I'm a student who's trying to analyze some data for the distance between the earth and the moon (specifically, to model with sinusoidal functions in our math class.) In my research, I gathered some data, and I saw the expected changes in Earth-Moon distance (due to the elliptical orbit). However, I also saw that the distance at apogee and perigee changes as well:
Why is this? I saw another question which asked why the time between apogee and perigee varied, and it was due to the effects of the sun. Edit: Looks like I misunderstood this, sorry. Could this phenomenon be because of the same reason as in the linked question?