The direction of a gravitational field at a point within the field. In the vicinity of a massive body such as a star or planet, the gravity gradient points to the body's centre. An elongated object in orbit about the body will revolve with its long axis pointing towards the body's centre. For example, the Moon's longest axis lies along a line towards the Earth's centre. Artificial satellites can be oriented in orbit by making use of the gravity gradient.
Subjects: Astronomy and Astrophysics.