Newton's Law of Gravity states that attrative force (gravity) exists between any two objects. The formula is:
  F = G * m1 * m2 / d²
Where:
F: Gravitational Force, in N
m1: Mass of Object 1, in Kg
m2: Mass of Object 2, in Kg
d: Distance between the two Objects, in m
G: Gravitation Constant, is 6.67 × 10^-11 N.m²/kg²