Moon rotation: forget empiricism, use geometry.

[anditopens]

Empirical reasoning is so misleading that one is never certain of its conclusions even after a long series of debates. However, the many discussions on the web concerning the Moon rotation are all empirical. To quickly get an answer acceptable to all (is the Moon spinning or not?) it is necessary to use a scientific tool. I would propose to use the simplest of all: the geometry of Euclid. In a first purely mathematical step we analyze the rotations in the plane of a disk around itself and around an external point. In a second step the conclusions drawn from the first step are applied to the real case of the Moon.
The reasoning can be read at the site "yellow moon rotation", more precisely at the page https://yellow-moon-rotation.com/sci...-yellow-scale/ of the said site and still more precisely at the 2 chapters of the said page titled degree 1 and degree 2.

[PetersCreek]

Welcome to the CosmoQuest forums, anditopens. Before you proceed with your thread, please read our rules which linked in my signature line below. I also recommend that you read our ATM forum advice, also linked. You are welcome to use your off-site materials for brief, specific references but the bulk of your claims must be presented here, in this forum. "Go read my paper" isn't allowed.

[Jens]

Anditopens, sorry if this is a little bit obvious, but to do an actual measurement, wouldn’t it be fairly easy to put a camera on the moon and see whether it is always looking at the same stars or not?


Sent from my iPhone using Tapatalk

[Van Rijn]

Anditopens, sorry if this is a little bit obvious, but to do an actual measurement, wouldn’t it be fairly easy to put a camera on the moon and see whether it is always looking at the same stars or not?

Even from Earth, you can watch the sun move across the lunar surface, which clearly indicates the moon rotates with respect to the sun. Anditopens, could you present your argument here? Are you claiming the moon doesn’t rotate with respect to (for example) the sun? Because if so, that’s obviously wrong.

[21st Century Schizoid Man]

I'm a little bit confused here.

So you're going to prove that a physical object is or is not spinning using the axioms of Euclid?

But, if you're not using empiricism, then I'm not sure why this statement appears in the analysis.

We have known for centuries that the Moon always presents us with the same face, or, to put it another way, the same point B.

That sounds like empiricism to me.

[Torsten]

Hi and welcome anditopens,

Perhaps you could simply paste the argument from your page into a post to meet the requirements that it be presented here.

However, I've looked at your argument. Consider your figure "ys1" in section Degree 1.2: Particular case (simple rotation). If the disc does not spin, then vector M₀B₀ must be parallel to vector M₁B₁, and it is not.

I think it's as simple as that.

[anditopens]

I'm so sorry PetersCreek. I've already got 5 responses. I am waiting for your green light to reply. If you agree I will then reply the same for them all: "You are trapped by empiricism. The first thing to do is to show the whole degree 1 to as many teachers in mathematics as you know and ask them if they find a single error in it. Don't mention the Moon."

[PetersCreek]

I'm so sorry PetersCreek. I've already got 5 responses. I am waiting for your green light to reply.

Anditopens,

You may reply to the previous posts but as I wrote, you must make your case here, in the forum. Further, please do not reply to moderator comments within the thread unless specifically asked to do so. If you need clarification, please use the report button (see below) which will bring your question to the attention of the moderation team or you may PM me or any moderator directly.

[profloater]

This surely is about words not geometry? If you eliminate the Earth and consider the moon against fixed stars, it rotates about an epicentre. That epicentre is on the line joining the moon and Earth centre. Whether you call that spin is a definition of the word spin that is not fundamental geometry. If you call the motion an orbit around that epicentre that defines orbit. The motion relative to the sun is epicyclic with geometric centres at the sun and the Earth . In dealing with epicyclics you choose an arbitrary useful centre and fix that as a reference to analyse the motions of the “mechanism” if you choose to fix the moon the Earth is stationary but spinning while the sun orbits around the moon and so on. If you fix the Earth the moon is spinning and orbiting at the same rate. that is the normal observation empirically too.

[Reality Check]

Empirical reasoning is so misleading that one is never certain of its conclusions even after a long series of debates. However, the many discussions on the web concerning the Moon rotation are all empirical. To quickly get an answer acceptable to all (is the Moon spinning or not?) it is necessary to use a scientific tool. I would propose to use the simplest of all: the geometry of Euclid.

Hi anditopens and welcome to the forum.
The major problem with your idea is that it has already been done. Isaac Newton explained the orbit of the Moon using Euclid geometry and gravity. Another problem may be that if your idea ignores gravity, the Moon cannot orbit the Earth. Hopefully you will explain your idea more fully.

[Nikolay Sukhorukov]

As far as I understand, any rotation is first of all movement, and only then geometry. But movement is kinetic energy. The rotation of the Moon around the Earth is obvious. For example, if the Moon, revolving along its orbit, will gradually approach the Earth and crash into it, energy will be released. But with the rotation of the Moon around itself is not so easy. Does an artificial satellite revolve around itself after initial orientation to the Earth? If no energy is used to maintain the initial orientation, then the satellite is probably not rotating. Its apparent rotation relative to the Earth is a geometric illusion. The same reasoning may be applied to the Moon.

[anditopens]

I am not questioning the rotation of the Moon around the Earth but its rotation on itself (spin) only.
I'm sorry I couldn't paste degree 1 and degree 2 of the yellow scale, I got only an HTML text with beacons and no figure. I'm afraid you will have to go to
https://yellow-moon-rotation.com/sci...-yellow-scale/

Because of the general confusion I propose in the first instance to focus only on degree 1. So the only question is: is there a single error in degree 1?
So far I have only received one answer on degree 1. It is from Torsten (#6). Please have a look at it.

[anditopens]

I would say this is not empiricism this is observation.
Because of the general confusion I propose in the first instance to focus only on degree 1. So the only question is: is there a single error in degree 1?
So far I have only received one answer on degree 1. It is from Torsten (#6). Please have a look at it.

[anditopens]

I'm sorry I couldn't paste degree 1 and degree 2 of the yellow scale, I got only an HTML text whith beacons and no figure. I'm afraid you will have to go to
https://yellow-moon-rotation.com/sci...-yellow-scale/
Because of the general confusion I propose in the first instance to focus only on degree 1. So the only question is: is there a single error in degree 1?
You say: "Consider your figure "ys1" in section Degree 1.2: Particular case (simple rotation). If the disc does not spin, then vector M0B0 must be parallel to vector M1B1,....".
I answer: "No. the vector M0B0 cannot be parallel to vector M1B1 because the vector MB, "engraved" on the disk, rotates around the point E as does the disk".

[tusenfem]

I'm sorry I couldn't paste degree 1 and degree 2 of the yellow scale, I got only an HTML text with beacons and no figure. I'm afraid you will have to go to
https://yellow-moon-rotation.com/sci...-yellow-scale/

Dear anditopens
I am sorry but that kite does not fly.
On the website you can right click the figure and save it and then upload it here on CQ.
Also explanations can be copy-pasted here.
The rules of ATM state clearly you will have to present your stuff here and not on an external site.

[anditopens]

You are addressing the delicate problem of the reference frame. It could be debated a lot, well beyond my skills. What I can say is: if you question that of my site you will have to question that of many astronomers" sites dealing with the subject, such as https://svs.gsfc.nasa.gov/4709 or https://en.wikipedia.org/wiki/Tidal_locking.
Anyway, I suggest to drop this problem for the time being in accordance with my proposal:
"""Because of the general confusion I propose in the first instance to focus only on degree 1. So the only question is: is there a single error in degree 1?
So far I have only received one answer on degree 1. It is from Torsten (#6). Please have a look at it."""

[anditopens]

I agree that in astronomy all derives from observation and dynamics: in descending order kinematics first and then geometry. However nothing could justify a violation of basic theorems of geometry allied to universally admitted observation. I'm only stating that there is such a violation, I'm totally incapable to say why. The only way I can see to rectify the situation is to admit that the Moon doesn't spin.
But for the moment I think preferable to consolidate the foundation according to this:
Because of the general confusion I propose in the first instance to focus only on degree 1. So the only question is: is there a single error in degree 1?
So far I have only received one answer on degree 1. It is from Torsten (#6). Please have a look at it.

[anditopens]

OK tusenfem, I'll do my best. It should work if I do it paragraph by paragraph, figure by figure. Has anyone a suggestion for pasting directly documents from a WordPress editor to a CQ one?
If I succeed I post it as a reply to your thread tusenfem #15, degree 1 and degree 2 only, without any text of my initial thread, on the 25 of February unless an advice from you in the mean time.

[PetersCreek]

anditopens,

I've warned you not to reply to moderator comments within this thread, unless specifically asked to do so. I will send you a PM (private message) about your question.

[Reality Check]

I am not questioning the rotation of the Moon around the Earth but its rotation on itself (spin) only.
I'm sorry I couldn't paste degree 1 and degree 2 of the yellow scale, I got only an HTML text with beacons and no figure. I'm afraid you will have to go to
https://yellow-moon-rotation.com/sci...-yellow-scale/

Because of the general confusion I propose in the first instance to focus only on degree 1. So the only question is: is there a single error in degree 1?
So far I have only received one answer on degree 1. It is from Torsten (#6). Please have a look at it.

My answer is that drawing figures says nothing about whether the Moon rotates or not. There is no point in looking at figures when we can look at the Moon and apply geometry to what we see!
Physics says what rotation an orbiting body can have. Planets, moons, etc. can have any rotation subject to the influence of other bodies. The Moon rotates because it is tidally locked to the Earth. This is an empirical observation. The Moon presents the same face to everyone on Earth. To do that it has to rotate. Think about Alice and Bob on opposite sides of the Earth. They both see the same side of the Moon. The Moon has to rotate 180 degrees to show Bob the same side as Alice.

[stutefish]

Rotate relative to what?

[Reality Check]

Rotate relative to what?

If this is a question for me: Rotate relative to us and just about everything. The exception is an observer rotating in the opposite direction to the Moon with the same rate.

[anditopens]

My answer is that drawing figures says nothing about whether the Moon rotates or not. There is no point in looking at figures when we can look at the Moon and apply geometry to what we see!
Physics says what rotation an orbiting body can have. Planets, moons, etc. can have any rotation subject to the influence of other bodies. The Moon rotates because it is tidally locked to the Earth. This is an empirical observation. The Moon presents the same face to everyone on Earth. To do that it has to rotate. Think about Alice and Bob on opposite sides of the Earth. They both see the same side of the Moon. The Moon has to rotate 180 degrees to show Bob the same side as Alice.

You say: "when we can look at the Moon and apply geometry to what we see!". It is exactly what I propose. Concerning observation: we all agree (me included, I reassure you) that the Moon presents always the same face. Concerning geometry could you please show yours, that is: figure(s) with center(s) of rotation and angles + explanations?
Concerning the rest of your message: I stick to my proposal to parse degree 1 only first. A little derogation: the above mentioned observation of the Moon is at the heart of the link between degree1 and degree 2 .

[anditopens]

Rotate relative to what?

I suppose your question is about the reference frame, If it is, please refer to #16, which is in fact my reply to profloater #9. If it is not, could you please be more specific?

[tusenfem]

You say: "when we can look at the Moon and apply geometry to what we see!". It is exactly what I propose. Concerning observation: we all agree (me included, I reassure you) that the Moon presents always the same face. Concerning geometry could you please show yours, that is: figure(s) with center(s) of rotation and angles + explanations?
Concerning the rest of your message: I stick to my proposal to parse degree 1 only first. A little derogation: the above mentioned observation of the Moon is at the heart of the link between degree1 and degree 2 .

Okay, that is enough, you cannot ask another CQ-pian to show figures etc. and not do so yourself.
First you will define HERE on CQ what exactly "degee 1" is, which YOU HAVE STILL NOT DONE even though you were told to present your stuff here.
Then you will describe what "degree 2 " is here on CQ, and you will post your figures.
Do not comply and you will receive an infraction.

[Van Rijn]

I suppose your question is about the reference frame, If it is, please refer to #16, which is in fact my reply to profloater #9. If it is not, could you please be more specific?

Your post 16 links to this NASA page which has a short comment on the Moon’s rotation:

https://svs.gsfc.nasa.gov/4709

Which says:

An enduring myth about the Moon is that it doesn't rotate. While it's true that the Moon keeps the same face to us, this only happens because the Moon rotates at the same rate as its orbital motion, a special case of tidal locking called synchronous rotation.

(It also includes a short video to illustrate and another sentence commenting on it.)

It seems to contradict your position and seems an obvious point to me. With or without Earth, the Moon can be seen to rotate. If you have an argument countering that, then please present it here.

Incidentally, while the Moon does mostly keep one face towards Earth, we can still see about 59% of the lunar surface from Earth due to libration, as shown here in this gif file:

https://en.wikipedia.org/wiki/Librat...uous_loop).gif

Note too that sunlight can be seen moving across the Moon’s surface, an indication of the Moon’s rotation with respect to the sun.

[bknight]

In addition why do you suppose that the Chinese lander/rover go into hibernation every +/- 14 days? It because the equipment is in Lunar night, because the Moon rotates.

[pzkpfw]

Well (though I should not have had to) I've looked at "degree 1" and certainly think it's wrong.

It's clear to me that if disc D were not rotating about its own axis, the line M-B would remain in the same direction, i.e. M1-B1 would be clockwise from M1-E.

The reason M1-B1-E stay in alignment is exactly because a non-zero b exists, that acts to cancel out a.

I think your (unattributed) reply to Torsten shows where you go wrong:

...
I answer: "No. the vector M0B0 cannot be parallel to vector M1B1 because the vector MB, "engraved" on the disk, rotates around the point E as does the disk".

This "engraving" is about you combining the "cause" of the orbit of the moon with it's own rotation.

e.g. Put a sheet of paper on a table. Put a coin at the edge of the paper, and your finger at the centre of the paper. Rotate the paper around your finger with your other hand.

Yes - one side of the coin always stays facing your finger. But that's because the paper is causing the rotation and locking the facing of the coin to the finger. (This is in effect your "engraving".)

In space, that locking does not exist (unless you also plan to invent a whole new understanding of gravity). The orbit of the Moon around Earth (well, look up "barycentre") is separate to its rotation.

To see this in your geometry: Try re-doing ys1 and ys2 with another Disc added, where E is at the centre of that disc. Now put a "C" on the edge of that new disc (like the B on the edge of M). Now do your rotation. Where is "C" facing now? And does that match what we see between Earth and the Moon?

To see the separation of effects:

Hold a coffee cup in your hand. Hold your hand out and slowly spin. Yes, the facing of the cup to you is always the same - but that's because your arm is making the cup orbit you and locking its spin. Now put water in the cup, and something floating in it to see the movement (rotation) of the water. Now spin yourself again. Until water-cup friction eventually makes the water "tidally lock" to you, you'll note that the water keeps its orientation with the room - it's not spinning.


Your geometry does not accurately model reality.

(You are modelling an orbit as a rotation around a centre. But it's more a translation - following the path of an ellipse.)

[VQkr]

We see where the OP went wrong in their "section 1":

SOC 1.1: If (D) rotates by an angle a around E and by an angle b around its center then the vector MB rotates by an angle a + b.

This is incorrect, because an object rotates around its center of mass. An object cannot "rotate...around E". All the conclusions in the later sections stem from this error and are also therefore flawed.

They are confusing the moon's roughly circular orbit, its translation, with a rotation. The moon does not rotate around the earth, it orbits the earth (more technically, the earth-moon barycenter). If the moon did not rotate, observers on earth would see the entire surface of the moon over the course of its orbit. But due to tidal locking, the moon does rotate with the same period as its orbit.

It might be worth noting that while position and linear velocity are relative terms (they must be referenced to something else to be meaningful), rotational velocity is absolute: an object can be said to be rotating or not rotating without referencing anything else. And the moon most certainly rotates.

[PetersCreek]

This thread is closed due to non-participation by the OP and failure to provide timely answers in spite of moderator instructions. This topic may not be revisited without prior approval from the mod team.