Unraveling the Mystery of the Moon's Non-Spinning Rotation

[Hurkyl]

The Moon has a ... Earthrise, Earthset.

Misspoke?

 

[turbo]

Misspoke?

Funny, but true. Gravitationally-locked satellites have some interesting qualities.

 

[ttown_okie]

Excuse my delayed response, I am at work.

I think you all have your terminology wrong. The moon does not rotate about its axis at all, it rotates about the Earths axis. A body is said to be in rotation about its axis if the center of the axis resides inside the body. In the moons case, the axis of rotation resides inside the Earth. This is known as an orbital.

The moon is not rotating abouts its own axis. If the Earth were to instantly disappear the moon would fly off on a tangent form the Earth with no spin about its axis.

 

[ttown_okie]

The moon orbits the earth, if it didn't spin we'd see a different piece of the moon each night. Your picture supports the fact it is spinning by only showing one piece of the moon ever being shown.

If the moon had any spin at all we would be able to see all sides of it, because we can not, you know that the moon is not spinning on its axis.

 

[ttown_okie]

The Moon does indeed rotate about its own axis. The Moon has a sunrise, sunset, starrise starset and Earthrise, Earthset.

The fact that we here on Earth see one side facing us at all times does not mean it does not rotate, in fact, it proves it does rotate.

Having sunlight visible on all parts of a body based upon position in time does not equate to rotation about its axis. The sun is an outside observer of the moon orbiting in a circular path. Of course it will see sun on all its sides during its orbit because one side of the moon always faces Earth.

 

[ttown_okie]

You can see it right here that there is no rotation about its axis.

http://upload.wikimedia.org/wikipedia/commons/b/ba/Lunar_libration_with_phase_Oct_2007_450px.gif

 

[turbo]

TT, the Moon rotates about its own axis. It does so in synch with its orbit around the Earth, because the Moon is gravitationally locked to the Earth, so we see the same face all the time. A rotational period of ~month may seem long to you, but it is real.

 

[JaredJames]

If the moon had any spin at all we would be able to see all sides of it, because we can not, you know that the moon is not spinning on its axis.

Not true, it is spinning but timed perfectly so we only see one side.

If it wasn't spinning, the same side of the moon would always face the sun and we would see a different area each night.

Your picture supports us not you.

 

[Timoothy]

The moon is not rotating about its own axis at any point in its orbital path.

Below is a gif that might help.
Notice that the red dot makes one complete rotation around the axis (green dot) of the moon during a complete orbit of earth.

http://h1.ripway.com/cluelusshusbund/Moon/MoonEarthOneRotation.gif

 

[ttown_okie]

Not true, it is spinning but timed perfectly so we only see one side.

If it wasn't spinning, the same side of the moon would always face the sun and we would see a different area each night.

Your picture supports us not you.

I do not think so, the orbit around the Earth is the reason one side faces the Earth. If the moon was spinning this would not happen. If I fly a plane in an orbit around the Earth, at no point in time did I have to apply a rotational force to my plane to correct for the curvature of the Earth, I simply flew parallel to the Earth with my engine always applying thrust perpendicular to the Earth. It is the same with the moon, the core of the moon is not imparting any spin at all to the moon itself. One side faces the Earth because of gravity. therefore the moon does not rotate abouts its own axis. I think you mean that it rotates about the Earths axis.

 

[JaredJames]

I do not think so, the orbit around the Earth is the reason one side faces the Earth. If the moon was spinning this would not happen. If I fly a plane in an orbit around the Earth, at no point in time did I have to apply a rotational force to my plane to correct for the curvature of the Earth, I simply flew parallel to the Earth with my engine always applying thrust perpendicular to the Earth. It is the same with the moon, the core of the moon is not imparting any spin at all to the moon itself. One side faces the Earth because of gravity. therefore the moon does not rotate abouts its own axis. I think you mean that it rotates about the Earths axis.

What does the core have to do with anything? The core isn't the reason the Earth spins so why is the moon special?

 

[ttown_okie]

Below is a gif that might help.
Notice that the red dot makes one complete rotation around the axis (green dot) of the moon during a complete orbit of earth.

http://h1.ripway.com/cluelusshusbund/Moon/MoonEarthOneRotation.gif

I understand that diagram, what that shows is that the moon is rotating about the Earths axis and the moon is not rotating about its own axis. If it was, one side could not always face Earth.

If I take a stone and tie it to the end of a string and swing it around my body, it orbits me just like that picture. The stone is not rotating or spinning about itself.

 

[ttown_okie]

What does the core have to do with anything? The core isn't the reason the Earth spins so why is the moon special?

The cores of the Earth and the moon are vastly different. The core of the Earth supports a strong electromagnetic field around the Earth, the moon does not have this. I did not say the core is the absolute reason the Earth spins, but it is an important piece of the puzzle as to why. What is your theory about why the Earth spins, I can describe mine if you like.

 

[JaredJames]

The cores of the Earth and the moon are vastly different. The core of the Earth supports a strong electromagnetic field around the Earth, the moon does not have this. I did not say the core is the absolute reason the Earth spins, but it is an important piece of the puzzle as to why. What is your theory about why the Earth spins, I can describe mine if you like.

I don't care for your theory, neither does science. The Earth's core has nothing to do with the reason the Earth is spinning.

 

[Borek]

ttown, think about it this way. Earth rotates - no doubt about it. Now imagine a geosynchronous satellite. It always hangs exactly over the same point on the Earth surface, so it always sees exactly the same view of the Earth - as if the Earth wasn't rotating. So, if you were living at geosynchronous satellite you would think Earth doesn't rotate, even if it does.

This is not much different from what happens to the Moon - it rotates, but from the point of view of someone living on the Earth it always shows the same side, so it looks like if didn't.

 

[ttown_okie]

Do you all think the the ISS has to apply rotational boosters continuously to keep one side always facing the Earth? Is the ISS rotating about its own axis too?

 

[ttown_okie]

ttown, think about it this way. Earth rotates - no doubt about it. Now imagine a geosynchronous satellite. It always hangs exactly over the same point on the Earth surface, so it always sees exactly the same view of the Earth - as if the Earth wasn't rotating. So, if you were living at geosynchronous satellite you would think Earth doesn't rotate, even if it does.

This is not much different from what happens to the Moon - it rotates, but from the point of view of someone living on the Earth it always shows the same side, so it looks like if didn't.

I can visualize what you are saying but the satellite is orbiting the Earth, not he other way around.

 

[ttown_okie]

I don't care for your theory, neither does science. The Earth's core has nothing to do with the reason the Earth is spinning.

Please enlighten us.

 

[JaredJames]

Please enlighten us.

http://en.wikipedia.org/wiki/Earth's_rotation

No one knows for sure, but the current theories have nothing to do with the core causing the spin.

It's not "us", it's just you.

 

[nobahar]

I found this animation to be useful:
http://www.youtube.com/watch?v=exIpL0Uhr_k&feature=related

 

[ttown_okie]

http://en.wikipedia.org/wiki/Earth's_rotation

No one knows for sure, but the current theories have nothing to do with the core causing the spin.

It's not "us", it's just you.

I agree that no one knows for certain but it is quite arrogant to claim the core has nothing to do with rotation of the Earth when nobody knows. I think the magnetic field flowing through the core has something to do with the Earth rotation and if the core was comprised with an entirely different composition it would quite likely affect the rotation of the Earth.

 

[JaredJames]

I agree that no one knows for certain but it is quite arrogant to claim the core has nothing to do with rotation of the Earth when nobody knows. I think the magnetic field flowing through the core has something to do with the Earth rotation and if the core was comprised with an entirely different composition it would quite likely affect the rotation of the Earth.

There's a difference between the spin of the Earth affecting the core and the core spinning being the cause of the Earth spinning. You claimed the latter.

It is currently believed the core is what generates the magnetic field (http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magearth.html)

 

[ttown_okie]

There's a difference between the spin of the Earth affecting the core and the core spinning being the cause of the Earth spinning. You claimed the latter.

At no point have I ever said that the core spinning cause the Earth to spin. In fact have have not said why I think the Earth spins in this thread at all. I did acknowledge that yes I do think the core has something to do with it. I do not think a spinning core explains it.

 

[JaredJames]

At no point have I ever said that the core spinning cause the Earth to spin. In fact have have not said why I think the Earth spins in this thread at all. I did acknowledge that yes I do think the core has something to do with it. I do not think a spinning core explains it.

I did not say the core is the absolute reason the Earth spins, but it is an important piece of the puzzle as to why.

In other words, it's involved, it's part of the cause. This is wrong.

 

[Borek]

I can visualize what you are saying but the satellite is orbiting the Earth, not he other way around.

This is relative and depends only on where you put your reference point.

But if you are not convinced, put a chair in the middle of the room and ask someone to sit there and tell you what they see. Go around in circles. Go around trying to face the same wall all the time. For sure you were not rotating, but ask the person on the chair if they have seen always the same side of your body, as it happens when we look at the Moon. Now, go around the chair always facing the sitting person. They see your face all the time now, but while making the circle you have been facing all sides of the room - so you have rotated around your axis.

 

[ttown_okie]

The moon has no rotation about its axis, it rotates about the Earth axis.

If I tie a rock to a string and swing it around my body, you will notice the rock is not rotating around its axis. The rock is not spinning at all. try and see for yourself. it will lok similar to this:

http://upload.wikimedia.org/wikipedia/commons/b/ba/Lunar_libration_with_phase_Oct_2007_450px.gif"

 

[JaredJames]

Someone please put an end to this nonsense.

This is the third repetition of something disagreeing with him.