Introduction to Relativity

This book is a unique, concise, and accessible foundation for the study of special and general relativity. It is written for anyone drawn to the rich intellectual and philosophical implications of relativity, especially undergraduate physics, engineering, and astronomy majors who may go on to study modern astrophysics, cosmology, and unified fiels theories. Special relativity is developed from two basic notions : that force-free frames of reference are indistinguishable and that nature possesses a universal speed limit - the speed of light. Basic results are introduced with a minimum of algebra by constructing clocks and meter sticks so that time dilation, space contraction, and the relativity of simultaneity can be derived, explained, and illustrated. Minkowski diagrams are introduced to visualize these effects concretely. The Twin Paradox is resolved in detail. The roles of force, energy and momentum, and conservation laws in particle collisions are presented and illustrated through discussions and problems. Although many topics of general relativity require some mathematical and physical background, Chapters 7 and 8 of the book successfully describe the core tenets at the basic lever of the previous six chapters on special relativity. The Equivalence Principle is explained as the centerpiece of Einstein's theory of gravity. It states that a uniform gravitational field produces an environment that is physically indistinguishable from that in a uniformly accelerating reference frame. The gravitational red shift, the Twin Paradox as a problem of twins aging at different rates in different gravitational potentials, and the bending of light in a gravitational field are discussed and illustrated. The formulation of gravity as the theory of curved space-time is introduced at an elementary level.