Gravity S Century

“This gracefully written history of twentieth-century gravity research” brings to life the discoveries and developments that confirmed the theory of relativity (Publishers Weekly, starred review). 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, the Event Horizon Telescope examined the space surrounding Sagittarius A*, the supermassive black hole at the center of the Milky Way, to determine whether Einstein was right on the details. In Gravity’s Century, award-winning science writer Ron Cowen brings to life the incredible scientific journey between these two events and sheds light on their groundbreaking implications. From the development of radio telescopes to the discovery of black holes and quasars, and the still-unresolved place of gravity in quantum theory, Cowen breaks down the physics in clear and approachable language. Gravity’s Century vividly demonstrates how the quest to understand gravity is really the quest to comprehend the universe./

"An account of the century of experimentation that confirmed Einstein's 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 findings 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, one 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."--

Ron Cowen offers a sweeping account of the century of experimentation that has consistently confirmed Einstein’s general theory of relativity. He shows how we got from Eddington’s pivotal observations of the 1919 eclipse to the Event Horizon Telescope, aimed at starlight wrapping around the black hole at our galaxy’s center.

The author of this history of mankind’s increasingly successful attempts to understand, to measure and to map the Earth’s gravity field (commonly known as ‘little g’ or just ‘g’) has been following in the footsteps of the pioneers, intermittently and with a variety of objectives, for more than fifty years. It is a story that begins with Galileo’s early experiments with pendulums and falling bodies, progresses through the conflicts between Hooke and Newton and culminates in the measurements that are now being made from aircraft and satellites. The spectacular increases in accuracy that have been achieved during this period provide the context, but the main focus is on the people, many of whom were notable eccentrics. Also covered are the reasons WHY these people thought their measurements would be useful, with emphasis in the later chapters on the place of ‘g’ in today’s applied geology, and on the ways in which it is providing new and spectacular visions of our planet. It is also, in part, a personal memoir that explores the parallels between the way fieldwork is being done now and the difficulties that accompanied its execution in the past. Selected topics in the mathematics of ‘g’ are discussed in a series of short Codas.

Every scientific fact was born as an opinion about the unknown - a hypothesis. Opinion gradually becomes fact as evidence piles up to support a theory. But what if there are two theories, each of which has produced a myriad of things that correspond perfectly to the phenomena but can't be combined into one? One theory replaced the mystery of gravity with a precise model of space and time. The other theory replaced the mystery of matter with a description of quantum particles. As we understand our universe, we keep each in its own domain: space and time for very large things, particles for the very small ones. However, 13.8 billion years ago, those two incompatible domains belonged to a single realm. Who in the current or future generations of physicists will crack this seemingly impossible puzzle? This, contends the author, is not just a big question, but the biggest question in physics in our century. Combining Ickes's first-hand knowledge with a robust argument and intellectual playfulness, this fascinating book succeeds in making a notoriously difficult subject accessible to all readers interested in a better grasp of our universe. -Vincent Icke is professor of theoretical astrophysics at Universiteit Leiden, professor of cosmology at the University of Amsterdam, visual artist, and writer.

‘Gravity, a Geometrical Course’ presents general relativity (GR) in a systematic and exhaustive way, covering three aspects that are homogenized into a single texture: i) the mathematical, geometrical foundations, exposed in a self consistent contemporary formalism, ii) the main physical, astrophysical and cosmological applications, updated to the issues of contemporary research and observations, with glimpses on supergravity and superstring theory, iii) the historical development of scientific ideas underlying both the birth of general relativity and its subsequent evolution. The book is divided in two volumes. Volume Two is covers black holes, cosmology and an introduction to supergravity. The aim of this volume is two-fold. It completes the presentation of GR and it introduces the reader to theory of gravitation beyond GR, which is supergravity. Starting with a short history of the black hole concept, the book covers the Kruskal extension of the Schwarzschild metric, the causal structures of Lorentzian manifolds, Penrose diagrams and a detailed analysis of the Kerr-Newman metric. An extensive historical account of the development of modern cosmology is followed by a detailed presentation of its mathematical structure, including non-isotropic cosmologies and billiards, de Sitter space and inflationary scenarios, perturbation theory and anisotropies of the Cosmic Microwave Background. The last three chapters deal with the mathematical and conceptual foundations of supergravity in the frame of free differential algebras. Branes are presented both as classical solutions of the bulk theory and as world-volume gauge theories with particular emphasis on the geometrical interpretation of kappa-supersymmetry. The rich bestiary of special geometries underlying supergravity lagrangians is presented, followed by a chapter providing glances on the equally rich collection of special solutions of supergravity. Pietro Frè is Professor of Theoretical Physics at the University of Torino, Italy and is currently serving as Scientific Counsellor of the Italian Embassy in Moscow. His scientific passion lies in supergravity and all allied topics, since the inception of the field, in 1976. He was professor at SISSA, worked in the USA and at CERN. He has taught General Relativity for 15 years. He has previously two scientific monographs, “Supergravity and Superstrings” and “The N=2 Wonderland”, He is also the author of a popular science book on cosmology and two novels, in Italian.

Reinventing Gravity introduces general readers to Moffat's groundbreaking new ideas about the universe.