Astrophysics (Index)About


(oscillating motion of orbiting bodies relative to each other)

Libration is relative oscillating motion between two orbiting bodies. A common use of the term is in describing the Moon's rocking motion as viewed from Earth. It is also used for similar situations with other orbiting bodies and disks (e.g., circumstellar disks) and other situations where there is such an oscillation.

The Moon, as viewed from a point on Earth shows four kinds of libration:

A study of Enceladus's physical libration has claimed evidence of a disconnection between its surface and much of its mass, implying a global ocean under its ice.

Lagrangian points, are also known as libration points. I imagine this is because an object can reside in a small orbit around a stable Lagrangian point, the small orbit constituting an oscillation within its movement around the larger body.

Further reading:

Referenced by pages:
Lagrangian point