Newton’s law of gravitation Everybody in the universe attracts every other body that is directly proportional to product of their masses m₁, m₂ and inversely proportional to the square of distance, r between them.

F = G (m₁ m₂ /r) r

where r is a unit vector in the direction of r and G is constant called the universal gravitational constant. The value of G is 6.67´ 10^-11 N.m².kg^-2.