, we know, so too will the universe itself. Until the End of Time is Brian Greene's breathtaking new exploration of the cosmos and our quest to understand it. Greene takes us on a journey across time, from our most refined understanding of the universe's beginning, to the closest science can take us to the very end. He explores how life and mind emerged from the initial chaos, and how our minds, in coming to understand their own impermanence, seek in different ways to give meaning to experience: in story, myth, religion, creative expression, science, the quest for truth, and our longing for the timeless, or eternal. Through a series of nested stories that explain distinct but interwoven layers of reality-from the quantum mechanics to consciousness to black holes-Greene provides us with a clearer sense of how we came to be, a finer picture of where we are now, and a firmer understanding of where we are headed. Yet all this understanding, which arose with the emergence of life, will dissolve with its conclusion. Which leaves us with one realization: during our brief moment in the sun, we are tasked with the charge of finding our own meaning. Let us embark.

337 F(e) = (z) where the angle between the directions III and 112 is equal to 8. r is the angular diameter effective distance of the epoch for recombination. F (8) ~ve have F(e) : f (e) ~ (S" ) e. . ~ is a Bessel function. It is assumed here that the spectrum of gravitational waves takes the form 1\ hI'::: hoK for all relevant wavelengths, a is beam width of the radio antenna, d\= d~, and ~ is the duration of the process of recombinations in \-time. The results for different beam widths are shown in Fig. 1. 338 I. D. NOVIKOV 1-. . . -__ 0. 5 1 1. 5 2 e' 0. 5 o and for a l' (solid line) and Fig. 1. The function f(8) for n for a = 2' (dotted line). These formula should be used in analysing the implications of future observations. Comparison with the observational data now available enables us to establish an upper limit for the energy density of long gravitational waves. This method is most sensitive for gravitational waves with A ~ ct The fluctuations ~; due to these waves have scale ~ 0. 03 GW rec 4 radian. If, according to modern observations, we take ~; < 10- , then 8 26 ~GW/Ey < 10- for those gravitational waves which have A = 5. 10 cm GW today where Ey is the energy density of relict radiation. The fluctuations ~TT due to long gravitational waves with A = ct .

The significance of the present IAU symposium, "The Large Scale Structure of the Universe," fortunately requires no elaboration by the editors. The quality of the wide range of observational and theoretical astrophysics contained in this volume speaks for itself. The published version of the proceedings contains all the contributions presented at the symposium with the exception of the introductory lecture by V. A. Ambartsumian. Contributed papers, short contributions and discussions have been included according to the recommendations of the IAU. Many people contributed to the success of the symposium. First of all, thanks are due to the USSR Academy of Sciences and to the Estonian Academy of Sciences for sponsoring this symposium in Tallinn. The efforts of Academician K. Rebane, President of the Estonian Academy of Sciences, are particularly appreciated. The astronomical hosts of the symposium were the members of the W. Struve Astrophysical Observatory of Tartu who made outstanding efforts to lavish participants with Estonian hospitality which was greatly appreciated and enjoyed by them and their guests. The members of the Scientific and Local Organising Committees are listed below and we thank all of them for their contributions which were central to the success of the symposium. In addition are listed members of the Technical Organising Committee who were responsible for all details of the organisation and whose vigilance ensured that all aspects of the symposium ran smoothly and efficiently. Their contributions are all gratefully acknowledged.

One of the most powerful questions we ask about the cosmos is: Are we alone? The Possibility of Life traces the history of our understanding of what and where life in the universe could be, from Galileo and Copernicus through to our current tracking of exoplanets in the Goldilocks zone, where life akin to ours on Earth might exist. Along the way, Jaime Green studies insights from a long tradition of science fiction that uses imagination to extrapolate and construct worlds, in turn inspiring scientists and their research. Bringing together expert interviews, cutting-edge astronomy, philosophical inquiry and pop culture touchstones ranging from A Wrinkle in Time to Star Trek, The Possibility of Life delves into our evolving conception of the cosmos to pose an even deeper question: what does it mean to be human?

be hoped. We have improved measurements by at best a factor of 3. So thIS paper, unfortunately, IS really a status report rather than a progress report. There are, however, a few new results to mention. I shall present the results wIthout glVlng any detaIls of the experImental apparatus. In general, sources of error and problems in these measurements are not determined by the apparatus itself. The most important new result IS that of Paul Henry (1971), who employed a radiometer mounted on a rotatmg platform suspended beneath a balloon. Because he employed a rotatmg platform he was able to look for amsotropy over a WIde area area of the sky (about one-half of the northern hemIsphere), not Just a CIrcle of con- stant dechnatIOn. In a smgle mght, he was able to obtam enough data to establIsh a value for the component of the 'dIpole' anisotropy parallel to the spm aXIS of the Earth It IS LI T = (3. 2 +- 0 8) x 10-3 K in the direction (X = I Oh-ll hand () = - 30 . HIS results are conSIstent WIth the earher results of Conkhn (1969), but provIde the Im- portant addItIonal datum that the motion of the Earth with respect to the co-movmg coordinate system (and parallel to the spm aXIS of the Earth) IS small. MeanwhIle, Conklin refined and repeated hIS earher measurement and reduced the statIstical error. The results of his work are reported m the IAU Symp. 44 (1972).

Over the last forty years, scientists have uncovered evidence that if the Universe had been forged with even slightly different properties, life as we know it - and life as we can imagine it - would be impossible. Join us on a journey through how we understand the Universe, from its most basic particles and forces, to planets, stars and galaxies, and back through cosmic history to the birth of the cosmos. Conflicting notions about our place in the Universe are defined, defended and critiqued from scientific, philosophical and religious viewpoints. The authors' engaging and witty style addresses what fine-tuning might mean for the future of physics and the search for the ultimate laws of nature. Tackling difficult questions and providing thought-provoking answers, this volumes challenges us to consider our place in the cosmos, regardless of our initial convictions.

Up to date and comprehensive in its coverage, Neutrinos in Particle Physics, Astrophysics and Cosmology reviews the whole landscape of neutrino physics, from state-of-the-art experiments to the latest phenomenological and theoretical developments to future advances. With contributions from internationally recognized leaders in the field, the book covers the basics of the standard model and neutrino phenomenology. It also discusses Big Bang cosmology, neutrino astrophysics, CP violation, leptogenesis, and solar neutrino physics, including the standard solar model. The contributors present experimental aspects of accelerator and reactor neutrino experiments as well as nuclear physics experiments that deal with neutrinoless double beta decay and tritium decay. They also focus on neutrino detectors, neutrino beams, and the neutrino factory. Drawn from the lectures of the Scottish Universities Summer Schools in Physics, this resource provides an essential foundation for anyone working in the exciting area of neutrino physics.

From Nobel Prize-winning physicist P. J. E. Peebles, the story of cosmology from Einstein to today Modern cosmology began a century ago with Albert Einstein's general theory of relativity and his notion of a homogenous, philosophically satisfying cosmos. Cosmology's Century is the story of how generations of scientists built on these thoughts and many new measurements to arrive at a well-tested physical theory of the structure and evolution of our expanding universe. In this landmark book, one of the world's most esteemed theoretical cosmologists offers an unparalleled personal perspective on how the field developed. P. J. E. Peebles was at the forefront of many of the greatest discoveries of the past century, making fundamental contributions to our understanding of the presence of helium and microwave radiation from the hot big bang, the measures of the distribution and motion of ordinary matter, and the new kind of dark matter that allows us to make sense of these results. Taking readers from the field's beginnings, Peebles describes how scientists working in independent directions found themselves converging on a theory of cosmic evolution interesting enough to warrant the rigorous testing it passes so well. He explores the major advances-some inspired by remarkable insights or perhaps just lucky guesses-as well as the wrong turns taken and the roads not explored. He shares recollections from major players in this story and provides a rare, inside look at how science is really done. A monumental work, Cosmology's Century also emphasizes where the present theory is incomplete, suggesting exciting directions for continuing research.

A Brief History of Time, published in 1988, was a landmark volume in science writing and in world-wide acclaim and popularity, with more than 9 million copies in print globally. The original edition was on the cutting edge of what was then known about the origins and nature of the universe. But the ensuing years have seen extraordinary advances in the technology of observing both the micro- and the macrocosmic world--observations that have confirmed many of Hawking's theoretical predictions in the first edition of his book.

Now a decade later, this edition updates the chapters throughout to document those advances, and also includes an entirely new chapter on Wormholes and Time Travel and a new introduction. It make vividly clear why A Brief History of Time has transformed our view of the universe.

'Remember to look up at the stars and not down at your feet' How did it all begin? Is there a God? Throughout his extraordinary career, Stephen Hawking expanded our understanding of the universe and unravelled some of its greatest mysteries. In How Did It All Begin? the world famous cosmologist and bestselling author of A Brief History of Time explores the fundamental questions of our existence. 'A brilliant mind' Daily Telegraph Brief Answers, Big Questions: this stunning paperback series offers electrifying essays from one of the greatest minds of our age, taken from the original text of the No. 1 bestselling Brief Answers to the Big Questions.

In the final book of his astonishing career, Carl Sagan brilliantly examines the burning questions of our lives, our world, and the universe around us.

These luminous, entertaining essays travel both the vastness of the cosmos and the intimacy of the human mind, posing such fascinating questions as how did the universe originate and how will it end, and how can we meld science and compassion to meet the challenges of the coming century? Here, too, is a rare, private glimpse of Sagan’s thoughts about love, death, and God as he struggled with fatal disease.

Ever forward-looking and vibrant with the sparkle of his unquenchable curiosity, Billions & Billions is a testament to one of the great scientific minds of our day.

This Third Edition provides a concise, authoritative study of cosmology at an introductory level. Starting from elementary principles and the history of cosmology, the text carefully guides the student on to curved spacetimes, general relativity, black holes, cosmological models, particles and symmetries, and phase transitions.

Extensively revised, this latest edition includes broader and updated coverage of distance measures, gravitational lensing and waves, dark energy and quintessence, the thermal history of the Universe, inflation, large scale structure formation, and the ‘cosmological coincidence’problem.

• Illustrated throughout and comprehensively referenced with problems at the end of each chapter.
• Includes more material on observational astrophysics and expanded sections on astrophysical phenomena.
• Latest observational results from the WMAP satellite and the 2 degree Field Galaxy Redshift Survey.