Newton's Principia and the New Cosmic Order

Isaac Newton (1642–1727) published his Philosophiae Naturalis Principia Mathematica ("Mathematical Principles of Natural Philosophy") in 1687, with funding and encouragement from the astronomer Edmond Halley, who had approached Newton, then Lucasian Professor of Mathematics at Cambridge, after Newton privately claimed already to have proven that an inverse-square law of gravitational attraction would produce elliptical planetary orbits of the kind Kepler had described empirically decades earlier. The Principia, written in Latin in a rigorously geometric style modeled on Euclid, set out three laws of motion — the law of inertia (a body remains at rest or in uniform straight-line motion unless acted on by a force), the law relating force to the rate of change of momentum (commonly rendered F = ma), and the law that every action has an equal and opposite reaction — together with the law of universal gravitation, according to which every particle of matter in the universe attracts every other particle with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.