Albert Einstein 

The work of German-born mathematician and physicist Albert Einstein has made him one of the most famous scientists in history. He overturned many of the long-established ideas of the English physicist Isaac Newton (1642–1727), by introducing revolutionary new theories about the nature of time, space, energy, and gravity. Einstein became a U. S. citizen in 1940. He opposed war – but ironically his theories were eventually used to produce nuclear bombs, the most destructive weapons known to humanity. Einstein saw many of his theories confirmed during his lifetime, and others were proved after his death.