Understanding Relativity

Nonspecialists with no prior knowledge of physics and only reasonable proficiency with algebra can now understand Einstein's special theory of relativity. Effectively diagrammed and with an emphasis on logical structure, Leo Sartori's rigorous but simple presentation will guide interested readers through concepts of relative time and relative space. Sartori covers general relativity and cosmology, but focuses on Einstein's theory. He tracks its history and implications. He explores illuminating paradoxes, including the famous twin paradox, the "pole-in-the-barn" paradox, and the Loedel diagram, which is an accessible, graphic approach to relativity. Students of the history and philosophy of science will welcome this concise introduction to the central concept of modern physics.

The central subject matter of this book is Einstein's special theory of relativiry. While it is a book that is written primarily for a lay audience this does not necessarily mean an audience not versed in the ways of doing science. Rather, this book is written for anyone wishing to consider the nature of the scientific enterprise: where ideas come from, how they become established and accepted, what the relationships are among theories, predictions, and measurements, or the relationship between ideas in a scientific theory and the values held to be important within the larger culture. Some readers will find it strange that I raise any of these issues. It is a common view in our culture that the status of knowledge within science is totally different from the status of knowledge in other areas of human endeavor. The word "science" stems from the Latin word meaning "to know" and indeed, knowledge which scientists acquire in their work is commonly held to be certain, unyielding, and absolute. Consider how we use the adjective "scientific. " There are investors and there are scientific investors. There are socialists and there are scientific socialists. There are exterminators and there are scientific exterminators. We all know how the modifier "scientific" inttudes in our daily life. It is the purpose of this book to challenge the belief that scientific knowledge is different from other kinds of knowledge.

This book bridges the huge gap between popular science and mathematical treatments of Einstein's theories. It explains special and general relativity, gravity, black holes, and gravitational waves, also presenting current ideas about dark matter and dark energy. The explanations are entirely non-mathematical, using many color pictures and clear concepts. In this way, the reader is led to a much deeper understanding than any popular science book can provide. The author has written this book for everyone who wants to go beyond superficial descriptions of relativity's remarkable phenomena, but is not equipped to read the professional literature and complicated math behind the theory. By providing a complete description in terms of concepts and pictures, the book answers many questions about why the theory works as it does. For example, it explains why and how momentum and pressure are related to gravity; why and how mass causes spacetime to curve and how curvature tells objects how to move; it also reveals the origin of the ring seen around the first ever image of a black hole. Not least, the reader will learn in detail how gravitational waves are produced and measured. Since their conception, the theories of relativity have appealed to the public's imagination. Thanks to this book, readers now have the opportunity to convert their fascination with the topic to a deep understanding.

"An extraordinarily well-written, well-researched, and carefully thought out piece of work. . . . The discussions of the paradoxes of relativity and of cosmology are the best discussions of these topics at an elementary level that I have ever seen."—Roger A. Freedman, University of California, Santa Barbara

Clear, concise exposition of both the special and general theories of relativity, intended for nonscientific readers with a knowledge of high school math. Topics include simultaneity, time dilation, length contraction, the possibility of travel to a distant star, non-Euclidean geometries, black holes, and the structure of the universe. 158 illustrations.

In It's About Time, N. David Mermin asserts that relativity ought to be an important part of everyone's education--after all, it is largely about time, a subject with which all are familiar. The book reveals that some of our most intuitive notions about time are shockingly wrong, and that the real nature of time discovered by Einstein can be rigorously explained without advanced mathematics. This readable exposition of the nature of time as addressed in Einstein's theory of relativity is accessible to anyone who remembers a little high school algebra and elementary plane geometry. The book evolved as Mermin taught the subject to diverse groups of undergraduates at Cornell University, none of them science majors, over three and a half decades. Mermin's approach is imaginative, yet accurate and complete. Clear, lively, and informal, the book will appeal to intellectually curious readers of all kinds, including even professional physicists, who will be intrigued by its highly original approach.

One of the subject's clearest, most entertaining introductions offers lucid explanations of special and general theories of relativity, gravity, and spacetime, models of the universe, and more. 100 illustrations.

“One of the best popular accounts of how Einstein and his followers have been trying to explain the universe for decades” (Kirkus Reviews, starred review). Physicists have been exploring, debating, and questioning the general theory of relativity ever since Albert Einstein first presented it in 1915. This has driven their work to unveil the universe’s surprising secrets even further, and many believe more wonders remain hidden within the theory’s tangle of equations, waiting to be exposed. In this sweeping narrative of science and culture, an astrophysicist brings general relativity to life through the story of the brilliant physicists, mathematicians, and astronomers who have taken up its challenge. For these scientists, the theory has been both a treasure trove and an enigma. Einstein’s theory, which explains the relationships among gravity, space, and time, is possibly the most perfect intellectual achievement of modern physics—yet studying it has always been a controversial endeavor. Relativists were the target of persecution in Hitler’s Germany, hounded in Stalin’s Russia, and disdained in 1950s America. Even today, PhD students are warned that specializing in general relativity will make them unemployable. Still, general relativity has flourished, delivering key insights into our understanding of the origin of time and the evolution of all the stars and galaxies in the cosmos. Its adherents have revealed what lies at the farthest reaches of the universe, shed light on the smallest scales of existence, and explained how the fabric of reality emerges. Dark matter, dark energy, black holes, and string theory are all progeny of Einstein’s theory. In the midst of a momentous transformation in modern physics, as scientists look farther and more clearly into space than ever before, The Perfect Theory exposes the greater relevance of general relativity, showing us where it started, where it has led—and where it can still take us.