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Pluto's wierd orbit

  1. Mar 30, 2003 #1
    [SOLVED] Pluto's wierd orbit

    Why does pluto orbit the sun the way it does? For that matter, why do all the planets orbit the way they do?
  2. jcsd
  3. Mar 30, 2003 #2


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    Since all the planets formed at roughly the same time from the same disc of dust (so the theory goes) all of them would necessarily be orbiting in the same direction. Pluto being so far out is most likely to be purturbed by interaction between it and the other outer planets, screwing up the orbit. It also may simply be that its an escaped moon of Neptune.
  4. Mar 30, 2003 #3
    Why isn't charon considred the planet, and pluto its moon? What's the current definition of a planet?
  5. Mar 30, 2003 #4


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    "Pluto" was discovered in 1930,

    When It was first discovered, it due to a search for a planet that was causing a variation in Neptune's orbit.

    It was also thought to be larger at that time. (At the resolution available at that time, the images of Pluto and Charon merged to together making what appeared to be one body.)

    When, in 1978, the two body nature of "Pluto" was discovered, it was just natural to designate the larger of the two bodies as Pluto, and the smaller as its moon.

    Pluto retains the designation of Planet mainly through tradition.
  6. Mar 30, 2003 #5


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    The biggere one is the planet.
  7. Apr 4, 2003 #6
    charon is bigger than pluto.
  8. Apr 4, 2003 #7
    Pluto has a radius of ~ 1,120 km, while Charon has a radius of ~ 593 km. Pluto is bigger than Charon.
  9. Apr 4, 2003 #8
    Pluto may be a body adopted by our solar system, orbiting in the sense of other solar bodies. What if Pluto had approached our system from the opposite direction - would it have been as likely to have been captured, or at all? What of comets, do they all orbit in the same sense as the planets?

    How about around a given planet; are there any substantial moons that circle in opposition to each other, or to parent planetary rotation in general? When we send an artificial satellite around a body, does it orbit with, or against the natural satellites present?

    In other words, what deviations are there for orbiting or rotating bodies in the Solar system from the preferred sense (Sun's?) of rotation? Neptune seems the odd god out.
  10. Apr 5, 2003 #9


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    Although there is some possibility that Pluto may be an escaped movement of Neptune, or an object completely foreign to our solar system, I think it far more likely than that it is simply a very large Kuiper Belt object. The Kuiper Belt is an asteroid Belt just outside the orbit of Neptune that appears to mark the end of the planetary system, and the beginning of the Oort cloud, just as the inner asteroid Belt appears to mark the end of the Rocky planets and the beginning of the gas giants.

    One of the largest moons in the solar system, Triton, orbits Neptune in the opposite direction from all other satellite and planetary orbits. This gives rise to the conjecture that it, too may be a very large Kuiper Belt object. Only in this case, one that actually has gotten trapped into and orbit. Further evidence is the fact that this orbit is far more elliptical than any of the other satellites in the solar system, and that it is decaying. Eventually, Triton will pass too close to Neptune and get torn apart, adding to Neptune's already complex ring system. Almost makes one wonder if that is where all the material for Neptune's rings originally came from.

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