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:
“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)
“People who are in a fortunate position always attribute virtue to what makes them so happy.”
—John Kenneth Galbraith (b. 1908)
“They who say that women do not desire the right of suffrage, that they prefer masculine domination to self-government, falsify every page of history, every fact in human experience. It has taken the whole power of the civil and canon law to hold woman in the subordinate position which it is said she willingly accepts.”
—Elizabeth Cady Stanton (1815–1902)