: a force manifested by acceleration toward each other of two free material particles or bodies or of radiant-energy quanta as if they were particles (as in the bending of rays of starlight passing close to the sun) : an attraction between two bodies that is proportional to the product of their masses, inversely proportional to the square of the distance between them, and independent of their chemical nature or physical state and of intervening matter
Universal force of attraction that acts between all bodies that have mass. Though it is the weakest of the four known forces, it shapes the structure and evolution of stars, galaxies, and the entire universe. The laws of gravity describe the trajectories of bodies in the solar system and the motion of objects on Earth, where all bodies experience a downward gravitational force exerted by Earth's mass, the force experienced as weight. Isaac Newton was the first to develop a quantitative theory of gravitation, holding that the force of attraction between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them. Albert Einstein proposed a whole new concept of gravitation, involving the four-dimensional continuum of space-time which is curved by the presence of matter. In his general theory of relativity, he showed that a body undergoing uniform acceleration is indistinguishable from one that is stationary in a gravitational field.