Phenomenon/Gravity

Gravity
Gravity (Force, Physics, Theory):

The Newtonian theory of gravity is based on an assumed force acting between all pairs of bodies—i.e., an action at a distance. When a mass moves, the force acting on other masses had been considered to adjust instantaneously to the new location of the displaced mass. That, however, is inconsistent with special relativity, which is based on the axiom that all knowledge of distant events comes from electromagnetic signals.

In Einstein’s theory of special relativity, inertial mass is a manifestation of all the forms of energy in a body, according to his fundamental relationship E = mc2, E being the total energy content of a body, m the inertial mass of the body, and c the speed of light. Dealing with gravitation, then, as a field phenomenon, the weak principle of equivalence indicates that all forms of nongravitational energy must identically couple to or interact with the gravitational field, because the various materials in nature possess different fractional amounts of nuclear, electrical, magnetic, and kinetic energies, yet they accelerate at identical rates.

Newton's law of universal gravitation
The equation for universal gravitation thus takes the form:



Where F is the gravitational force acting between two objects, m1 and m2 are the masses of the objects, r is the distance between the enters of their masse], and G is the gravitational constant.