By Dan Hooper Ph.D., University of Chicago
Isaac Newton was a scientist and a philosopher. His three laws and the concept of gravity were among the most important scientific achievements of all time. However, being a philosopher sometimes overshadowed his scientific side and led to scientific mistakes. What were the mistakes made by the smartest man ever?
Newton’s Principia
Isaac Newton’s collection of contributions to science can be found in his book Mathematical Principles of Natural Philosophy, called for short Principia. Published in 1687, the book described the basics of physics, including the law of universal gravitation and Newton’s three laws of motion.
Newton based his three laws on Kepler’s three laws of motion. He showed that the planets move the way they do because of gravity. He had numerous accomplishments, but a few of the more significant ones include substantial contributions to the science of light, sound, and heat, and the invention of calculus. Gottfried Leibniz also invented calculus independently, around the same time. However, Newton also made a mistake.
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Newton and the Planets
In a similar way to Galileo and Kepler, Newton’s mistake lies in the solar system and the motion of the planets. Even though Galileo and Kepler were some decades earlier than Newton, he still made a mistake in the same area.
In Principia, laws and equations to describe the motion of the planets, moons, and comets in the solar system are gathered. It took about 200 years until Einstein revised the principle with the theory of general relativity. However, just having the tools was not enough to calculate the complex motions of planets because each planet is affected by a variety of gravitational forces from different planets and astronomical bodies.
Newton knew that the Sun’s gravity was much stronger than that of the planets, yet he worried that the planet gravities could not be ignored. He thought sometimes one planet could pull another out of its orbit and throw it toward the Sun or another planet, or even out of the solar system.
This is a transcript from the video series What Einstein Got Wrong. Watch it now, on Wondrium.
Newton and His Belief in Miracles
Following the forces in the solar system, Newton asked himself, “If planetary orbits are so unstable, why are there still so many planets orbiting the Sun?” He answered the question with a philosophical concept: God. He believed that the planets and their motion obeyed the laws of motion, but sometimes they would be thrown out of orbit due to other gravitational forces. That was when God would take the planet and put it back in place.
Leibniz reacted to this theory by declining God’s intervention and miracles in the solar system. However, not many would have refused to accept God as an influential force. The ‘God of the gaps’ was used widely by many theists, over centuries, to give absolute answers to questions they had no scientific answer to. The further science evolved, the less the tendency to put God in blanks became.
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Pierre-Simon Laplace Answered Newton’s Question
Around 100 years after the Principia was published, the French mathematician Pierre-Simon Laplace answered Newton’s question of how planets do not get thrown out of the solar system. He showed with mathematical rigor that the solar system is stable over very long periods and that the planetary orbits were stable indefinitely.
There is a story, maybe not all true, that Laplace gave a copy of his book to his friend, Napoleon Bonaparte. Napoleon asked him about the role of God in keeping the solar system order, and Laplace replied, “I have no need of that hypothesis.”
The more science learns about the natural phenomena at different scales, the more the role of God and miracles lose importance. Many of the blanks that theists had put God in as an answer were later filled with mathematics or physics. Newton was undoubtedly one of the greatest scientists and most influential figures of all time, but the influence of the environment was still strong on him.
Common Questions about Isaac Newton
One of the main discoveries of Isaac Newton was how gravity functions and the effects it has on our world. His other significant scientific contribution was the three laws of motion, which were in line with Kepler’s three laws of planetary motion.
Isaac Newton’s collection of contributions to science can be found in his book Mathematical Principles of Natural Philosophy, called for short Principia.
Albert Einstein once said that Isaac Newton was the smartest person who ever lived. However, this does not mean he was a perfect person with no mistakes. Even though his three laws of motion and gravity were right, he tended to put God in scientific blanks that he had no explanation for.
