Isaac Newton

From Citizendium
Revision as of 07:15, 9 November 2007 by imported>Olier Raby (Edited. Layout.)
Jump to navigation Jump to search

Sir Isaac Newton (Woolsthorpe 1642 - London 1727) is one of the giants in the history of science. He laid the foundations of differential and integral calculus and classical mechanics—often referred to as "Newtonian mechanics". The year 1666 is known as Newton's annus mirabilis (miraculous year). As a Cambridge student fleeing the bubonic plague, he temporarily stayed at his mother's home and, seeing an apple fall from a tree, discovered the law of gravitation (attraction is proportional with one over distance squared). It seems that he associated the fall of the apple with the motion of the moon. The same year he discovered the rudiments of differential and integral calculus.

Later he worked this out into a set of mechanical laws, with his second and most important law: force is mass times acceleration (). Newton was the first to understand the concept of inertial forces, notably the centrifugal force. In 1684 Newton proved that Kepler's laws follow from his second mechanical law in conjunction with his gravitational law. This proof completed the astronomical revolution initiated by Copernicus.

Newton hated publishing his results, prefering to communicate them to close colleagues. It took Edmond Halley great efforts to convince Newton to write his opus magnum Philosophiae Naturalis Principia Mathematica (briefly the Principia) that appeared in 1687, a work on mechanics, not on calculus. Although Newton had communicated his discoveries in the calculus privately, he had not published anything formal about it, until finally in 1704 he published Opticks. In the meantime the German mathematician and philosopher Gottfried Wilhelm Leibniz had developed his own version of the calculus. Although he acknowledged that Newton was earlier, a nasty priority conflict broke out in the 1690s. Newton and his (mainly English) followers accused Leibniz of plagiarism. The modern view is that both scientists discovered the calculus independently.

Later in life Newton became master of the Mint, and received in 1705 a knighthood because of his valuable work on the English money reform.