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What is retrograde planetary perihelion precession?

  1. Jun 19, 2011 #1
    I know what each word mean independently, I'm just confused as to what sort of motion is trying to be described as a whole.
  2. jcsd
  3. Jun 19, 2011 #2


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    hi magheera! :smile:

    perihelion precession means that the perihelion moves slightly each orbit

    usually, this is prograde, which means in the same direction as the orbit itself

    retrograde means the perihelion moves in the opposite direction to the orbit
  4. Jun 19, 2011 #3
    fantastic! Thanks so much.
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