gravitational constant

The gravitational constant, approximately and denoted by the letter , is an empirical physical constant involved in the calculation(s) of gravitational force between two bodies. It usually appears in Sir Isaac Newton's law of universal gravitation, and in Albert Einstein's general theory of relativity. It is also known as the universal gravitational constant, Newton's constant, and colloquially as Big G. It should not be confused with "small g" , which is the local gravitational field of Earth (equivalent to the free-fall acceleration).