Einstein and Relativity.

Albert Einstein electrified the physics community in the United States with his special theory of relativity in 1905 and his general theory of relativity in 1916. In his special theory of relativity Einstein posited that space and time are not absolute and independent realities. Indeed, the word relativity indicates that motion, space, and time cannot be measured from a fixed point but are relative to the observer measuring them. The speed of light, however, is a constant in all frames of reference. As an object approaches the speed of light, it appears to contract in the direction of motion; its mass increases; and time, as measured by a clock moving with the object, slows. Einstein asserted that mass and energy are interchangeable properties: E=mc2, where energy is said to be equivalent to mass times the square of the speed of light. Since the speed of light is 186,000 miles per second, Einstein's...