# The Naked Scientists Forum

### Author Topic: Where does the moon get its kinetic energy from to remain orbiting the earth?  (Read 2019 times)

#### Thebox

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##### Where does the moon get its kinetic energy from to remain orbiting the earth?
« on: 06/12/2015 03:13:28 »
The thought has just occurred, Newton said that a body in motion will remain in motion unless acted upon by external forces, and we presume a body orbiting another body is for this reason, however , if the moon acts on the oceans and the oceans act on the moon, why does the moon continue to orbit because there is acting external forces?

Where does the Ke come from?

If the moon drags the ocean, then the ocean drags the moon back.

#### ijaz

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #1 on: 06/12/2015 04:38:19 »
The gravitational force between the earth and the moon.

#### chiralSPO

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #2 on: 06/12/2015 04:42:45 »
The thought has just occurred, Newton said that a body in motion will remain in motion unless acted upon by external forces, and we presume a body orbiting another body is for this reason, however , if the moon acts on the oceans and the oceans act on the moon, why does the moon continue to orbit because there is acting external forces?

Where does the Ke come from?

If the moon drags the ocean, then the ocean drags the moon back.

That's a great question!

The oceans/tides are actually speeding the moon up! It's more of a drag on the Earth's rotation (and is making our day longer and longer) And it also results in the moon moving away from us (the moon is moving faster, but it has a much longer path to follow around the Earth, so the lunar month will also increase in duration).

#### chintan

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #3 on: 06/12/2015 13:09:53 »
They have generators up there

#### Space Flow

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #4 on: 07/12/2015 06:23:25 »
The thought has just occurred, Newton said that a body in motion will remain in motion unless acted upon by external forces, and we presume a body orbiting another body is for this reason, however , if the moon acts on the oceans and the oceans act on the moon, why does the moon continue to orbit because there is acting external forces?

Where does the Ke come from?

If the moon drags the ocean, then the ocean drags the moon back.

That's a great question!

The oceans/tides are actually speeding the moon up! It's more of a drag on the Earth's rotation (and is making our day longer and longer) And it also results in the moon moving away from us (the moon is moving faster, but it has a much longer path to follow around the Earth, so the lunar month will also increase in duration).

Just to add a few more pixels to the picture beautifully painted by "chiralSPO", Because of an effect on Spacetime called "Frame Dragging" The attraction felt by the Earth and the Moon is not in a direct line between their two centres, but dragged around Earth Spinward from the moon's perspective.
That is why it results in a backward force on the Earth's spin.
From the Moon's point of view this results in it feeling some Forward pressure along it's line of orbit, as well as the downward pressure represented by the Earths Mass.
That's why the Moon gains a little bit of orbital speed as the Earth turns.

As the moon drags the ocean, the ocean drags the moon forward.

Hope that helps.
« Last Edit: 07/12/2015 06:25:49 by Space Flow »

The following users thanked this post: chiralSPO, Thebox

#### Thebox

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #5 on: 07/12/2015 10:59:24 »
The thought has just occurred, Newton said that a body in motion will remain in motion unless acted upon by external forces, and we presume a body orbiting another body is for this reason, however , if the moon acts on the oceans and the oceans act on the moon, why does the moon continue to orbit because there is acting external forces?

Where does the Ke come from?

If the moon drags the ocean, then the ocean drags the moon back.

That's a great question!

The oceans/tides are actually speeding the moon up! It's more of a drag on the Earth's rotation (and is making our day longer and longer) And it also results in the moon moving away from us (the moon is moving faster, but it has a much longer path to follow around the Earth, so the lunar month will also increase in duration).

I am not quite sure how that answers the question?

Ok, which way does the moon travel relative to the Sun?  meaning does the moon ''chase'' the Sun or does the Sun ''chase'' the moon?

And does the moon always remain opposite of the sun relative to the earth in the middle?

#### Space Flow

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #6 on: 07/12/2015 11:10:47 »
Oh my!!! chiralSPO, looks like you have to start from why the Earth is no longer considered flat.
Good luck.

#### chiralSPO

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #7 on: 07/12/2015 15:10:35 »

I am not quite sure how that answers the question?

Ok, which way does the moon travel relative to the Sun?  meaning does the moon ''chase'' the Sun or does the Sun ''chase'' the moon?

And does the moon always remain opposite of the sun relative to the earth in the middle?

The moon orbits the Earth. The Earth orbits the sun (with a period that is approximately 1 year). The Earth also rotates on its own axis (with a period that is approximately 1 day). The 1-day rotation of the Earth is responsible for the apparent daily motion of the sun, moon and stars. The fact that the moon is orbiting the Earth in the same direction that the Earth is spinning (spinward) means that it apparently moves a little more slowly across the sky, which is why the relative position of the sun and moon changes from day to day (and repeats in a monthly cycle).

#### Thebox

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #8 on: 07/12/2015 23:16:53 »

The moon orbits the Earth. The Earth orbits the sun (with a period that is approximately 1 year). The Earth also rotates on its own axis (with a period that is approximately 1 day). The 1-day rotation of the Earth is responsible for the apparent daily motion of the sun, moon and stars. The fact that the moon is orbiting the Earth in the same direction that the Earth is spinning (spinward) means that it apparently moves a little more slowly across the sky, which is why the relative position of the sun and moon changes from day to day (and repeats in a monthly cycle).

The moon orbits the earth the same direction has the earth's spin, really?   from my location the moon travels left to right across the sky, but we spin right to left. That would be the opposite way would it not?

#### Space Flow

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #9 on: 08/12/2015 00:34:09 »
The moon orbits the earth the same direction has the earth's spin, really?   from my location the moon travels left to right across the sky, but we spin right to left. That would be the opposite way would it not?

Let's take it back to basics. The Moon orbits the Earth in the same direction as the Earth is spinning.
The Moon takes 27 days, 7 hours, 43 minutes, 11.6 seconds to complete one orbit of the Earth.
While the Moon is taking all that time to go around once, the Earth spins on it's axis in the same direction every 23 Hours and 56 minutes.
If you are standing on the Moon you would see the earth spin in the same direction you are orbiting 27.4 times for every one time you completed one orbit.
Similarly if you are standing on the Earth even though you are spinning in the same direction as the Moon is orbiting, the Earth's spin would overtake the moon 27.4 times in every one full Moon orbit.
You would see the Moon apparently moving in the opposite direction in your sky to the actual direction it is moving.
Hope that helps.
« Last Edit: 08/12/2015 00:35:56 by Space Flow »

#### Thebox

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #10 on: 08/12/2015 01:09:31 »
The moon orbits the earth the same direction has the earth's spin, really?   from my location the moon travels left to right across the sky, but we spin right to left. That would be the opposite way would it not?

Let's take it back to basics. The Moon orbits the Earth in the same direction as the Earth is spinning.
The Moon takes 27 days, 7 hours, 43 minutes, 11.6 seconds to complete one orbit of the Earth.
While the Moon is taking all that time to go around once, the Earth spins on it's axis in the same direction every 23 Hours and 56 minutes.
If you are standing on the Moon you would see the earth spin in the same direction you are orbiting 27.4 times for every one time you completed one orbit.
Similarly if you are standing on the Earth even though you are spinning in the same direction as the Moon is orbiting, the Earth's spin would overtake the moon 27.4 times in every one full Moon orbit.
You would see the Moon apparently moving in the opposite direction in your sky to the actual direction it is moving.
Hope that helps.

Arggh . yes thank you, I understood the over taking part.

#### Thebox

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #11 on: 08/12/2015 01:12:03 »
So if there is drag. there is torque?

earth spirals space time?
« Last Edit: 08/12/2015 01:15:37 by Thebox »

#### Space Flow

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #12 on: 08/12/2015 01:35:03 »
So if there is drag. there is torque?
Yes. It results in a transfer of angular momentum from the Earth's spin to the Moon's orbital velocity.

earth spirals space time?
Yes, It was predicted by General Relativity, and experimentally confirmed by Gravity Probe B.
It is explained in understandable terms in my post: http://www.thenakedscientists.com/forum/index.php?topic=65064.0

Hope that helps

#### Thebox

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #13 on: 08/12/2015 01:40:37 »
So if there is drag. there is torque?
Yes. It results in a transfer of angular momentum from the Earth's spin to the Moon's orbital velocity.

earth spirals space time?
Yes, It was predicted by General Relativity, and experimentally confirmed by Gravity Probe B.
It is explained in understandable terms in my post: http://www.thenakedscientists.com/forum/index.php?topic=65064.0

Hope that helps

space time only exists between two bodies?

#### Space Flow

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##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #14 on: 08/12/2015 02:09:59 »
That is a very good question!

space time only exists between two bodies?
I do hope you didn't get that idea from anything I said.
Spacetime or Timespace whichever way you want to think about it is what the Universe consists of. (Check out De Sitter Spacetime).
Matter as we know it is a low percentage impurity. Matter exists and occupies Spacetime. It causes warpages in the flatness of spacetime. Matter/Energy is conserved. Spacetime is not.
Therefore spacetime expands while Matter/Energy stay the same.
Every moment that goes past by any timing method you want to use, there is more spacetime.

Ok with all of the above having been said, I see that I am not really answering your question. Damn...
This really is a great question!
I'll rephrase it and see if we can arrive at an answer:
Is there anywhere in the Universe that can not be defined by the space between two units of Mass/Energy?
I would "guess" and say you are right and "spacetime only exists between two bodies". But I can not think of a way of justifying such a statement.
Maybe someone else can have a go at this.

Sorry I failed you.

#### The Naked Scientists Forum

##### Re: Where does the moon get its kinetic energy from to remain orbiting the earth?
« Reply #14 on: 08/12/2015 02:09:59 »