Albert Einstein

In 1879 Einstein was born in Ulm, Germany, into a secular Jewish family; his father ran an electrical-equipment business, and the family soon moved to Munich. It was an age in which electricity was just beginning to change the world, yet the young Einstein was at odds with the rigid German schoolroom—he loathed rote memorization and preferred to ponder alone why a compass needle turned, or what light would look like if one could catch up with it. After the family business failed, his parents moved to Italy; he followed before finishing secondary school, and even renounced his German citizenship, becoming a stateless young man. This temperament of breaking early from institutions and needing to think everything through for himself ran through nearly his whole life.

His beginnings were not smooth. After graduating from the Swiss Federal Institute of Technology in Zurich he was repeatedly turned down for jobs, and in the end a friend's recommendation got him a minor post at the patent office in Bern. It was in that office, far from academic circles, that 1905 became the miracle year in the history of physics: in his spare time he proposed the light-quantum hypothesis, explained Brownian motion, founded special relativity, and wrote down the equation everyone would later know, E=mc². An outsider to the establishment, armed with nothing but pen, paper, and imagination, shook the foundations of space and time that had stood since Newton.

Fame followed. He held a succession of teaching posts and moved to Berlin, and in 1915 completed the far grander general theory of relativity, reconceiving gravity as the curvature of spacetime itself. The 1919 solar-eclipse observations confirmed his prediction of the bending of starlight, and overnight he went from scholar to world celebrity. Thereafter he won the Nobel Prize and lectured around the globe, becoming the public face of science; yet he held to the anti-war stance he had openly declared during the First World War, using his renown as a tool to speak out for peace and justice.

The shadows of the age closed in at last. After the Nazis came to power, Einstein, being Jewish, never returned to Germany; his property was confiscated and his works burned, and he went into exile in the United States, settling in Princeton. In 1939, out of fear that the Nazis might be first to master nuclear weapons, he signed the famous letter to Roosevelt—a letter that indirectly spurred the development of the atomic bomb, and became a heavy burden on his conscience in his later years. Witnessing the power of nuclear weapons after the war, he turned into one of the most steadfast advocates of nuclear disarmament and human rights.

In his later years Einstein returned, in a sense, to where he began: a solitary seeker unwilling to follow the crowd. He declined the invitation to become President of Israel, devoted the rest of his life to the grand ambition of unifying gravity and electromagnetism, and stubbornly refused to accept the probabilistic nature of quantum mechanics, leaving behind the words “God does not play dice.” That pursuit remained unfinished when he died in 1955. But his true legacy lies not in any single unsolved equation, but in his proof that the most profound scientific revolutions can begin with an ordinary person's pure and uncompromising curiosity about the world.