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Anomalistic, Sidereal, Nodal month, etc

  1. Sep 17, 2008 #1
    Anomalistic, Sidereal, Nodal month, etc....

    Earth's moon's anomalistic, sidereal, and nodal months all take about the same length of time to complete within a few minutes/seconds of each other. Why is that? Can one be independent of the other?

    Let's say that instead of the moon's typical draconic month of 27.212220 days, it was 30.some odd days, and yet somehow the sidereal, synoidc, and anomalistic months remained as they are right now, with respect to the 5.1 degrees to the ecilptic. Can a draconic and/or anomalistic month deviate? Can any of the moon's lunar months deviate like that, or is that totally illogical? Must they stay closely related by minutes and seconds as they already are?

    Are there any known moons in our system who's nodal, anomalistic months are similar to what I described? I would be a very happy person if I could grasp that. If it's illogical, what is the math to figure synodic, sidereal, anomalistic, draconic months in relation to each other?

    Also, what determines an anomalistic month, when it returns to the same apogee/peregee after just 9 years? Why does it rotate like that? Similarly, the ascending and descending nodes do the same thing for the nodal months. Why aren't the nodal months and anomalistic months exactly the same?

    Last edited: Sep 18, 2008
  2. jcsd
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