He changed the way we view ourselves, our world, the universe itself. On this day, we celebrate the birth of possibly the greatest intellect of all time: Isaac Newton. He was born 362 years ago in the manor house of Woolsthorpe, near Grantham in Lincolnshire. It is shocking how few realize what he did. When asked what Newton’s achievement was, most people reply, “He discovered gravity.” When pressed to say what exactly that means (after all, people had known that things fall down, not up, for quite some time), many will say, “Well, he quantified gravity.” When told about Galileo’s laws, and how we knew quite a bit (quantitatively) about how gravity affects objects well before Newton, most people become confused. But when told about Kepler and his laws of planetary motion, and how Newton realized that they and Galileo’s discoveries about balls rolling down inclined planes could be explained in one fell swoop using a couple of equations, and shown to be the result of the same phenomenon (gravity), they are usually and finally suitably impressed. Hence, Newton connected what was known about the heavens (Kepler’s Laws) with what was known about earth (Galileo’s Laws). This stupendously imaginative act of integration is what encouraged Einstein to do the same with the electromagnetic theory of Maxwell, and the experimental results of Michaelson and Morley regarding the speed of light. And it is what keeps physicists today hopeful about one day discovering the one true Theory Of Everything.
To celebrate Sir Isaac’s birthday, give yourself a gift, and read S. Chandrasekhar’s (yes, Nobel, physics) Newton’s “Principia” for the Common Reader:
Representing a decade’s work from one of the world’s most distinguished physicists, this major publication is, as far as is known, the first comprehensive analysis of Newton’s Principia without recourse to secondary sources. Chandrasekhar analyses some 150 propositions which form a direct chain leading to Newton’s formulation of his universal law of gravitation. In each case, Newton’s proofs are arranged in a linear sequence of equations and arguments, avoiding the need to unravel the necessarily convoluted style of Newton’s connected prose. In almost every case, a modern version of the proofs is given to bring into sharp focus the beauty, clarity, and breathtaking economy of Newton’s methods. Chandrasehkar’s work is an attempt by a distinguished practising scientist to read and comprehend the enormous intellectual achievement of the Principia.
Buy it here or elsewhere.