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Planets and Moon Orbit

  1. Feb 11, 2008 #1
    Uranus, Neptune, Jupiter, Mars, Pluto, etc.--each of them has either moons or rings. Both rings and moons revolve around their equators regardless of the planets' axis. What concerns me is that while Earth's moon also revolves around the axis of Earth, why is it that during the saros, the moon has gradually switched ascending and descending nodes? Doesn't the moon's revolutionary path become perpendicular to Earth's axis instead of parallel with it? It seems very contradictory to any other moon or ring.

    Given that, what I want to know, is it possible for a perfectly upright planet with no axis to have a moon that revolves on an axis anyway? Or, moons that don't necessarily revolve evenly along a planet's equator, above or below it? I mean, if you look at Pluto, it revolves around the sun on an axis, whereas the other planets revolve along the sun's center. Can the same apply to moons or rings? Would that be possible if the planet grabbed materials in its gravitational field at an angle, formed a moon that way, and it just happens to revolve at the eccentric angle the planet grabbed it from?
  2. jcsd
  3. Feb 11, 2008 #2


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    The Moon's orbit is about 1/3 of the way to the edge of Earth's Hill sphere. This is very far compared to the other major moons in the solar system. Consequently, the perturbation on the Moon by the Sun is quite strong. But the giant planets also have a vast collection of small moons that orbit 1/3 of the way or more to the edge of their planet's Hill sphere. The Sun stronly perturbs them too. They are not bound to their planet's equator, but orbit in a wide range of inclinations.
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