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 essence of spirit, he thought to himself, was to choose the thing which did not better one’s position but made it more perilous. That was why the world he knew was poor, for it insisted morality and caution were identical.”
—Norman Mailer (b. 1923)
“Being in a family is like being in a play. Each birth order position is like a different part in a play, with distinct and separate characteristics for each part. Therefore, if one sibling has already filled a part, such as the good child, other siblings may feel they have to find other parts to play, such as rebellious child, academic child, athletic child, social child, and so on.”
—Jane Nelson (20th century)
“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)