The gravitational constant G is a key quantity in Newton's law of universal gravitation

The gravitational constant, called \displaystyle{ G } in physics equations, is an empirical physical constant. It is used to show the force between two objects caused by gravity. The gravitational constant appears in Isaac Newton's universal law of gravitation.

\displaystyle{ G } is about 6.67430×10⁻¹¹ N⋅m²/kg², and is denoted by letter \displaystyle{ G }. In the SI system, the constant is equal to the force in newtons that two objects, each with a mass of 1 kilogram, exert on each other at a distance of 1 meter.