How does the moon work?


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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8 Answers

Anonymous 0 Comments

Earth and moon rotate and orbit in a way that you always see the same face of the moon from Earth. That’s it.

Anonymous 0 Comments

The Moon is going around the Earth in a circle all the time, completing one circle is about 28 days.

And the Earth’s rotation is a completely separate thing. It’s just a ball spinning one time per day. Nothing overly complicated.

Anonymous 0 Comments

There are two components to this:

1. The moon completes a rotation around Earth in the time of 1 month
2. The earth completes a rotation around itself in the time of 1 day

The moon phases are a result of the moon being in a different point around the Earth each day of the month. Also because the moon rotates exactly 30 times slower than Earth, it’s Earth-side face always points to Earth. That’s why we can only see one side of the moon, and the phenomena is called “tidal locking”.

Anonymous 0 Comments

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:


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:


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.

Anonymous 0 Comments

Not sure what you need but here. The earth rotates and do does the mood. say the earth rotates at x speed and the moon orbits at y speed (bolth measurements being vectors). from our earthly perspective the speed of the moons orbit will be x+y. something to keep in mind, speed is relative and a measurement can only be taken in relation to something else. another in case the first was off point. the earths rotatoin and the moons orbit arent related in the slightest

Anonymous 0 Comments

>Also, i am aphantastic, so please dont try to explain this by telling me to picture something spinning in my head

Well then, picture you standing up, holding your toddler by both hands, leaning backwards and spinning them around in the air. They love it.

Now also imagine that, instead of the both of you spinning around in the same spot, you are moving around in such a way you’re circling a tree.

That’s basically the sun/moon/earth system. You’re the Earth, the tree is the Sun, your kid is the Moon. Earth circles the Sun, Moon circles Earth. Moon always faces Earth (or at least, always presents the same face to the Earth since, unlike your toddler, the moon doesn’t have one definite face).

There’s only one catch: the Earth is actually spinning much faster than you spinning your toddler. The Moon doesn’t need to be held by the arms after all, it simply obeys the laws of gravity. The Earth has its own spin. Whilst the Moon circles the Earth in 28 days, the Earth rotates once every 24 hours. That’s what allows everyone around the globe to see the same phase of the moon on a given night/day cycle.

Any questions, do ask.

Anonymous 0 Comments

the moon’s rotation take about the same amount of time as its orbit.

so as the moon is orbiting Earth its rotating around itself at the same rate, hence the same side pepretually face us.

the moon being this close to us is acutally a bit of an oddity in the solar system and this causes both celestial bodies to actively slow its each other’s rotation, which is what eventually caused this: the Earth-Moon system is tidally locked.

Anonymous 0 Comments

The Moon orbits Earth in the same direction that Earth rotates, but because Earth rotates slightly faster the Moon appears to move backwards in its orbit to observers on Earth.