Albert Einstein. Computer illustration of the German-American physicist Albert Einstein (1879- 1955) seen with an astronomical artwork and equations including E=mc2. In this famous equation, E stands for energy, m for mass and c for the speed of light. In 1905 Einstein published papers on the photoelectric effect, Brownian motion (the random movement of suspended particles) and, most significantly, the special theory of relativity which included the equation E=mc2. In 1915 he published the general theory of relativity. His paper on the photoelectric effect won Einstein the 1921 Nobel Prize for physics.