Home > Encyclopedia of Science > Relativity, Theory of

• Classical physics
• Relative motion
• The special theory
• Energy and mass
• Other implications
• Tests of relativity
• Significance of relativity theory

The theory of relativity is an approach for studying the nature of the universe. It was devised by German-born American physicist Albert Einstein (1879–1955) in the first quarter of the twentieth century. The theory is usually separated into two parts: the special theory and the general theory. The outlines of the special theory were first published by Einstein in 1905 and dealt with physical systems in uniform velocity. (The term velocity refers both to the speed with which an object is moving and to...