Albert Einstein (14 March 1879 – 18 April 1955) was a German-born American scientist. He worked on theoretical physics. He developed the theory of relativity. He received the Nobel Prize in Physics in 1921 for theoretical physics.
His famous equation is (E = energy, m = mass, c = speed of light (energy = mass × speed of light²).
At the start of his career, Einstein didn't think that Newtonian mechanics was enough to bring together the laws of classical mechanics and the laws of the electromagnetic field. Between 1902–1909 he made the theory of special relativity to fix it.
Einstein also thought that Isaac Newton's idea of gravity was not completely correct. So, he extended his ideas on special relativity to include gravity. In 1916, he published a paper on general relativity with his theory of gravitation.
In 1933, Einstein was visiting the United States but in Germany, Adolf Hitler and the Nazis came to power (this is before World War II). Einstein, being of Jewish ethnicity, did not return to Germany due to Hitler’s anti-Semitic policies. He lived in the United States and became an American citizen in 1940. On the beginning of World War II, he sent a letter to President Franklin D. Roosevelt explaining to him that Germany was in the process of making a nuclear weapon; so Einstein recommended that the U.S. should also make one. This led to the Manhattan Project, and the U.S. became the first nation in history to create and use the atomic bomb (not on Germany but on Japan). Einstein and other physicists like Richard Feynman who worked on the Manhattan Project later regretted that the bomb was used on Japan.
Einstein lived in Princeton and was one of the first members invited to the Institute for Advanced Study, where he worked for the remainder of his life.
He is now thought to be one of the greatest scientists of all time.
His contributions helped lay the foundations for all modern branches of physics, including quantum mechanics and relativity.