Derivation of the law of universal gravitation (detailed) More detailed, the best picture!

Derivation of the law of universal gravitation (detailed) More detailed, the best picture!

The law of universal gravitation is indeed "guessed". It is a strict mathematical conclusion to deduce that the gravitation between the sun and the earth satisfies f = GMM / R ^ 2 from Kepler's third law, but it does not mean that there is such gravitation between objects with mass