How does the moon work?

Question

I understand the moon phases, so I don’t need information on that. I can’t wrap my head around the way the earth rotates and the moon orbits at the same time. I have read anton of articles, but just get more and more confused. Do they go in the same direction? How does this work??

Also, i am aphantastic, so please dont try to explain this by telling me to picture something spinning in my head. That just gives me a headache.

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Answer 1

The moon is what is called tidally locked to the Earth (its not uncommon for moons to do this).
What that means is that the moons rotation (the rate it spins on its own axis) is synchronized with its orbit (the rate it circles the earth). Both are about 29.5 days (aka about 1 month, the origin of the term month coming from moon).

Since you mention not being able to visualize things, you might want to draw this out are use objects instead. You can get an idea of how this works by taking three objects, one representing the sun, one the earth, one the moon and placing them in a line.
It would look like this:

SUN —— EARTH —– MOON.

Every 29.5 days the three objects will line up the same way. However the sun and the earth may be rotated differently, the same side of the moon will be facing towards the earth.

If you now advance only half that time 14.75 days it would look like this:

SUN —– NOOM —– EARTH

This is not a typo, I deliberately put the “MOON” backwards to reinforce that the moon will have the same side facing towards the Earth, even though a different side of the Earth may be facing towards the moon.

Another way to model this is to find an object in your house, that you can walk around in a circle. Now stand with your left side facing the object and point at it with your left hand. Walk in a circle around the object but ALWAYS keep your left side facing it and pointing at the object. You will see different sides of the object, but the object will only be able to see one side of you.

The reasons why this happens are related to physics and loss of energy in the system and all that, you can read more about that part if you want, but basically we’re in a stable point where, unless some outside force intervenes, the moon will stay locked to the earth like this.