Isaac Newton’s Law of Gravity

“Sir Isaac Newton, born in 1641, may be the greatest scientist who ever lived”

Newton conceived of a formula, a law of motion, that described the mysterious attractive force that affects how all matter in the universe works.

Copernicus proposed a sun-centered universe.

Galileo observed it in his telescope, but Newton explained the clockworks that put it all in motion.

He called it… gravity.

Newton believed that the universe was a clock – a gigantic clock – a machine, that God wound up at the beginning of time and has been ticking ever since due to his laws of motion.

Newtown’s Gravity Brilliantly Merged Theories of Galileo and Kepler

Newtown’s Gravity offered a single explanation for two seemingly unrelated phenomena.

  • Kepler had years before observed the strange hold the sun seemed to have on the planets that encircled it. They sped up the closer they came to the sun.
  • Galileo had demonstrated that on earth, falling bodies that no matter what their mass, always fall at the same rate.

The great insight Newton had was to bring Galileo and Kepler together and to realize that the things that make projectiles move and fall at the same speed here on Earth, is the same thing that makes planets go around the sun in the skies.

This revolutionary insight reportedly occurred to Newton during an innocent stroll through his estate in the evening. He saw an apple fall. Then he saw the moon. And then he asked the key question: “If an apple falls to the Earth, does the Moon also fall?”

Then, in a flash of insight, Newton realized that the Moon is falling around the Earth. The same forces that govern an apple, govern the Moon. The moon is in freefall around the Earth. The Earth is in freefall around the Sun.

So Newton showed that even the Universe is subject to the same law that makes an apple fall.

A Powerful Law With An Unsolved Mystery…

Newtown’s laws have explained almost everything. Newtown’s laws were a fundamental language of the Universe.

And so, physics really began with Isaac Newton.

In his great book the Principia, he uses observation and mathematical formulai to predict the orderly phenomena of nature, including gravity. Newton saw gravity like a tether invisibly connecting objects. But what it doesn’t do, what Newton never did was explain what gravity actually was.

He himself was troubled by the fact that he didn’t know how the influence was traveling from one object to another. There’s no rope between them, there’s no hand reaching out from one to the other. So how is it that say, the Sun is affecting the motion of the Earth. How does gravity get the job done?

Newton said, “I don’t know”.

Whether or not he could explain what exactly gravity was, Newton’s laws of motion worked. They did then, they do now… and they will… a billion years from now.