As a teenager, Newton’s mother took him out of school, hoping he would become a farmer. Fortunately, she was persuaded of his academic potential and at 18 he entered Cambridge University. There he quickly grasped what was known of science and moved on to his own independent research. Before he was 28 he developed theories that would revolutionize the world.
Newton’s life was greatly affected by the times he lived in. His father was killed in the Civil war fighting for the Charles I who, as mentioned, was beheaded. Then, when the Black Plague epidemic closed schools and universities, he had time to experiment on his own at his mother’s house in Woolsthorpe for 18 months.
By the time he was 22 Newton had read the works of all the important scientists and philosophers who preceded him, like Aristotle, Copernicus, Kepler, Descartes and Galileo. He described it later as “riding on the shoulders of giants.”
He discovered that ordinary white light is a mixture of all the colors of the rainbow and by 1668 had designed and built the first reflecting telescope for astronomic observation. As he thought about the world, he experimented, carefully recording his observations in a simple three step method: 1)Experiment; 2)Observe; 3)Record the results. (Now known as “The Scientific Method” that every first year science student is taught). He worked so long and hard, often without sleep for days that he became ill from exhaustion.
His early writing caused so much commotion that he stopped publishing and worked for 15 years out of the public eye. When he emerged, his findings would rock the scientific world. To the layman it is perhaps Newton’s explanation of gravity and how things move that is most meaningful.
In the 1500’s the theories of the ancient Greek, Aristotle, were still being taught. Aristotle had a notion of gravity (which meant “heaviness”). The more gravity an object had the more quickly it would fall to earth. According to the theory objects with little gravity like fire, sought the sky. Objects with great gravity like rocks sought the ground. This theory was accepted for thousands of years. Galileo, the great Italian who died the year Newton was born, proved that all objects no matter how heavy, (in the absence of wind resistance) fall at the same rate of speed.
Newton, always an inquisitive observer, had also noticed the strange force that seemed at work when swinging an object around the body — “centrifugal force.”
One day, so the story goes, while sitting in the garden he noticed an apple fall. There was nothing remarkable about that but he had been thinking about the moon and how it traveled around the earth. “If an apple falls to earth why doesn’t the moon fall, too. What keeps the moon in its path around the earth?”
He was suddenly struck by an amazing thought. Perhaps the moon was trying to fall to earth (a much larger mass than the moon). Perhaps there was some other force preventing it from doing so. What if the centrifugal force pulling the moon away from the earth was perfectly balanced with gravity force pulling the moon toward the earth? If that were true it might also account for the movement of the earth around the sun, in fact all the planets. How about the entire universe? Wow! What a concept. No wonder he couldn’t sleep.
Newton, still in his 20’s worked to develop the idea. Sure enough the theory held up. Larger masses attracted smaller masses. The sun 340,000 times larger that the earth’s mass was big enough to attract the earth and the other planets. Being an excellent mathematician, he used his own ‘calculus” to figure out the orbits of the heavenly bodies we can observe. Years later the Royal Society, through one of its members, Edmund Halley (Halley’s comet is named after this astronomer) asked Newton for his help.
Back in 1543, Nicholas Copernicus from Poland had told mankind that the sun, not the earth, was the center around which planets moved. In 1609 Johannes Kepler, a German astronomer, stated that the paths were oval, not circles, but he couldn’t prove it.
Traveling to Cambridge in the summer of 1684, Halley asked Newton how the orbit of the planets would look. Without hesitation Newton, who had kept his secret for years, replied “An ellipse, I have calculated it.” Halley was dumbfounded. Newton retrieved his notes and sent them to Halley. Deeply impressed, Halley insisted that Newton write down all his discoveries. He did this in a 250,000 word manuscript called “Principia” and finished with his best remembered Principles — the Three Laws of Motion including Law number three which states “To every action there is an equal and opposite reaction.”
With these laws Newton established a whole science of dynamics or mechanics which could explain the movement of almost everything. How tides work, how things move underwater, how to streamline boats, how a horse cart moves, how planets orbit the sun and much else.
In 1969 all his Laws of Motion came into play as the US launched the first manned rocket to the moon. Its jets exerted a force which met with an “equal and opposite reaction” from the air which in turn hurtled it upwards. It accelerated according to Newton’s second Law and at 190,000 miles up from the earth (two thirds of the way to the moon) the space ship started to speed up, as if it were going downhill. The astronauts had reached a point where the moon’s gravity was stronger than the earth’s. Newton’s equation had predicted that little fuel would be required for the return voyage because if they approached the moon along a route shaped like a figure eight, the moons’ gravitational pull would automatically sling the space ship around the moon and onto the return leg of the figure eight.
On July 20 at 3.18 PM Houston time as more than 600 million people watched, the lunar lander came to rest. A short while later Neil Armstrong took man’s first step on to the moon while the waiting lunar module orbited the moon according to Newton’s calculations 300 years before.
The world owes Newton a debt of gratitude for unlocking some of the mysteries of the universe. He was knighted Sir Isaac Newton and buried in 1727 at Westminster Abbey, the only scientist to be given that honor.
His 85 years on earth had been filled with marvelous discovery, but at the end of his life he modestly wrote:
“I seem to have been only like a boy playing on the seashore, 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.”
Because of its break with the Catholic Church, Britain had been somewhat removed from the advances in Arts and Science being made in Europe by the Renaissance but Newton’s brilliance had given new impetus to British creative thinking.
CLICK HERE FOR NEXT PAGE