Gravity

The first modern, scientifically successful explanation of gravity was proposed by Sir Isaac Newton. By the conventional (Newtonian) theory, gravity is a somewhat understood force, which is demonstrated when large, massive objects attract each other. The greater the mass, the greater the attraction.

Conventional theories of gravity sum-up the total behavior of gravity as if it emanated from a single point at the center of a mass. For an example, at the surface of the earth, gravity behaves as if the entire interaction originated at the center of our Earth. All other gravitational interactions in the universe are assumed to agree with the standard of reference, compared to the supposed to behave in a similar fashion.

By conventional theory, the "force" of gravity is proportional to the mass of the two (or more) objects in consideration. If either mass is doubled, then the force increases by a double amount. If the distance between the masses is doubled, the attractive force of gravity is one fourth of the previous amount.

In Newton's theory, at a distance, the force of gravity is supposed to behave as if the entire gravitational force emanated from a point at the exact center of each mass under consideration. The force could be calculated from the size of the two masses, and the distance between their centers. In addition, the force of gravity is defined by a gravitational constant, g, which would be multiplied by the two masses, and divided by the distance squared, to obtain the value of gravity in some standard, measurable units.