[https://moon.nasa.gov/resources/429/the-moons-orbit/](https://moon.nasa.gov/resources/429/the-moons-orbit/)
OK so here is my question: this video looks like the moon is revolving around the earth but that it is not rotating on its axis at all. The earth is doing both in the video clearly and the moon “sees” other sides of the earth – b/c the earth is rotating. How exactly is the moon rotating WITHOUT turning? I assume it is turning b/c I’ve read that it does in fact rotate but I cannot wrap my brain about how it is working – how does something turn in front of you without you ever seeing the other side of it? And if it is b/c it is turning at the exact rate as the earth, why does the moon see the other side of the earth? Why aren’t they both locked? This question has bothered me for years and I’ve watched a bunch of videos on it and I just don’t get it and I feel stupid and I promise I’m not. LOL. Please – help me understand this.
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The animators were being a bit lazy and didn’t animate the rotation of the moon properly. It’s also quite slow. The moon completes one full rotation over 29.5 earth day. This means that a moon “day” is about an earth moon long.
You can literally see the Moon rotating in the animation. Look at the lunar maria (the dark grey splotches on the Earth-facing side of the Moon) and you can see that they are always facing the Earth. If the Moon didn’t rotate as it orbited the Earth, that would not be true. When the moon is at the top of screen, the lunar maria are facing towards the bottom of the screen, and when the moon is at the bottom of the screen, the maria are facing the top. That’s half a rotation. The moon completes one rotation in the same amount of time to complete an orbit.
I want to answer your question, but I’m having a hard time understanding where your confusion lies. What do you mean by “how exactly is the moon rotating WITHOUT turning”?
>but that it is not rotating on its axis at all
Yeah, that part isn’t true. It is rotating *at the same rate that it orbits* around Earth.
>I assume it is turning b/c I’ve read that it does in fact rotate
yea.
> but I cannot wrap my brain about how it is working – how does something turn in front of you without you ever seeing the other side of it
Uh…. just walk around someone but keep facing them. You know, “circle-strafe” in gaming.
> why does the moon see the other side of the earth? Why aren’t they both locked?
Because the moon is much smaller than the Earth. The Earth, given time, would become tidally locked *to the SUN*, not the moon. The moon and the other planets do play with that.
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