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Ancient Greeks
Aristotle believed that there is no effect or motion without a cause.Aristotle's system heavy bodies are not attracted to the earth by an external force of gravity, but tend toward the center of the universe because of an inner gravitas or heaviness. -
Newton
In his own words, “I deduced that the forces which keep the planets in their orbs must be reciprocally as the squares of their distances from the centers about which they revolve; and thereby compared the force requisite to keep the Moon in her orb with the force of gravity at the surface of the Earth; and found them answer pretty nearly.” Newton had a formula for gravity but it all started when he observed an apple falling from a tree and he began to think of how it is that gravity reached.... -
Einstein
Einstein proposed that spacetime is curved by matter, and that free-falling objects are moving along locally straight paths in curved spacetime. . More specifically, Einstein discovered the field equations of general relativity, which relate the presence of matter and the curvature of spacetime and are named after him. The Einstein field equations are a set of 10 simultaneous, non-linear, differential equations. -
Cavendish
Cavendish agreed an reinforced the formula that Newton had come up with and it was actually him who determined what the big ''G'' actually was. Without his contribution, Newtons formula would be incomplete.