Does the Moon Rotate?

Beyond the boundaries of established science an avalanche of exotic ideas compete for our attention. Experts tell us that these ideas should not be permitted to take up the time of working scientists, and for the most part they are surely correct. But what about the gems in the rubble pile? By what ground-rules might we bring extraordinary new possibilities to light?

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Re: Does the Moon Rotate?

Unread postby chrimony » Fri Nov 01, 2013 6:34 am

jtb wrote:Chrimony, my conclusion was that your small bowl, which you say is the moon, did not rotate; therefore, there was no discrepancy between your experiment and mine. Neither your moon nor mine rotated.


Let's be very clear here. In your experiment, you stuck your arm out with your palm facing you and spun around, and your palm always faced you. If you perform the same experiment holding the two bowls, the smaller bowl will not always face you. Do you agree or not?

Liberation is oscillation, not rotation, due to orbits not being perfect circles.


You haven't given a mechanism to explain the oscillation. Are you claiming that the moon is physically oscillating back and forth? Why does not orbiting in a perfect circle cause the moon to oscillate?

By the way, it's spelled libration. I misspelled it in one of my posts.
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Re: Does the Moon Rotate?

Unread postby Michael V » Fri Nov 01, 2013 6:58 am

jtb,

moon round earth 3.jpg

Is this something like what you had in mind. The dotted lines show a line between the centre of the orbiting Moon and the system barycentre (indicated by the blue dot). The red and green lines indicate that the view from the Earth would slightly favour one side of the Moon during its orbit. Seemingly, this only becomes apparent from an elliptical rather than circular orbit. However, presumably the Earth also orbits around the blue dot barycentre and may also contribute...or not?.

One presumes the calcs have been done with regard to the "axially" rotating model, I wonder if this model might produce exactly the same results. I have a sneaking suspicion it may well be the case. If that were so, both models would continue to be equally valid. So how and why, would one choose between the two?.


Michael
Last edited by Michael V on Fri Nov 01, 2013 7:23 am, edited 1 time in total.
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Re: Does the Moon Rotate?

Unread postby Michael V » Fri Nov 01, 2013 7:04 am

chrimony,

chrimony wrote:Reasoned arguments that have already been given. And you already gave a position early in this thread: "The Moon does not rotate around its own axis and it does not revolve around its own axis. The Moon does rotate around the Earth with one side permanently facing the Earth and it does revolve around the Earth with one side permanently facing the Earth."

The intent of my choice of words on that occasion was to caste doubt upon the certainty of the accepted model, without necessarily denying its validity. If I did not achieve that, then it was a failure on my part. Let me state now, that at this stage I am attempting to remain neutral.


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Re: Does the Moon Rotate?

Unread postby jtb » Fri Nov 01, 2013 7:51 pm

I made some diagrams that explain my position concerning rotation but can't upload them or copy and paste to display. I have them in Powerpoint, Word, pdf, hmtl, and jpeg formats, but can't copy and paste onto this site. The diagrams would probably help you understand my position. My e-mail is jtban@hotmail.com if you would like a copy or could reconstruct them so the site will allow me to post. Thanks.
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Re: Does the Moon Rotate?

Unread postby jtb » Fri Nov 01, 2013 8:05 pm

chrimony wrote:Let's be very clear here. In your experiment, you stuck your arm out with your palm facing you and spun around, and your palm always faced you. If you perform the same experiment holding the two bowls, the smaller bowl will not always face you. Do you agree or not?


No.

chrimony wrote:You haven't given a mechanism to explain the oscillation. Are you claiming that the moon is physically oscillating back and forth? Why does not orbiting in a perfect circle cause the moon to oscillate?

By the way, it's spelled libration. I misspelled it in one of my posts.


Chrimony, I can explain rotation but not libration. What is your explanation of the mechanism that causes longitude, latitude, and diurnal libration?
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Re: Does the Moon Rotate?

Unread postby chrimony » Sat Nov 02, 2013 2:27 am

jtb wrote:I made some diagrams that explain my position concerning rotation but can't upload them or copy and paste to display. I have them in Powerpoint, Word, pdf, hmtl, and jpeg formats, but can't copy and paste onto this site. The diagrams would probably help you understand my position.


If you have jpegs, just put them on Photobucket or some other free hosting site and link to them.

jtb wrote:
chrimony wrote:Let's be very clear here. In your experiment, you stuck your arm out with your palm facing you and spun around, and your palm always faced you. If you perform the same experiment holding the two bowls, the smaller bowl will not always face you. Do you agree or not?


No.


Really? Because I just performed it. I put a little mark on the edge of the smaller bowl, it was floating freely in the larger bowl and able to spin easily. Starting with everything still, I then held it out with my arm and rotated myself. The mark kept the same direction with respect to the non-rotating room. From my point of view, it looked like the marked bowl was rotating.

It's a crude experiment, and it's easy to mess it up by having the smaller bowl touch the sides of the larger bowl or have motion before you start, and the water isn't perfectly frictionless, but the basic principle is illustrated: It did not always show me the same face, quite unlike an attached palm. The same is true for objects in space. They rotate freely, also quite unlike your attached palm. For them to show the same face to a body they orbit, they have to rotate.

Chrimony, I can explain rotation but not libration. What is your explanation of the mechanism that causes longitude, latitude, and diurnal libration?


If you can't explain libration, though earlier you claimed it was "oscillation, not rotation, due to orbits not being perfect circles", then your model fails in comparison to the standard one. I've given my explanation for libration in longitude already:

chrimony wrote:"Because the orbit of the moon is elliptical, its orbital velocity speeds up and down, which results in a difference between the moon's orbital velocity and rotation. This is detected as libration in longitude, which means we can see more of the left and right sides, as if it was wobbling slightly back and forth in its orbit."


As for latitude and diurnal, I'm satisfied with the explanations given in the Wikipedia page.
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Re: Does the Moon Rotate?

Unread postby Michael V » Sat Nov 02, 2013 3:06 am

jtb,

jtb wrote:Chrimony, I can explain rotation but not libration. What is your explanation of the mechanism that causes longitude, latitude, and diurnal libration?

Diunrnal libration is a terrestrial view point caused by the Earth's rotation.
Latitude libration is due to the Moon's orbital plane relative to Earth.
Both of these are model agnostic and are of no consequence to the argument in hand.

Longitude libration is either caused by the eccentricity of the Moon's orbit, i.e. an elliptical orbit:

being at a slightly different rate to its rate of rotation
OR
having a slightly different viewing angle from Earth (see the diagram in my previous post)

The argument that I put forward in my previous post was that both of these options produce the same result and so libration is no use as a method to distinguish between the two models and therefore answer the question at hand.

Other questions that need to be addressed by one model or another, or both:
- why does a body "rotate"
- what has caused the Moon to rotate at exactly the same rate as one elliptical orbit
- if the Moon doesn't rotate, why not?
- does tidal locking explain the situation?.....or not?


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Re: Does the Moon Rotate?

Unread postby Michael V » Sat Nov 02, 2013 3:29 am

chrimony,

chrimony wrote:The same is true for objects in space.

Whoa there. Unjustified leap of reasoning dude.

chrimony wrote:They rotate freely...

Well if objects in space rotate "freely", how come the Moon only rotates once per orbit?. Something seems to have affected its ability to rotate "freely"; if indeed it rotates.

chrimony wrote:For them to show the same face to a body they orbit, they have to rotate.

You're at it again

chrimony wrote:Really? Because I just performed it. I put a little mark on the edge of the smaller bowl, it was floating freely in the larger bowl and able to spin easily. Starting with everything still, I then held it out with my arm and rotated myself. The mark kept the same direction with respect to the non-rotating room. From my point of view, it looked like the marked bowl was rotating.

Are you suggesting the bowls are in gravitational orbits?. If not, how does this experiment apply to the question of rotation in gravitational orbit?.

On the one hand, there is the claim that bodies in space rotate freely, but on the other hand, the simple fact of orbit absolutely demands that the bodies are not "free".


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Re: Does the Moon Rotate?

Unread postby chrimony » Sat Nov 02, 2013 4:09 am

Michael V wrote:The argument that I put forward in my previous post was that both of these options produce the same result and so libration is no use as a method to distinguish between the two models and therefore answer the question at hand.


You made a guess that the result was the same. You didn't actually do any calculations.

Michael V wrote:
chrimony wrote:The same is true for objects in space.

Whoa there. Unjustified leap of reasoning dude.


Unjustified? You mean the satellites in space that spin (rotate) while orbiting at arbitrary rates don't exist? That the Earth and Moon don't orbit the Sun while showing rotation with respect to the Sun? And yet we are given palms attached to hands and balls attached to strings as counter-arguments, or models without calculations and presumed to give the same result. Who is making the unjustified assumptions?


Well if objects in space rotate "freely", how come the Moon only rotates once per orbit?. Something seems to have affected its ability to rotate "freely"; if indeed it rotates.


You very well know that the standard answer is tidal locking, which happens gradually over a long time.

Are you suggesting the bowls are in gravitational orbits?. If not, how does this experiment apply to the question of rotation in gravitational orbit?.


I'm suggesting as far as analogous experiments go, the bowls match much more closely to what we see in space than jtb's palm experiment or your ball on a string. At some point, if you can't acknowledge points like this conversation is useless. I am at that point.

On the one hand, there is the claim that bodies in space rotate freely, but on the other hand, the simple fact of orbit absolutely demands that the bodies are not "free".


And on another hand, neither you nor jtb have given a mechanism that explains why satellites can rotate at arbitrary spin rates while orbiting, or why the Earth and Moon orbit the Sun while rotating.
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Re: Does the Moon Rotate?

Unread postby Michael V » Sat Nov 02, 2013 5:02 am

chrimony,

chrimony wrote:or models without calculations and presumed to give the same result. Who is making the unjustified assumptions?

Yeah, that was me.

and...
chrimony wrote:It did not always show me the same face, quite unlike an attached palm. The same is true for objects in space. They rotate freely, also quite unlike your attached palm. For them to show the same face to a body they orbit, they have to rotate.
...that was you!.

Unjustified assumptions, are just so easy, don't you agree?.


Whether jtb's alternative explanation of the Moon's rotation/non-rotation is correct or not, I really don't see that the standard explanation is as complete and ironclad as you imply.

chrimony wrote:I'm suggesting as far as analogous experiments go, the bowls match much more closely to what we see in space than jtb's palm experiment or your ball on a string.

It could be argued that a horse looks more like a elephant than a giraffe does, but it does not follow that studying horses will not necessarily give me more insight about elephants than studying giraffes would. In truth, both are useless as "analogies". You will again notice that I suggested the "piece of string" scenario as a visualisation, not an analogy.


chrimony wrote:And on another hand, neither you nor jtb have given a mechanism that explains why satellites can rotate at arbitrary spin rates while orbiting, or why the Earth and Moon orbit the Sun while rotating.

Have you?. Can you explain please, I am interested.

chrimony wrote:You very well know that the standard answer is tidal locking, which happens gradually over a long time.

Quite so, I am aware of the "tidal locking" explanation. However, I have read a bit about it, but did not fully understand how it works to produce the single rotation per elliptical orbit claimed for moons. For example, does the moon start with no rotation and acquire rotation, or start with more rotation and loose rotation. Perhaps you would be kind enough to explain.
Also, what happens to satellites you mentioned. Why are the spin rates arbitrary?. Do they attain a certain spin rate that stays fixed?, or does it change over time?. Do all satellites spin in orbit if not corrected?. What about satellites in perfectly circular equatorial orbits?. What about an idealised case of a satellite with an equatorial orbit around a much larger body with a perfectly uniform gravitational "field"?. Any knowledge or insight you could provide would be much appreciated.


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Re: Does the Moon Rotate?

Unread postby chrimony » Sat Nov 02, 2013 8:52 am

Michael V wrote:Unjustified assumptions, are just so easy, don't you agree?.


Except you're missing the justifications I gave after you claimed I was making an "unjustified leap of reasoning". Justifications that have been given several times earlier. If you had some calculations that you had given earlier to fall back on, you'd have a point.

Whether jtb's alternative explanation of the Moon's rotation/non-rotation is correct or not, I really don't see that the standard explanation is as complete and ironclad as you imply.


So I've gathered, but on the one hand we have Newtonian mechanics, satellites spinning in space as they orbit, and the Earth, Moon, and other planets spinning in their orbits around the Sun, calculated libration effects, and tidal locking, versus... pretty much nothing but busted analogies and "visualizations".

Michael V wrote:
chrimony wrote:I'm suggesting as far as analogous experiments go, the bowls match much more closely to what we see in space than jtb's palm experiment or your ball on a string.

It could be argued that a horse looks more like a elephant than a giraffe does, but it does not follow that studying horses will not necessarily give me more insight about elephants than studying giraffes would. In truth, both are useless as "analogies".


Nonsense. It's Newtonian mechanics. Such analogies and experiments are the bedrock for this field. When we seek to simulate what happens to bodies in space, we try and reduce frictional effects.

You will again notice that I suggested the "piece of string" scenario as a visualisation, not an analogy.


Uh huh, a "visualisation" and not an analogy. Here's the text from your post when you introduced your diagrams (bold mine):

Michael V wrote:This diagram shows that if the Moon were swung round the Earth, as if tied by a piece of string between their centres, then the Moon's famous big black spot would always face Earth.
The Moon would be continuously changing direction, but not rotating.
...
This diagram shows that if the Moon rotates about its polar axis (the small black dot) at the rate of one rotation per orbit, then the big black dot would always face Earth.
The Moon would be continuously changing direction and rotating.
...
So which scenario most accurately describes the relationship between the Moon and the Earth ?.....and why ?.


You can claim you aren't making an analogy all you want, but all I see is backpedaling and a continual refusal to acknowledge basic points. As I said in my last post, this makes further conversation useless. This is the last post for me.

Quite so, I am aware of the "tidal locking" explanation. However, I have read a bit about it, but did not fully understand how it works to produce the single rotation per elliptical orbit claimed for moons. For example, does the moon start with no rotation and acquire rotation, or start with more rotation and loose rotation. Perhaps you would be kind enough to explain.


I'm not interested. Good luck in your research if you really are.

Also, what happens to satellites you mentioned. Why are the spin rates arbitrary?. Do they attain a certain spin rate that stays fixed?, or does it change over time?. Do all satellites spin in orbit if not corrected?. What about satellites in perfectly circular equatorial orbits?. What about an idealised case of a satellite with an equatorial orbit around a much larger body with a perfectly uniform gravitational "field"?. Any knowledge or insight you could provide would be much appreciated.


Again, not interested. Good luck in your research if you really are. I'm satisfied with the standard explanations and evidence. I have seen nothing in this thread to make me doubt them or want to dive in further. If I felt discussion was fruitful and points were acknowledged, I might have been willing to go further.
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Re: Does the Moon Rotate?

Unread postby jtb » Mon Nov 04, 2013 8:13 am

chrimony wrote: jtb wrote:I made some diagrams that explain my position concerning rotation but can't upload them or copy and paste to display. I have them in Powerpoint, Word, pdf, hmtl, and jpeg formats, but can't copy and paste onto this site. The diagrams would probably help you understand my position.

If you have jpegs, just put them on Photobucket or some other free hosting site and link to them.


Thanks, Chrimony. My first attempt so it may be a failure.
Below is (i hope) link to my diagrams.

http://i1294.photobucket.com/albums/b611/jtban/Moon%20Does%20not%20Rotate/Slide1_zps5c359f18.jpg
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Re: Does the Moon Rotate?

Unread postby jtb » Mon Nov 04, 2013 8:23 am

chrimony wrote: jtb wrote:I made some diagrams that explain my position concerning rotation but can't upload them or copy and paste to display. I have them in Powerpoint, Word, pdf, hmtl, and jpeg formats, but can't copy and paste onto this site. The diagrams would probably help you understand my position.

If you have jpegs, just put them on Photobucket or some other free hosting site and link to them.


Thanks, Chrimony. My first attempt so it may be a failure.
Below is (I hope) link to my 3 diagrams.

http://i1294.photobucket.com/albums/b611/jtban/Moon%20Does%20not%20Rotate/Slide1_zps5c359f18.jpg

http://i1294.photobucket.com/albums/b611/jtban/Moon%20Does%20not%20Rotate/Slide2_zpsa7632961.jpg

http://i1294.photobucket.com/albums/b611/jtban/Moon%20Does%20not%20Rotate/Slide3_zps7d25b788.jpg

My conclusion is that since the moon's axis is imaginary, not real like a wheel on an axle, tidal locking is also imaginary or not real.
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Re: Does the Moon Rotate?

Unread postby Aardwolf » Mon Nov 04, 2013 9:25 am

So would Plutonians argue that Charon doesn't rotate, and Charonians argue that Pluto doesn't rotate. Therefore should Earthlings argue that neither rotate...or both?
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Re: Does the Moon Rotate?

Unread postby Aardwolf » Mon Nov 04, 2013 10:09 am

The DODGE satellite stabilised using a gravity gradient technique so I would argue it's the best analogy.

http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1967-066F
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