b. 25 December 1624
d. 20 March 1727
Noteworthies:
- Authored Principia, defining the basic laws of motion
- Invented calculus
- Lucasian Professor of Mathematics at Cambridge
Newton was supremely inquisitive. Even as a child he was extremely curious about his surroundings. He drew pictures, invented tools and appliances, experimented, and was eternally posing questions to himself. Interestingly, he was totally apathetic to school and performed terribly. But either the prospect of having to manage the family estate or an alleged attack from an elementary school bully changed his mind and he eventually got accepted to Cambridge. There, he worked his way through school waiting tables and doing janitorial work until he was accepted on scholarship.
In 1665, the campus was closed for 18 months due to an outbreak of the bubonic plague. Oddly, the year and a half he spent at home was Newton's self-termed annus mirabilis (miraculous year), during which his scientific career exploded. While at home he invented calculus and began solving previously unsolvable problems with apparent ease.
Calculus can be termed as the study of infinitesimal progression. Take a falling ball, for example. Imagine that you took a picture of it one time every second until it hit the ground. Developing the pictures, you could analyze how far the ball fell each second and would probably be able to determine that the ball fell more at the end of its flight than at the beginning. Now imagine that you took a picture of the ball every tenth of a second. Suddenly, you might be able to calculate exactly how much further the ball has fallen in each successive shot (think of making a flip book out of each set of pictures, the one-second pictures would depict a ball with very choppy movement, whereas the other set would show a much smoother trajectory). As the time between successive pictures decreases, so also does the accuracy of our measurement for any given period of time. If it were possible that there was an infinitely small separation between one instant and the next, we would know as much as was possible to know about the falling ball.
This is effectively the concept of calculus. Newton developed a way to take infinitesimally small "pictures" of mathematical situations and was thus able to analyze every single instant from the start of an action to its finish. He developed the idea during what was effectively an overly long summer break. It became an enormously powerful tool.
Another scientist named Robert Hooke once proved a hypothesis made by Kepler that planets travelled in elliptical orbits but refused to share it with his coworkers presumably to avoid having to credit them. The coworkers consulted Newton who replied that he had solved the problem four years prior and simply threw it aside and eventually lost it. He then spent 18 months working furiously to publish before Hooke, at which he succeeded.
Here we encounter another one of Newton's more colorful personality traits: ego. It was perhaps his towering pride that led to his most influential discoveries. Frequently his books were published out of spite for another scientist. Any derogatory remark made about him or his work threw him into a black depression that could only be cured by besting the man who made the comment. As a final blow to his then lifelong enemy, Newton even refused to publish his groundbreaking discoveries in the field of optics until Hooke was dead, thus never revealing to him what had been discovered.
Among the body of scientists at the time, problems were frequently shared so as to facilitate their discovery. Johann Bernoulli once posed the problem of the curves of quickest descent (the Brachistochrone curve), which is the path an object must take between two points that causes it to get there the fastest (hint: it is not a straight line unless one point is directly above the other). Only a few responded, one (Newton) anonymously, as if to say that anyone could solve it. But when Bernoulli read the nameless proof he immediately named Newton as the author proclaiming, "Ah! I know the lion by its paw."
Among other publications, Newton wrote a book known as The Mathematical Principles of Natural Philosophy or Principia for short. It outlines the basic laws governing motion and forces and defines the basic terms that we now consider commonplace (force, mass, velocity, acceleration, inertia, etc.). He proved that all masses are acted upon by gravity in the same way (the moon and an apple, for example), and most importantly, gave us the mathematical tools to solve basically every problem with perfect (yes, perfect) accuracy given the correct conditions. Still, of his own accomplishments, he said, "I do not know how I may appear to the world, but to myself I seem to have been only like a boy, playing on the sea-shore, and diverting myself, in now and then finding a smoother pebble or prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
