**39. Discovery Of Gravity & Detection Of Gravitational Waves**

**Discovered By:***Archimedes, Galileo Galilei, Isaac Newton (Gravity) & Henri Poincaré (G-Waves)*

The explanation of how gravity worked first came from Greek Scientist Archimedes, who discovered the center of gravity of a triangle. Galileo Galilei then worked on his concept, finding out how gravitational acceleration was the same for all objects. He also found that air resistance was likely why some objects fell slower than others. Isaac Newton then came along and found out the inverse-square law of universal gravitation.

This mostly had to do with planets and moons and what separates them. He came up with the gravitational constant formula where F is the force, M1 & M2 are the masses of the interacting objects, and R is the distance between the centers of the masses. Then in 1905, it was Henri Poincaré who proposed the theory of gravitational waves. These are curvatures of spacetime, made by accelerated masses, that operate as waves outward from their source all at the speed of light.