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do all the planets spin in the same direction? sorry for the last one, hadnt read the conservation of angular momentum bit.
Earth's spin axis is tilted at about 22 degrees with respect to
the ecliptic plane, but the spin and orbital angular momentum point 22
degrees from each other (and not almost opposite). Most planets follow
this, with their spin axis pointing perpendicular to the orbital plane.
But Uranaus is a standout. Its spin axis is about 90 degrees off, which
means its spin axis lies almost in its orbital plane.
(republished on 07/19/06)
Follow-Up #1: The shape of planetary orbits
The overall shape of the orbits of most of the planets in the solar system is what?
In the old-old days there were a variety of incorrect ideas about the shapes of planetary orbits. A breakthrough came in the early 17th
century when Johanes Kepler, using astronomic data supplied by Tycho Brahe, figured out that the orbits were oval shaped ellipses. Later on Newton derived the correct elliptical shape using the laws of motion he had developed along with the hypothesis that the force of gravity between two objects fell as 1/r2
, where r is the distance between them. In the 20th
century Einstein developed very small corrections to the elliptical orbits using the general theory of relativity.
See: http://en.wikipedia.org/wiki/Tycho_Brahe http://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion
for more more formation.
(published on 06/09/09)
Follow-up on this answer.