An Introduction To Relativity

In 1905, Albert Einstein published his "Special Theory of Relativity", a simple and elegant hypothesis that made a number of remarkable assertions: That nothing could exceed the speed of light; that clocks in motion run slower than clocks at rest; that the length of an object in motion is less than that of the object at rest; and that a moving object's mass increases.

These assertions have been confirmed by observations and experiment, and are now generally accepted. Einstein used his theory of Special Relativity as a springboard for a much more comprehensive "Theory of General Relativity", which is also generally accepted. This document explains how Special Relativity works and provides a short survey of General Relativity. To understand this document, a reader will need to be comfortable with high-school algebra and geometry. Readers will also need to be familiar with fundamental concepts of physics.