How to use in-sentence of “invariable”:
+ The invariable plane is within 0.5° of the orbital plane of Jupiter.
+ It is almost invariable over the entire system.
+ The ecliptic plane should be distinguished from the invariable plane.
+ For almost all purposes the plane can be considered invariable when working in {Newtonian dynamics.
+ The invariable plane is got from the sum of angular momenta.
+ Sometimes the invariable plane is used instead.
+ The invariable plane of a planetary system is the plane passing through its barycenter.
+ The inclination of the Earth’s orbit has a 100,000 year cycle relative to the invariable plane.
