Relativity

The general theory of relativity, developed in the early 20th century, originally attempted to account for certain anomalies in the concept of relative motion. But it has developed into one of the most important basic concepts in physical science. The theory of relativity, developed primarily by German American physicist Albert Einstein, is the basis for later demonstration by physicists of the essential unity of matter and energy, of space and time, and of the forces of gravity and acceleration.