I'm trying to understand what exactly causes lunar nodal precession.

Based on this article, my understanding is that precession of the plane of the moon's orbit is what causes the motion of the Moon's nodes along the ecliptic. Is this a correct understanding? Thinking more deeply about it, it seems that Apsidal precession could also impact the location of the nodes, but I would imagine this motion would have a smaller effect.

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  • $\begingroup$ From my answer, "The torque caused by the Earth trying to pull the Moon into an equatorial orbit causes the nodal precession". Robjohn has some nice anims of nodal precession here. $\endgroup$
    – PM 2Ring
    Commented Mar 27 at 20:56
  • $\begingroup$ We normally consider the Moon's nodal and apsidal precessions separately. They have different periods, and opposite rotation directions. $\endgroup$
    – PM 2Ring
    Commented Mar 27 at 21:01
  • $\begingroup$ Thanks for the helpful responses @PM2Ring! After reviewing these links, what I'm not quite following yet is why the torque caused by the Earth trying to pull the Moon into an equatorial orbit would lead to periodic motion - is there something I’m missing? My understanding after reviewing Robjohn’s animations is that the earth’s torque causes the plane of the lunar orbit to basically wobble, leading to nodal precession - is that a fair characterization? Thanks again! $\endgroup$
    – Stephen W.
    Commented Mar 28 at 14:13
  • $\begingroup$ Yes, that's fair. The Earth-Moon system orbiting around the EMB (Earth-Moon barycentre) precesses like a gyroscope. I have more info & diagrams here: astronomy.stackexchange.com/a/47503/16685 $\endgroup$
    – PM 2Ring
    Commented Mar 28 at 14:45


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