Position
All planetary orbital planes wobble around the invariable plane, meaning that they rotate around its axis while their inclinations to it vary, both of which are caused by the gravitational perturbation of the other planets. That of Earth rotates with a quasi-period of 100,000 years and an inclination that varies from 0.1° to 3°. If long-term calculations are performed relative to the present ecliptic, which is inclined to the invariable plane by about 1.5°, it appears to rotate with a period of 70,000 years and an inclination that varies between 0° and 4°. Specifically, Earth's orbit (the ecliptic) is inclined to the invariable plane by 1°34'59"−18"T, where T is the number of centuries since 1900. Its J2000.0 value is 1°34'43.3". The inclination of the orbit of Jupiter to the invariable plane varies over the range of 14'–28'.
Read more about this topic: Invariable Plane
Famous quotes containing the word position:
“Only the other day I was inquiring of an entire bed of old- fashioned roses, forced to listen to my ramblings on the meaning of the universe as I sat cross-legged in the lotus position in front of them.”
—Prince Charles (b. 1948)
“The Americans are violently oral.... That’s why in America the mother is all-important and the father has no position at all—isn’t respected in the least. Even the American passion for laxatives can be explained as an oral manifestation. They want to get rid of any unpleasantness taken in through the mouth.”
—W.H. (Wystan Hugh)
“Journalism without a moral position is impossible. Every journalist is a moralist. It’s absolutely unavoidable. A journalist is someone who looks at the world and the way it works, someone who takes a close look at things every day and reports what she sees, someone who represents the world, the event, for others. She cannot do her work without judging what she sees.”
—Marguerite Duras (b. 1914)