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 centers.

For two objects of masses $m_1$ and $m_2$ and the distance between them $r$, the force $(F)$ of attraction acting between them is given by the universal law of gravitation as:

$F=\frac{G m_{1} m_{2}}{r^{2}}$

Where, $G$ is the universal gravitation constant and its value is $6.67 \times 10^{-11}\,Nm ^{2} kg ^{-2}$.