The universal law of gravitation states that every object in the universe attracts every other object with a force called the gravitational force. The force acting between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.
For two objects of masses, m1and m2 and the distance between them r, the force (F) of attraction acting between them is given by the universal law of gravitation as:
F = (Gm_1 m_2)/r^2
Where G is the universal gravitation constant
G = 6.67×10^(-11) Nm^2 kg^(-2).