Time is an illusion. Although the laws of physics create a powerful impression that time is flowing, in fact there are only timeless 'nows'. In THE END OF TIME, the British theoretical physicist Julian Barbour describes the coming revolution in our understanding of the world: a quantum theory of the universe that brings together Einstein's general theory of relativity, which denies the existence of a unique time, and quantum mechanics, which demands one. Barbour believes that only the most radical of ideas can resolve the conflict between these two theories: that there is, quite literally, no time at all. This is the first full-length account of the crisis in our understanding that has enveloped quantum cosmology. Unifying thinking that has never been brought together before in a book for the general reader, Barbour reveals the true architecture of the universe and demonstrates how physics is coming up sharp against the extraordinary possibility that the sense of time passing emerges from a universe that is timeless. The heart of the book is the author's lucid description of how a world of stillness can appear to be teeming with motion: in this timeless world where all possible instants coexist, complex mathematical rules of quantum mechanics bind together a special selection of these instants in a coherent order that consciousness perceives as the flow of time. Finally, in a lucid and eloquent epilogue, the author speculates on the philosophical implications of his theory: Does free will exist? Is time travel possible? How did the universe begin? Where is heaven? Does the denial of time make life meaningless? Written with exceptional clarity and elegance, this profound and original work presents a dazzlingly powerful argument that all will be able to follow, but no-one with an interest in the workings of the universe will be able to ignore.

Eleven most important original papers on special and general theories. Seven by Einstein, two by Lorentz, one each by Minkowski and Weyl.

Relativity, almost a hundred years old in its classic Einsteinian form, is one of the most fascinating threads running through science from Galileo’s day to ours. This book, based on a short course at the University of Sussex, presents relativity as a natural outgrowth of dynamics: the concepts are introduced through careful physical reasoning and simple mathematics, and are then applied over a wide range, well meshed with current undergraduate syllabuses. Features

• An accessible introduction through pre-Einstein relativity
• Scrupulously assessed experimental evidence (mostly modern)
• Elementary mathematics, aimed at a working acquaintance with kinematics, energy and momentum conservation, and the propagation of plane waves
• The book includes many carefully chosen examples and student problems

Aimed at advanced undergraduates, this self-contained textbook covers the key ideas of special and general relativity together with their applications. The textbook introduces students to basic geometric concepts, such as metrics, connections and curvature, before examining general relativity in more detail. It shows the observational evidence supporting the theory, and the description general relativity provides of black holes and cosmological space-times. The textbook is in full colour, with numerous worked examples and exercises with solutions. Key points and equations are highlighted for easy identification, and each chapter ends with a summary list of important concepts and results. This textbook provides the essential background for an up-to-date discussion of modern observational cosmology. Each chapter builds on the previous one as concepts are developed, making it ideal for self-study. Accompanying resources to this textbook are available at: http: //www.cambridge.org/features/astrophysics

Unlike many textbooks or popular science books, A Simple Guide to Popular Physics has truly been crafted for the uninitiated or those spooked by the subject's complexity. Harris's inviting guide promises to give "absolute beginners" from "teens to centenarians" a basic grounding in particle physics, quantum physics, and cosmology-all without making readers do math. With the goal of introducing the basics and encouraging readers to explore more deeply afterwards, Harris notes "Like the fish we have no notion of what is beyond the boundaries of our knowledge, but unlike the fish, we know there is something." He starts by presenting those boundaries, the fundamentals of classic physics (Newton's law, states of matter, types of energy), with crisp clarity before laying out an accessible explanation of Einstein's theory of relativity, the structure of the atom, the mysteries of quantum mechanics and cosmology. Readers will not need to search online for key terms or explanations of concepts that have been glossed over. Instead, one by one, with patience and good humor, Harris introduces each of these building blocks of our universe, taking a little time to invite readers to contemplate the momentousness of the information, as in the chapter titled nothing less than "What Is Reality?" The watchword, here, is clarity, which Harris offers throughout, with professional illustrations and illuminating accounts of experiments and breakthroughs, offering a solid foundation for understanding and future reading.

Recent cosmological observations have posed a challenge for traditional theories of gravity: what is the force driving the accelerated expansion of the universe? What if dark energy or dark matter do not exist and what we observe is a modification of the gravitational interaction that dominates the universe at large scales? Various extensions to Einstein's General Theory of Relativity have been proposed, and this book presents a detailed theoretical and phenomenological analysis of several leading, modified theories of gravity. Theories with generalised curvature-matter couplings are first explored, followed by hybrid metric-Palatini gravity. This timely book first discusses key motivations behind the development of these modified gravitational theories, before presenting a detailed overview of their subsequent development, mathematical structure, and cosmological and astrophysical implications. Covering recent developments and with an emphasis on astrophysical and cosmological applications, this is the perfect text for graduate students and researchers.

Here a physicist and a professor of literature guide general readers through the ideas that revolutionized our conception of the physical universe.

Somewhere near the heart of existence, shimmers the ethereal beauty of the mystery of Time. Though seemingly familiar to us all, time harbours secrets that penetrate the very deepest levels of reality, and though we feel certain in our conviction that we're swept forth upon the crest of its never-ending flow, with Einstein's discovery of relativity came what is perhaps the most stunning realisation in the entire history of scientific thought - the wondrously breathtaking revelation that in reality, there's actually no such thing as the passage of time... How can this extraordinary truth be reconciled with the reality we so surely suppose to experience? What does it mean for the very human concerns of life and death, free will, identity, and self? What should it mean for our philosophy? And how should it inform our world view? The search for answers leads through the fantastical realm of quantum physics, and the strange parallel worlds it describes, as we discover that the answers which such questions provoke, are perhaps even more profound than the questions themselves. Buried deep within the riddle of time, lies the staggering beauty of the world. As we peel back the layers to try and sneak a glimpse into eternity, we find a light shining not only upon the nature of reality, but on the nature of ourselves...

These two volumes are the proceedings of a major International Symposium on General Relativity held at the University of Maryland in March 1993 to celebrate the sixtieth birthdays of Professor Charles Misner and Professor Dieter Brill. The volumes cover classical general relativity, quantum gravity and quantum cosmology, canonical formulation and the initial value problem, topology and geometry of spacetime and fields, mathematical and physical cosmology, and black hole physics and astrophysics. As invited articles, the papers in these volumes have an aim which goes beyond that of a standard conference proceedings. Not only do the authors discuss the most recent research results in their fields, but many also provide historical perspectives on how the subjects have developed and offer individual insights in their search for new directions.