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Our vast Universe is filled with an enormous amount of matter and energy, which are the source of large gravitational potentials affecting all physical phenomena. Because this fact about the size and contents of the Universe was not known when our fundamental theories of dynamics and relativity were completed by the 1920s, the current theories - based as they are in empty space - fail to incorporate cosmic gravity. Though the current theories are consistent with the majority of empirical facts, there are some crucial discrepancies, which demand a drastic shift to a cosmic gravitational paradigm for the theories of relativity and dynamics. The book is a detailed and widely accessible account of this paradigm, called Cosmic Relativity, supported by ample empirical evidence. It is established that all motional relativistic effects are cosmic gravitational effects. The new theory of Cosmic Relativity solves and answers all outstanding questions and puzzles about dynamics andrelativity.

This book shows how one can combine Yang-Mills gauge symmetry and effective Einstein-Grossmann metric tensors to tackle physical problems at microscopic, macroscopic and super-macroscopic length scales in inertial frames, including the late-time accelerated cosmic expansion due to baryon masses and charges. The combination of gauge symmetry and effective metric tensor provides a framework and leads to an alternative dynamics of cosmic expansion based on quantum Yang-Mills gravity at a super-macroscopic limit. Together with cosmological principle, one can investigate and derive expanding scale factors, the age of the universe, the cosmic redshift, and the Hubble recession velocity with an upper limit. All these discussions are based on inertial frames with operationally defined space and time coordinates.

A sweeping account of the century of experimentation that confirmed Einstein's general theory of relativity, bringing to life the science and scientists at the origins of relativity, the development of radio telescopes, the discovery of black holes and quasars, and the still unresolved place of gravity in quantum theory.Albert Einstein did nothing of note on May 29, 1919, yet that is when he became immortal. On that day, astronomer Arthur Eddington and his team observed a solar eclipse and found something extraordinary: gravity bends light, just as Einstein predicted. The finding confirmed the theory of general relativity, fundamentally changing our understanding of space and time.A century later, another group of astronomers is performing a similar experiment on a much larger scale. The Event Horizon Telescope, a globe-spanning array of radio dishes, is examining space surrounding Sagittarius A•, the supermassive black hole at the center of the Milky Way. As Ron Cowen recounts, the foremost goal of the experiment is to determine whether Einstein was right on the details. Gravity lies at the heart of what we don't know about quantum mechanics, but tantalizing possibilities for deeper insight are offered by black holes. By observing starlight wrapping around Sagittarius A•, the telescope will not only provide the first direct view of an event horizon—a black hole's point of no return—but will also enable scientists to test Einstein's theory under the most extreme conditions.Gravity's Century shows how we got from the pivotal observations of the 1919 eclipse to the Event Horizon Telescope, and what is at stake today. Breaking down the physics in clear and approachable language, Cowen makes vivid how the quest to understand gravity is really the quest to comprehend the universe.

A brief introduction to gravity through Einstein's general theory of relativityOf the four fundamental forces of nature, gravity might be the least understood and yet the one with which we are most intimate. From the months each of us spent suspended in the womb anticipating birth to the moments when we wait for sleep to transport us to other realities, we are always aware of gravity. In On Gravity, physicist A. Zee combines profound depth with incisive accessibility to take us on an original and compelling tour of Einstein's general theory of relativity. Inspired by Einstein's audacious suggestion that spacetime could ripple, Zee begins with the stunning discovery of gravity waves. He goes on to explain how gravity can be understood in comparison to other classical field theories, presents the idea of curved spacetime and the action principle, and explores cutting-edge topics, including black holes and Hawking radiation. Zee travels as far as the theory reaches, leaving us with tantalizing hints of the utterly unknown, from the intransigence of quantum gravity to the mysteries of dark matter and energy.Concise and precise, and infused with Zee's signature warmth and freshness of style, On Gravity opens a unique pathway to comprehending relativity and gaining deep insight into gravity, spacetime, and the workings of the universe.

By focusing on the mostly used variational methods, this monograph aspires to give a unified description and comparison of various ways of constructing conserved quantities for perturbations and to study symmetries in general relativity and modified theories of gravity. The main emphasis lies on the field-theoretical covariant formulation of perturbations, the canonical Noether approach and the Belinfante procedure of symmetrisation. The general formalism is applied to build the gauge-invariant cosmological perturbation theory, conserved currents and superpotentials to describe physically important solutions of gravity theories. Meticulous attention is given to the construction of conserved quantities in asymptotically-flat spacetimes as well as in asymptotically constant curvature spacetimes such as the Anti-de Sitter space. Significant part of the book can be used in graduate courses on conservation laws in general relativity. THE SERIES: DE GRUYTER STUDIES IN MATHEMATICAL PHYSICS The series is devoted to the publication of monographs and high-level texts in mathematical physics. They cover topics and methods in fields of current interest, with an emphasis on didactical presentation. The series will enable readers to understand, apply, and develop further, with sufficient rigor, mathematical methods to given problems in physics. The works in this series are aimed at advanced students and researchers in mathematical and theoretical physics. They can also serve as secondary reading for lectures and seminars at advanced levels.

From Science News comes a captivating anthology of articles exploring the concept of gravity and Albert Einstein's enduring influence on the way humans understand it. From the ancient Greeks to Galileo to Sir Isaac Newton, gravity has long fascinated scientists and laypeople alike. One of the most mysterious forces in the universe, gravity as a theory has developed and changed over the centuries, but no single person has had as much to do with its evolution, and our understanding, as Albert Einstein. This collection of articles from the Science News archive looks at Einstein's development of the general theory of relativity and considers its impact. Thanks to his revisions of Newton's theories, we have come to predict and understand phenomena such as gravitational waves, black holes, and the expansion of the universe. But Einstein did not just provide explanations—his work has raised new questions that scientists continue to investigate today. Since 1921, Society for Science & the Public has facilitated global understanding of important scientific discoveries and issues. Since the first publication of the Science News-Letter in 1922, they have grown their audience to millions of readers each year. Now, Science News exposes new readers to thrilling concepts and innovative theories in Einstein's Gravity.

The book points out what has gone wrong with physics since Einstein's formulation of this theory of general relativity a century ago. It points out inconsistencies and fallacies in the standard model of the big bang and the inflationary scenario which was supposed to have overcome those shortcomings, the evolution of string theory from a theory of the strong interaction to a theory of gravitation and quantum mechanics which has not produced a single verifiable prediction, and what it has accomplished is reaffirming wrong results like the entropy of a black hole, which is not an entropy at all. There have even been attempts to demote gravity to an emergent phenomenon with catastrophic effects. We know exactly what happened at 10-34 seconds after the big bang, but do not know how fast gravity propagates, whether gravitational waves exist, and what are the limits of Newton's law. Attempts to rectify this are the prediction of dark energy/matter, which has never been observed nor ever will, and MOND. The latter is really not a modification of Newtonian mechanics, but a transformation of a dynamical law into a statistical one.

Einstein's general theory of relativity is introduced in this advanced undergraduate and beginning graduate level textbook. Topics include special relativity, in the formalism of Minkowski's four-dimensional space-time, the principle of equivalence, Riemannian geometry and tensor analysis, Einstein field equation, as well as many modern cosmological subjects, from primordial inflation and cosmic microwave anisotropy to the dark energy that propels an accelerating universe. The author presents the subject with an emphasis on physical examples and simple applications without the full tensor apparatus. The reader first learns how to describe curved spacetime. At this mathematically more accessible level, the reader can already study the many interesting phenomena such as gravitational lensing, precession of Mercury's perihelion, black holes, and cosmology. The full tensor formulation is presented later, when the Einstein equation is solved for a few symmetric cases. Many modern topics in cosmology are discussed in this book: from inflation, cosmic microwave anisotropy to the'dark energy'that propels an accelerating universe. Mathematical accessibility, together with the various pedagogical devices (e.g., worked-out solutions of chapter-end problems), make it practical for interested readers to use the book to study general relativity and cosmology on their own.

This book brings Einstein's general relativity into action in new ways at scales ranging from the tiny Planck scale to the scale of immense galactic clusters. It presents the case that Einstein's theory of gravity can describe the observed dynamics of galaxies without invoking the unknown “dark matter” required in models based on Newtonian gravity.Drawing on the author's experience as a lecturer and on his own research, the book covers the essentials of Einstein's special and general relativity at a level accessible to undergraduate students. The early chapters provide a compact introduction to relativity for readers who have little or no background in the subject. Hermann Bondi's very transparent approach to special relativity is expanded to resolve the “twin paradox” using only elementary mathematics. In later chapters, general relativity is used to extend the concept of the Planck scale, to address the role of the cosmological term and to analyze the concept of “time machines”.

'The Universal Force'conveys the excitement of science and nature's mysteries. It describes gravitation as seen by examining the achievements of those great scientists who have struggled with the seemingly simple facts and managed to extract some truth about the nature of gravity, its origins, and its effects. Gravity is intimately tied up with motion, and therefore with time and space, and is responsible for planetary systems, the evolution of stars and the existence of black holes and the very beginning of the Universe. It is the universal force, and to look at gravity is to look at the deepest aspects of nature. The historical context from Aristotle's teleology through Galileo's conflict with the Church, to Newton's law, and Einstein's curved space time, displays the evolution of the science of gravity as one of the greatest and most fascinating human achievements. Contrary to popular opinion, all important science can be understood by anyone, with or without a scientific background. This book shows that the beauty and mysteries of science can be shared with everyone.

Written for advanced undergraduate and graduate students, this is a clear mathematical introduction to Einstein's theory of general relativity and its physical applications. Concentrating on the theory's physical consequences, this approachable textbook contains over 300 exercises to illuminate and extend the discussion.