UNIVERSITY CONNECT::Relativity: The Special and the General Theory BOOK

This republication of Albert Einstein's introduction to his theory of relativity, written for the layperson, includes commentary by Robert Geroch (physics, University of Chicago) on the modern understanding of relativity, plus an introduction by Robert Penrose (mathematics, emeritus, Oxford University), framing Einstein's work within the history of science, and an essay on the cultural legacy of relativity theory by David C. Cassidy (natural sciences, Hofstra University). Einstein's preface, 32 chapters, and three appendices were originally published in 1920. The original version of Roger Penrose's introduction was first published in 2004 by The Folio Society Ltd

The theory of relativity is not as complicated as we believe. Theory of relativity proved to be ground breaking discovery in the field of physics. It is simple science which we use in our everyday experience. Einsteins in 1905 with his famous paper On the Electrodynamics of Moving Bodies explains his Special Relativity Theory. Special relativity (SR) theory deals with things that are moving near or at the speed of light. The new concept that is derived from relativity is based on the fact that laws of physics are the same in all inertial that is., non accelerating reference frames. And the speed of light in the free space is constant.

According to SR space and time are not separate concepts. If we move an object relative to another, the time is a mixture of space and time. This means, among other events is seen as simultaneous for one observer may not be simultaneous as seen by another observer moving relative to the first.

Special relativity explains how the law of science shall be the same no matter where they are located or in which direction it is moving, when there is absence of gravitation. It would be easy to tackle relativity in terms of space-time coordinate. In special relativity, we deal only with flat space-time.

General relativity theory published in 1916 is based on the same theory of special relativity. The distinction is that general theory explains the force of gravity in terms of a curving four-dimensional space-time. According to Einstein the forces of acceleration and gravity are equivalent. His publication also states that all physical laws can be formulated so as to be valid for any observer, regardless of the observer’s motion.

According to this theory nothing can travel faster than the speed of light, however the gravitational attraction between two different objects would be stronger when they are closer to each other. If we move farther away or closer together the change in the attraction is instantaneous. This theory also considers a much wider case of space-times and talks about that the laws of physics are the same in all reference frames.

This theory allows us to work on gravity as it allows us to define a local Lorentz frame along with the equivalence principle as well as the principle of general relativity.
Einstein’s equation elaborates that matter tells space-time how to curve, and space-time tells matter how to move. This theory has been confirmed by a variety of experiments. It also calls for the existence of such things as black holes and gravitational waves.