Albert Einstein (14 March 1879 – 18 April 1955), a German-born theoretical physicist who discovered the theory of general relativity and the theory of gravitation, leading to a revolution in physics. For this achievement, Einstein is often dubbed the father of modern physics. He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect". He also developed the photon theory of light and came up with explanations of particle theory and the motion of molecules. In 1917, Einstein applied the general theory of relativity to model the structure of the universe as a whole. Einstein's prolific scientific publications, as well as his great intelligence and originality have made the word "Einstein" synonymous with genius.