orbit. So the varying positions of the Laplace plane at varying distances from the primary planet can be pictured as putting together a warped or non-planar surface, which may be pictured as a series of concentric rings whose orientation in space is variable: the innermost rings are near the equatorial plane of rotation and oblateness of the planet, and the outermost rings near its solar orbital plane. Also, in some cases, larger satellites of a planet (such as Neptune's Triton) can affect the Laplace planes of smaller satellites orbiting the same planet. The work of Laplace The Laplace or Laplacean plane, as discussed here, relates to the orbit of a planetary satellite. It is to be distinguished from another and quite different plane, also discovered by Laplace, and which is also sometimes called the "Laplacian" or "Laplace plane", but more often the invariable plane (or the "invariable plane of Laplace"). The invariable plane is simply derived from the sum of angular momenta, and is "invariable" over the entire system, while the Laplace plane may be different for different orbiting objects within a system. Confusingly, a satellite's Laplace plane (as defined here) is also sometimes called its "invariable plane". The Laplace plane is a result of perturbational effects, which were discovered by Laplace while he was investigating the orbits of Jupiter's principal moons (the Galilean satellites of Jupiter, the only ones known in Laplace's time). Laplace found that the effects of the solar perturbing force, and of the planet's oblateness (its equatorial bulge), together gave rise to an "inclinaison propre", an "own inclination", in the plane of the satellite orbits, relative to the plane of Jupiter's equator. References Planetary science Orbits