But the problem is that the force is inversely proportional to the square of the distance. Can it be deduced that the orbit must be ellipse and satisfy Kepler's first law and second law? Most people suffer from poor mathematics and can't give a strict proof that "elliptical orbit motion is obtained by inverse square relationship". For example, Hooke, a famous British physicist, is Newton's opponent and has always dreamed of overthrowing Newton's theory. He claimed that he gave the proof that "the force is inversely proportional to the square of the distance", but he never published the proof process.
What he said alarmed Harley, so Harley ran to Hooke's house from time to time, but Hooke refused to take out his proof manuscript anyway. After a long time, Harley got bored. He thought Hook was bragging.
1684, Harley went to Cambridge to visit Hooke's opponent Newton. Newton said that he had proved the problem five years ago. Harley was so surprised that he soon claimed to contribute money to help Newton organize and publish the proof manuscript. Inspired by Harley, Newton, with high morale, cooperated with him. He immediately sorted out the manuscript of On Motion, and proved the gravitational inverse square law on an elliptical orbit by using Kepler's three laws, centripetal force law evolved from centrifugal force law, mathematical limit concept, calculus concept and geometric method.
1687, Newton officially published Mathematical Principles of Natural Philosophy with the support of Harley. This book brought great fame to Newton and established his position as "the first person in British science", and the whole picture of gravity was revealed for the first time in this book.
The pursuit of "mysterious power" by human beings for thousands of years is suddenly enlightened here, and all the credit will be attributed to Newton alone. Hook was unconvinced and asked Newton to mention his contribution at least in the preface of the book. After all, he does have the right to discover gravity. Hook published a paper on gravity in 1674, and wrote to Newton about the inverse law of gravity. Unexpectedly, Newton didn't care. On the contrary, when he returned home, he immediately deleted all references related to Hooke in the book. This tit-for-tat "gravity" dispute has therefore become a famous case-solving in the history of science.
But Hooke only put forward the conjecture about the gravitational relationship between the planet and the sun, and Newton can prove this conjecture with his calculus and extend the law of universal gravitation to all objects in the universe. In Newton's conjecture, the apple on the ground and the planet in the sky are subjected to the same force. Because the ratio of the centripetal acceleration of the moon in orbit to the acceleration of gravity on the ground is equal to the ratio of the square of radius of the earth to the square of the radius of the moon's orbit, namely 1/3600.
Now, we know that the gravity of the earth on the ground objects is the same as that on the moon. Newton unified the universe, so it is difficult for Hooke to achieve such a grand pattern.
Reading notes: every scientific theory is not perfect by one person, but the result of many people's efforts in this field. The pioneering work in the field of science is a breakthrough made by a person at the peak of intelligence, standing on the basis of previous research. Newton was such a man. He extended gravity to all celestial bodies in the universe in a grand pattern, and finally unveiled the true face of the mysterious force that has shrouded mankind for thousands of years. On the basis of modern science, there will be such leading figures in the future scientific development, opening up new scientific fields and pushing science and technology to a higher peak. Maybe we can go to the universe in our lifetime.