What did isaac Newton do?

In June 1661, 18-year-old Isaac Newton left the family farm at Woolsthorpe and traveled to Cambridge, free at last to pursue his intellectual interests. During the next 3 years, he developed a passion for mathematics, mastering Descartes’ analytic geometry, Viète’s algebra and Oughtred’s Clavis (Key to Mathematics) in a rapid advance to the frontiers of mathematical knowledge.

In 1664–65, the bubonic plague was sweeping across England, wiping out about 100,000 people including almost 25% of London’s population. Cambridge University, where Newton was now enrolled as a student, was closed. Isaac returned to the farm where he continued to contemplate questions about the movements of the planets, the causes of the tides and the nature of light. During the period 1664 through 1666 known as his anni mirabiles (miracle years), Isaac made advances in the study of light, spawned calculus, conceptualized his laws of motion and universal gravitation, and in the process, laid the foundations of theoretical physics. However, it would take two decades of incubation for these insights to hatch into a coherent and polished form. Years later, reflecting on these anni mirabiles, he said, “In those days I was in the prime of my age for invention and minded mathematics and philosophy [physics] more than at any time since.”

Unfortunately, Newton’s solitary nature, together with an excessive sensitivity to criticism had made him reluctant to publish anything. In a letter on November 18, 1676 he asserted: 

I will resolutely bid adieu to it [further publication] except what I do for my private satisfaction, or leave to come out after me [after my death] for I see a man must either resolve to put out nothing new, or become a slave to defend it.

Consequently, by the time he reached 40 years of age, his work was relatively unknown to the scientific community. In 1684, astronomer Sir Edmond Halley (of comet fame) visited Cambridge to ask Newton whether it was possible to derive Kepler’s laws from some basic principles. Newton recalled that he had already done so, but hadn’t published it. At Halley’s request, Newton sketched his derivation of these laws in a paper titled On the Motion of Bodies in an Orbitin which he used differential calculus (originally called fluxions) that he had invented during his plague-enforced leave from Cambridge. Recognizing the importance of this discovery, Halley hounded and cajoled Newton to publish all his discoveries about planetary motion in a comprehensive work that Halley would fund. Finally, in 1687 Newton revealed these observations and derivations in a treatise titled, Philosophiæ Naturalis Principia Mathematica, known today as Principia. This treatise came to be regarded by scientists in the centuries that followed as perhaps, the greatest publication in the history of science.

In deducing Kepler’s Laws from basic axioms of physics, Newton’s formidable intellect moved science from an organized taxonomy of observed phenomena to a rigorous body of knowledge with predictive capability. In essence, Newton had developed the mathematics of rocket science almost three centuries before a rocket was sent to the moon. 

As copies of the Principia spread across the Channel to Europe, Newton moved from relative obscurity to demigod status. Revered as the ultimate authority in science, in 1696 at the age of 54, he was appointed Warden of the British Mint. In 1703, he was elected President of the Royal Society, and two years later, was knighted by Queen Anne. Sir Isaac Newton lived another 22 years, dying on March 27, 1727 in his eighty-fifth year, having received all the honors that could be bestowed on a human being. When praised for his remarkable achievements, he paid tribute to Descartes, Galileo, Copernicus, Kepler and others with the acknowledgement, “If I have seen further than others, it is by standing upon the shoulders of giants.” 

Though Newton was the pre-eminent mathematician and scientist of his time, he continued to challenge his assumptions. Never comfortable with his conception of gravitation as a force that acts at a distance, he wrote in a letter to theologian Richard Bentley in 1692: 

That one body may act upon another at a distance through a vacuum without the mediation of anything else, by and through which their action and force may be conveyed from one another, is to me so great an absurdity that, I believe, no man who has in philosophic matters a competent faculty of thinking could ever fall into it.

Historians of mathematics regard Isaac Newton as one of the top three mathematicians of all time–an auspicious group that includes Archimedes and Gauss.