Birth of Physics and Newton’s Apple -1

Newton and the aloe: it’s an image as enduring as any in history. As the story goes, the 23 year old Isaac Newton was sitting in his garden in his home in woolsthorpe, England, when he noticed an apple fall to the ground. A moment’s pondering, and he was inspired to postulate the law of universal gravitation.

Newton himself never put this story in writing, though he did recount it to his friend and biographer, William Stukeley, one evening in 1726, one evening in 1726. Yet, two other biographers of Sir Isaac his physician Henry Pemberton and mathematician William Whiston- interviewed Newton extensively about the origins of his theory of gravity, and neither mentioned the apple.

The story comes to us through Voltaire, who recounted it in Elements de philosophie de Newton, claiming he had heard it from Newton’s niece, Catherine Barton Conduit, who lived with Newton and managed his house hold for 20 years. Some historians speculate that Catherine may have been telling the truth- but she mistook an example her uncle had used to explain gravity for an actual occurrence. Carl Friedrich Gauss, the great 19th century mathematician, dismissed the entire story as an absurd insult to Newton’s genius.

 Whether or not the story is true, the impression it leaves- that Newton formulated his theory in isolation- is certainly misleading. In the late 1670s, Newton was already famous for his theories about light, his experiments in optics, his formulation of calculus and his invention of the reflection telescope. He climbed the academic fame quickly but found himself enrolled in several disputes over who had thought of what scientific theory first. Newton had little patience for such squabbling and resigned from the Royal Society, calling science ”a litigious lady.”

But then, in 1679, one of Newton’s earlier rivals, Robert Hooke, became secretary of the society. Hooke was stymied by several problems in mechanics and believed Newton was the only man who could help. So in November of the year, Hooke wrote a gracious letter to Newton inviting him to correspond on subjects in physics of mutual interest. Newton accepted the invitation, but soon regretted doing so, And the reason? Hook made public some of Newton’s erroneous speculations, much to Newton’s embracement.

 It was in one of Hooke’s letters, however, that Newton first heard the idea that the motion of an object under the influence of a force could be broken up into to composite motions; one I the direction of the force and changing in accordance with Newton’s second law and the other perpendicular to the force and moving uniformly in accordance with the Newton’s first law. Unbeknownst to Hooke, this was the breakthrough idea that Newton needed.

                                      (Cont.)