Albert einstein

Albert Einstein ( /ˈælbərt ˈaɪnstaɪn/; German: [ˈalbɐt ˈaɪnʃtaɪn] ( listen); 14 March 1879 – 18 April 1955) was a German-borntheoretical physicist who developed the general theory of relativity,effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics[2][3] and the most influential physicist of the 20th century. While best known forhis mass–energy equivalence formula E = mc2 (which has been dubbed "the world's most famous equation"),[4] he received the1921 Nobel Prize in Physics "for his services to theoretical physics, and especiallyfor his discovery of the law of the photoelectric effect".[5] The latter was pivotal in establishing quantum theory within physics.
Near the beginning of his career, Einstein thought that Newtonianmechanics was no longer enough to reconcile the laws ofclassical mechanics with the laws of the electromagnetic field. This led to the development of his special theory of relativity. He realized,however, that the principle of relativity could also be extended to gravitational fields, and with his subsequent theory of gravitation in 1916, he published a paper on the general theory of relativity.He continued to deal with problems of statistical mechanics and quantum theory, which led to his explanations of particle theory and the motion of molecules. He also investigated the thermalproperties of light which laid the foundation of the photon theory of light. In 1917, Einstein applied the general theory of relativity to model the structure of the universe as a whole.[6]
He was visitingthe United States when Adolf Hitler came to power in 1933, and did not go back to Germany, where he had been a professor at the Berlin Academy of Sciences. He settled in the U.S., becoming a citizen in1940.[7] On the eve of World War II, he helped alert President Franklin D. Roosevelt that Germany might be developing an atomic weapon, and recommended that the U.S. begin similar research; this...