He formulated the Law of Universal Gravitation, which states that every particle of matter in the universe attracts every other particle with a force that is:

* Proportional to the product of their masses (meaning heavier objects exert a stronger gravitational pull).

* Inversely proportional to the square of the distance between their centers. (meaning the farther apart objects are, the weaker the gravitational force).

This discovery explained why objects fall to the ground, why the moon orbits the Earth, and why planets orbit the Sun. It is a fundamental force that governs the motion of everything in the universe, from the smallest particles to the largest galaxies.