Gravitational potential energy (http://hyperphysics.phy-astr.gsu.edu/hbase/pegrav.html#pe) is energy (http://hyperphysics.phy-astr.gsu.edu/hbase/conser.html#coneng) an object possesses because of its position in a gravitational field. The most common use of gravitational potential energy is for an object near the surface of the Earth where the gravitational acceleration can be assumed to be constant at about 9.8 m/s ² .

The general expression for gravitational potential energy arises from the law of gravity (http://hyperphysics.phy-astr.gsu.edu/hbase/grav.html#grav) and is equal to the work done against gravity to bring a mass to a given point in space. Because of the inverse square  (http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html#isqg) nature of the gravity force, the force approaches zero for large distances, and it makes sense to choose the zero of gravitational potential energy (http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/gravpe.html#c1) at an infinite distance away.

U = -GmM/r