The year Galileo died, Isaac Newton was born. According to the Julian calendar in use in England at the time, Newton was born on Christmas Day 1642. But by the 1640s, much of the rest of Europe was using the Gregorian calendar (the one in general use today); according to this calendar, Newton was born on Jan. 4, 1643.
Nevertheless, Newton’s legacy is such a gift it seems appropriate to go with the Christmas date. It is difficult to explain all the ways in which the intellectual products of this brilliant scientist were critical to the scientific development of mankind. Newton singlehandedly contributed more to the development of science than any other individual in history. Some of his achievements are delineated below.
* In Principia Mathematica (1687), Newton laid out the three laws of motion now known as Newton’s laws (laws of inertia, action and reaction, and acceleration proportional to force).
* Newton invented, designed, and constructed a reflecting telescope. He ground the mirror, built the tube, and even made his own tools for the job.
* He formulated mathematical explanations for tides and lunar motion and correctly predicted the return of Halley’s Comet.
* Newton correctly solved the first ever problem in the calculus of variations and in fact invented calculus years before Leibniz. (However, he did not publish his work on calculus until afterward Leibniz had published his.)
* Newton invented a revolutionary scientific method of concise and universal rules for investigation.
* Newton formulated the classical theories of mechanics and optics.
* Newton was the first to observe that white light could be separated by a prism into a spectrum of different colors.
* Newton formulated a system of chemistry that included “elements” consisting of different arrangements of atoms, and atoms consisting of small, hard, billiard ball-like particles. He explained chemical reactions in terms of the chemical affinities of the participating substances.

Elucidation of the motion of projectiles
Alexander Pope’s couplet about Newton says it all: “Nature and Nature’s laws lay hid in night; God said, Let Newton be! and all was light.”