Talk:Invariable plane

From Wikipedia, the free encyclopedia

[edit] Orbital axes ?

I don't understand your phrase "the rotational axes are not parallel to the orbital axes" (3rd para.). It seems to make no sense. Do you perhaps mean "orbital planes" ? Kiwi137 12:12, 23 April 2007 (UTC)

The rotational axis of a planet is its spin axis, around which it rotates. Earth's rotational period is 24 hours. The orbital axis of a planet is a line perpendicular to its orbital plane, passing through the center of mass of the solar system, around which it revolves. Earth's orbital period is 365¼ days. Earth's rotational axis is tilted 23.5° to its orbital axis, which causes the seasons. Thus Earth's rotational axis is not parallel to its orbital axis. — Joe Kress 20:14, 23 April 2007 (UTC)

Thanks Joe, that makes it much clearer. I can follow the reasoning in the article now.--Kiwi137 21:45, 24 April 2007 (UTC)

[edit] Couple of questions

1) What is the inclination of the invariable plane with respect to a) the galactic plane; and b) the ecliptic? 2) The article says that the barycenter moves over time. Does the plane's inclination change as well? (The article only says that the orbital planes for the planets fluctuate.) SharkD (talk) 02:11, 15 February 2008 (UTC)