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Why does a comet get pushed away by the sun when it gets too close?

  1. Jun 29, 2010 #1
    This was shown in a text book about the two body problem, and they compared it to the energy potential of two atoms, but the sun and comet don't experience charge so that 'when it gets too close the nuclei repel each other'.
    It mentioned something about centrifugal force, but I don't understand where that comes into play.
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  3. Jun 29, 2010 #2


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    Dearly Missed

    The comet isn't pushed away at all.

    Rather, the sun isn't able to pull it strongly enough to prevent the comet from leaving the system.
  4. Jun 29, 2010 #3


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  5. Jun 29, 2010 #4


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    There is a very slight "solar wind" consisting of particles expelled by the sun. That is what causes the lighter particles of a comet's tail to lag behind it. But the effect is far too small to even slow down the comet itself noticably and even the tail only "lags"- it still follows the comet around the sun.
  6. Jul 3, 2010 #5
    I haven't checked on this but I was under the impression that the tail of a comet is not so much 'left behind' as actively 'blown away' by the solar wind?

    The result being that it mostly points away from the sun rather than along the path of the comet.
  7. Jul 3, 2010 #6


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    You should be clear to distinguish between the ion tail and the dust tail. The ion tail points directly away from the sun while the dust trail rather roughly traces the orbital motion.
  8. Jul 3, 2010 #7
    I doubt the text stated that the way in which a Meteor moves away from the Sun is similar to the way nuclei repel each other. The two nuclei repel each other due to charge but the reason why the comet moves away from the sun is because as it moves towards the sun it converts potienial energy into kinetic energy causing it to move faster giving it the velocity and centrifugal force (<there you go) to avoid falling into the sun.

    Hope this helps :)
  9. Jul 3, 2010 #8
    Sounds like a thoroughly bad book to me, throw it away.
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