noun, plural grav·i·ties.
Origin of gravity
Synonyms for gravity
noun plural -ties
Word Origin for gravity
c.1500, "weight, dignity, seriousness," from Middle French gravité "seriousness, thoughtfulness," and directly from Latin gravitatem (nominative gravitas) "weight, heaviness, pressure," from gravis "heavy" (see grave (adj.)). The scientific sense of "force that gives weight to objects" first recorded 1640s.
A Closer Look: With his law of universal gravitation, Sir Isaac Newton described gravity as the mutual attraction between any two bodies in the universe. He developed an equation describing an instantaneous gravitational effect that any two objects, no matter how far apart or how small, exert on each other. These effects diminish as the distance between the objects gets larger and as the masses of the objects get smaller. His theory explained both the trajectory of a falling apple and the motion of the planets-hitherto completely unconnected phenomena-using the same equations. Albert Einstein developed the first revision of these ideas. Einstein needed to extend his theory of Special Relativity to be able to understand cases in which bodies were subject to forces and acceleration, as in the case of gravity. According to Special Relativity, however, the instantaneous gravitational effects in Newton's theory would not be possible, for to act instantaneously, gravity would have to travel at infinite velocities, faster than the speed of light, the upper limit of velocity in Special Relativity. To overcome these inconsistencies, Einstein developed the theory of General Relativity, which connected gravity, mass, and acceleration in a new manner. Imagine, he said, an astronaut standing in a stationary rocket on the Earth. Because of the Earth's gravity, his feet are pressed against the rocket's floor with a force equal to his weight. Now imagine him in the same rocket, this time accelerating in outer space, far from any significant gravity. The accelerating rocket pushing against his feet creates a force indistinguishable from that of a gravitational field. Developing this principle of equivalence, Einstein showed that mass itself forms curves in space and time and that the effects of gravity are related to the trajectories taken by objects-even objects without mass, such as light. Whether gravity can be united with the other fundamental forces understood in quantum mechanics remains unclear.
Another term for gravitation, especially as it affects objects near the surface of the Earth.