E = mc2 theory of relativity theory and quantum mechanics are two basic branch of modern physics , classical mechanics laid the foundation of classical physics , but for high speed objects and microscopic condition of objects, Newton's laws are no longer applicable.
An important conclusion of the theory of relativity is talking about mass and energy. Based on the special relativity ,mass and energy are not interchangeable, while in classical mechanics, mass and energy are mutually independent, but in relativistic mechanics, energy and mass are interchangeable.
Albert Einstein(14 March 1879 – 18 April 1955) was a German-born theoretical physicist, came up with some of the most important discoveries and theories in all of science.Some people consider him to be one of the smartest people of the 20th century. Not only best known for formula E = mc2 for his services to theoretical physics, but also laid much of the foundation for modern physics. here are example of his discoveries. In 1905, Einstein came up with the concept that light is made up of particles called photons. Most scientists of his day didn't agree, but later experiments in 1919 showed this to be the case. This became an important discovery for many branches of science and he was awarded the Nobel Prize for Physics in 1921. working with another scientist called Satyendra Bose, they discovered another state of matter. Sort of like liquid or gas or solid states.
In January 1933 after the Nazi regime in Germany, grab, Einstein move to university of Princeton and 1940 he became U.S. citizen. In 1939, he was informed that its uranium nuclear fission chain reaction found in the Hungarian physicist L. Szilard, driven by a letter to President Roosevelt, the proposed development of the atomic bomb,