Beyond Einstein’s Gravity is a graduate level introduction to extended theories of gravity and cosmology, including variational principles, the weak-field limit, gravitational waves, mathematical tools, exact solutions, as well as cosmological and astrophysical applications. The book provides a critical overview of the research in this area and unifies the existing literature using a consistent notation. Although the results apply in principle to all alternative gravities, a special emphasis is on scalar-tensor and f(R) theories. They were studied by theoretical physicists from early on, and in the 1980s they appeared in attempts to renormalize General Relativity and in models of the early universe. Recently, these theories have seen a new lease of life, in both their metric and metric-affine versions, as models of the present acceleration of the universe without introducing the mysterious and exotic dark energy. The dark matter problem can also be addressed in extended gravity. These applications are contributing to a deeper understanding of the gravitational interaction from both the theoretical and the experimental point of view. An extensive bibliography guides the reader into more detailed literature on particular topics.

Einstein's gravity theory—his general theory of relativity—has served as the basis for a series of astonishing cosmological discoveries. But what if, nonetheless, Einstein got it wrong? Since the 1930s, physicists have noticed an alarming discrepancy between the universe as we see it and the universe that Einstein's theory of relativity predicts. There just doesn't seem to be enough stuff out there for everything to hang together. Galaxies spin so fast that, based on the amount of visible matter in them, they ought to be flung to pieces, the same way a spinning yo-yo can break its string. Cosmologists tried to solve the problem by positing dark matter—a mysterious, invisible substance that surrounds galaxies, holding the visible matter in place—and particle physicists, attempting to identify the nature of the stuff, have undertaken a slew of experiments to detect it. So far, none have. Now, John W. Moffat, a physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, offers a different solution to the problem. The cap­stone to a storybook career—one that began with a correspondence with Einstein and a conversation with Niels Bohr—Moffat's modified gravity theory, or MOG, can model the movements of the universe without recourse to dark matter, and his work chal­lenging the constancy of the speed of light raises a stark challenge to the usual models of the first half-million years of the universe's existence. This bold new work, presenting the entirety of Moffat's hypothesis to a general readership for the first time, promises to overturn everything we thought we knew about the origins and evolution of the universe.

Veteran plasma physicist John Brandenburg reveals the new theory that finally accomplishes what Einstein failed to do: the GEM Unification Theory proves the mathematical and physical interrelation of the forces of gravity and electromagnetism! This theory vindicates Einstein's dedication to unifying the fields in the final labor of his life. His quest became legendary, then mythic, until the whole idea was dismissed as myth by other physicists; the gravity-electromagnetism problem pursued by Einstein until his death became regarded like the ancient Greek problem of squaring the circle-an epic puzzle with no solution. But the other physicists were wrong, as Brandenburg shows. It turns out the fields can be unified-the circle can be squared-and this has vast implications for the future of humankind. Brandenburg starts out by tracing the evolution of thought on the two long-term forces of nature, gravity and electromagnetism, from ancient times to the modern day. He shows the intricate interweaving of Einstein's work with that of other physicists, including Sarkharov and his "zero point” theory of gravity and the hidden fifth dimension of Kaluza and Klein. He also traces the surprising, hidden influence of Nikola Tesla on Einstein's life. This book shows how, despite Einstein's errors in the details, the successful GEM Unification Theory is built on his basic hypothesis that gravity and electromagnetic forces could be unified, and that both controlled gravity and a new view of the cosmos follow: hydrogen, the basic building block of the universe, can be unified with the vacuum itself! The universe is self-renewing, a sort of "evergreen cosmos.” Brandenburg describes control of space-time geometry through electromagnetism, and states that faster-than-light travel will be possible in the future. Anti-gravity through electromagnetism is possible, which upholds the basic "flying saucer” design utilizing "The Tesla Vortex.” A must read for any person interested in UFOs and leading-edge physics. See the physics used at Area 51 explained!

What is superstring theory and why is it important? Can superstrings offer the fulfilment of Einstein's lifelong dream of a Theory of Everything? Co-authored by one of the leading pioneers in superstrings, this book approaches these scientific questions, looking at the scientific research.

A spacetime appetizer -- Relatively speaking -- Einstein on trial -- Wave talk and bar fights -- The lives of stars -- Clockwork precision -- Laser quest -- The path to perfection -- Creation stories -- Cold case -- Gotcha -- Black magic -- Nanoscience -- Follow-up questions -- Space invaders -- Surf's up for Einstein wave astronomy

Beyond Einstein: Perspectives on Geometry, Gravitation, and Cosmology explores the rich interplay between mathematical and physical ideas by studying the interactions of major actors and the roles of important research communities over the course of the last century.

This book serves two main purposes: firstly, it shows, in a simple way, how the possible existence of an extra-spatial dimension would affect the predictions of four-dimensional General Relativity, a model known as the Brane world; secondly, it explains, step-by-step, a new technique called Minimal Geometric Deformation, which was introduced for the purpose of solving the correspondingly modified Einstein field equations. This method gave rise to the Gravitational Decoupling in General Relativity, which is widely used to solve the Einstein field equations in various contexts.