Newton Born: The Mind That Unified Physics Arrives on Christmas Day

Isaac Newton was born on Christmas Day, 1642, according to the Julian calendar then in use in England, which corresponds to January 4, 1643, on the Gregorian calendar that the rest of Europe had already adopted. The discrepancy between calendar systems is why different historical sources give different birth dates, and it is the reason Newton appears twice in the historical record on different days. He was born in Woolsthorpe Manor, Lincolnshire, three months after his father's death, so premature and small that his mother reportedly said he could have fit inside a quart mug. She remarried when he was three, leaving him with his maternal grandmother, and this early abandonment left psychological marks he carried throughout his life. He spent his adult years as Lucasian Professor of Mathematics at Cambridge, where he published the Principia Mathematica in 1687, the most important scientific work ever written, unifying the laws of motion and gravitation into a single mathematical framework that explained everything from falling apples to planetary orbits. He also ran the Royal Mint with an administrative ruthlessness that surprised everyone who knew him as a reclusive academic. He prosecuted counterfeiters personally, attending interrogations and sometimes visiting prisoners in disguise to extract confessions. He feuded viciously with Gottfried Leibniz over who had invented calculus, with Robert Hooke over credit for the inverse-square law of gravitation, and with virtually anyone who contradicted him on any subject. He died in London on March 31, 1727, at eighty-four, having never married, traveled abroad, or shown significant interest in any human relationship that did not involve an intellectual dispute. He left behind more transformed fields of knowledge than any single person in recorded history.