Why Is The Moon Not Spinning Then?

Billy, you forgot to tell Dwayne to take "common sense seeker" in tow as well.

 

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No, just cautious. He lives and hangs out in another ward, called: http://www.sciforums.com/showpost.php?p=2019716&postcount=35 . I was afraid that Dwayne and Ken would get lost in space if trying to orbit by there first. It is the old 3-body problem. I did not know what to expect except chaos.

 

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Ken. My dear Ken.

Try this little thought experiment.

Imagine you are sitting on the side of the moon facing away from the earth. The stars are bright and steady, yet over a 28 day period they move across your sky. You decide to take a long exposure photograph of the stars and you find that they appear to rotate about a common lunar axis. This is of course, self evident.

From this, you conclude which of the following:

A) The cosmos is rotating about an axial of the moon
B) The moon is rotating about it's own axis.

Or something else?

Your orange-in-hand analogy is completely flawed because your hand is a co-rotating reference with the earth and the orange, err, moon.

The moon clearly does not rotate about an axial reference that is itself locked to the earths axis (your arm and palm in your analogy). However it does exhibit libration, which can only occurr if the rotation of the moon about it's own axis occasionally lags and leads this rotation as it orbits the earth. Otherwise, how do you explain the periodic axial oscillations of something as massive as the moon? By what mechanism does the enormous mass of the moon stop and reverse and then stop and reverse again???

So what are we missing ken? You need to do a better job of explainig why we are all wrong.

Eagerly awaiting some better explanatory discourse from you. Thx.

 

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Well Billy T.
I can not possibly understand what you have said about the lunch bell insitution, i assume that you think that such comments get you some kind of brownie, or other acknowledgement in argument.

Appearantly from the jest of things at conversation, you are determined to uphold your position. Thats fine by me.

The subject of topic was the spin or otherwise no spin of the moon. The moon its motion and other features have been a debate across the world, and new information sparks even newer debates. at one time the moon was thought to be only 116,000 miles away and so on.

For us to consider in argument the spin or not spin of the moon in any account various forces would have to be looked at. So can you define the primary sources to the minium forces in their order of effect, a example would be the sun first, the moon second, the earth third, and any or none of the secondardy forces that effect the motion of the moon.
Because without those assignments really defining the spin motion,liberation, nodulation, apogee become difficult.

Maybe i should look back at what you have written, but i thought you said that the moon rotates around the sun as well as revolves around the sun.

If the moon has a spin axis, it is a spin axis that is in constant motion and in moves in a circle, located in the south east of corner of the moon on the back side of the moon, haveing a near center at the crater Lemaitre
or the crater Minkowski, Give or take some range in direct area.
Such a spin axis is in constant motion around this center point and has covered a wide area in the histroy of the moon, it appears that this axis would have to at this time in lunar history have a wide arc of motion simular to the circle trace out around the celestial pole every 25,800 years.
I think that makes it clear that i will look at the evidence that supports or is relative to your claim of the spin of the moon.


DwayneD.L.Rabon

 

Ok then.

 

C) – The moon is ONLY *revolving* around the combined mass of the Earth and the moon, which is called a *barycenter*. The Earth-moon barycenter is a foci (or axis) which is within the Earth – in this graphic the red + marks the foci of common mass of the Earth-moon barycenter:

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The larger white body (representing the Earth) is also rotating around its polar axis as the moon orbits around the Earth. The smaller white body (the moon) is NOT rotating around its polar axis as it orbits the Earth – if the moon *still* both rotated as it orbited, then we would see more than one face of the moon.

{NOTE – until it was tidally-braked, billions of years ago, our moon did both orbit (revolve) as it rotated around its polar axis.}

If you still don't understand the differences between *REVOLVE* and *ROTATE* (two different types of circular motions), this next graphic shows a sphere *ROTATING* around its internal polar axis:

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---Rotaion & Axis---
"A rotation is a movement of an object in a circular motion. A two-dimensional object rotates around a center (or point) of rotation. A three-dimensional object rotates around a line called an axis. If the axis of rotation is within the body, the body is said to rotate upon itself, or spin—which implies relative speed and perhaps free-movement with angular momentum. A circular motion about an external point, e.g. the Earth about the Sun, is called an orbit or more properly an orbital revolution." (Emphasis added.)

http://en.wikipedia.org/wiki/Axis_of_rotation
--/--

NO, the orange (and your hand) are instead *REVOLVING* 360˚ around the combined mass of your body and orange, and that axis of common-mass would be a foci within your spinning body. The moon's circular motion is exactly the same as our moon's circular motion around the Earth.

The moon does not *ROTATE* around any axis, but the moon does *REVOLVE* around a point exterior to its mass, and the center-point of that orbit is the barycenter within the Earth.

Sloppy verbiage is a sign of sloppy thinking – "The Earth *ROTATES* on its polar axis as it *REVOLVES* around the sun."

If you insist on using "rotate" (which is a circular movement around an INTERNAL AXIS) when the word "revolve" (around an EXTERNAL AXIS) would be a more suitable choice of words, then please do me the courtesy of identifying the EXACT location of the rotation's axis that you're then talking about.

For example, your "B" choice above could mean anything:

superluminal: "B) The moon is rotating about it's (sic) own axis."

If you mean the moon's internal axis, then NO!

If you instead mean the axis of the moon's circular motion is the barycenter within the Earth, then YES!

As I noted early on in this discussion, Libration is interesting, but it has nothing to do with whether, or not, the moon is turning a full 360˚ around its INTERNAL polar axis as the moon also *REVOLVES* (orbits) around the Earth each month.

You could start by polishing up on your English skills in order to correctly use the words "rotate" or "revolve" where suitable.

If you can master English, then we can compare the relevant circular motions involved, from both the sidereal and center-point perspectives, to see how they differ, and then perhaps we can agree whether this is a zero-rotating body, as it's labeled to be (a 0:1 spin rate):

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The moon in that so-called "Zero rotation" graphic is actually *ROTATING* around its internal polar axis clockwise, one time per each counter-clockwise orbit.

Interestingly, the planet Venus' retrograde rotation is only a tad faster than that zero-rotating moon's rotation:

http://www.geocities.com/kfuller2001/tVenus.html

Thus, if Venus continues to slow its rotation due to tidal locking with the sun, then Venus will spin down from its current .93:1 rate (just short of two 360 ˚rotations per orbit) and eventually Venus will slow to a 0:1 spin rate. HOWEVER, since a sidereal spin rate of 0:1 means Venus will still be rotating one time per orbit (as viewed from the sun), Venus will continue to spin down until Venus finally stops at a 1:1 sidereal spin rate.

When Venus finally stops at a 1:1 spin rate (as viewed from the sidereal perspective), the tidal bulges caused by the sun's gravity will finally stop traveling around Venus' circumference and become locked into Venus' surface facing towards the sun. Until that happens, Venus will remain the most perfectly rounded sphere in our solar system. AFTER Venus finally stops rotating at a 1:1 spin rate, at that point Venus will loose its perfectly round shape and form a prolate spheroid:

http://en.wikipedia.org/wiki/Prolate

Ken

 

Pretty graphics, but they are wrong. You need to answer the questions about libration and the angle between the Moon's rotational and orbital planes.

 

Wow. You good at engrish. Still, you wrong. The moon and earth orbit or *revolve* about their BC, and they also bothe *rotate* about their own axes of *rotation*. You just don't have the intellect to grasp such a simple concept.

Wow. That pretty good.

YES, the orange is *REVOLVING* about your head, but is also *ROTATING* about itss'ss own axis of rotation. If the earth suddenly disappeared and the moon went on about it's's's's tangential path, it would still *ROTATE* once in approximately twenty eight days.

This is moronic.

Sloppy thinking is one sign of a moron.

"The Moon *ROTATES* on its polar axis as it *REVOLVES* around the earth." only at a rate equal to its's's's orbital period.

YES! Then how do the stars appear to *ROTATE* about the moons's's's polar axis as seen from the moon itself?

Every "ken" I've ever known has been a dick. The trend continues...

If you can suck your own dick, then you can compare the relevant sucking styles of you and all your boyfriends.

http://www.jimloy.com/astro/moon0.htm

http://www.newton.dep.anl.gov/askasci/env99/env093.htm

http://www.physlink.com/education/AskExperts/ae390.cfm

http://wiki.answers.com/Q/Does_the_moon_rotate_on_its_axis_like_a_planet_or_does_it_just_revolve_around_Earth

http://www.badastronomy.com/bad/misc/tides.html

So, despite all of this, you will, of course, continue to "believe" that the moon does not *ROTATE* about itssss own axis (even though it's must) as it'ss's *REVOLVES* around the earth.

Now, as a dick, you probably don't realize just how many people, including grade school students, are laughing at you. I however, realize that there is a mental disorder that limits the ability of certain people in visualizing certain kinds of motions. You clearly have this disorder, and I feel for you. But only a true dick such as yourself ignores the counsel of so many others on such a simple topic. Just as a color-blind person constantly insisting that apples are blue, when corrected by fully sighted persons, is a dick.

So, kendick, I will leave you to your auto-oral pursuits and masturbatory fantasies about *ROTATING* objects.

its, it's, it has, itsh, been fun.

 

I agree on need to use terms correctly but your physics about moon’s rotation or spin being zero is wrong, still.

I will use “spins” to more compactly state: “*ROTATES* on its polar axis” for rigid bodies, like the moon. (Spin is more general than that as an ice skater can “spin” without any “polar axis.” In general “spin” just means to present different aspects of the spinning object to many observers in different locations that are relatively fixed wrt each other, even if separated by great distances as the "fixed stars" are. These observers can be in ANY non-rotating frame but locations near the polar axis extended see only very small changes in the surface of the spinning body. For them it is almost a "pure spin" view.)

Spin is most easily (and only way for rigid body)* detected by an observer fixed on the body that may be spinning by observing these “fixed objects” APPEAR to rotate about extension of the polar axis. For example someone in the USA can photograph all the stars rotating about point near Polaris star (and here in Brazil they APPEAR to rotate about point in the “Southern Cross”) and confidently conclude the Earth is spinning about a polar axis which is extend approximately between Polaris and the Southern Cross. Likewise if observing from Venus, one could confidently conclude that Venus is spinning about its polar axis which if extended passes near the stars Vn and Vs (I do not know their names, so assigned these symbolic ones.) In fact EVERY planet, MOON, and asteroid, with name “X” is spinning about its polar axis which is approximately line between stars Xn and Xs.

How can I be so sure that EVERY one is spinning about some polar axis? Well the answer is very simple: The fraction of possible “spin space” with EXACTLY zero spin rate has, to use mathematical terms, “zero measure.” I suspect that in our solar system there may be some bodies that have very small, but non-zero spin rates. Perhaps not even one complete turn wrt the fixed stars even in 1,000,000 years, but they are still spinning. What you are asserting is that the moon is an exception to this, even though a “moonman” could photograph the APPEARANT circular movement of the stars and see that the center of these circles passes very near star Mn (when he takes picture from the northern hemisphere) and about Ms (when photographing from the southern hemisphere of the moon)

Please note that Mn is about 7 degrees displaced from Polaris and likewise, Ms is displaced about 7 degrees for the point in the Southern Cross the Earth’s polar axis passes thru. That is to say that the polar spin axis of Earth and Moon are two non- parallel lines in space , call these lines E & M. Any line passing thru a point on E and parallel to M is inclined about 7 degrees to line E.

If you find any error in this post please tell me where it is. Also please explain why the moon is the only body in the entire solar system NOT spinning on it polar axis, as has been EXPERIMENTALLY CONFIRMED for Earth, Moon and Mars, by photographing the APPEARANT rotation of the fixed stars with time exposures.

You were a fool not to follow the advice I gave you following your first erroneous post, suggesting that you quickly stop your nonsense and thank those correcting you.
----------------------
*If not aided by some instrument, but as you pointed out, the Foucault pendulum can also be used to detect the spin about the polar axis. Then in embarrassment about shooting yourself in the foot, you quickly asserted that the Foucault pendulum was not known to turn relative to the moon’s surface. (I had to admit that it never had been observed.) Your stupidity and stubbornness will no doubt also allows you to also state that a time exposure photographing fixed stars made on the moon will NOT have the circular star tracks as that also proves the moon is spinning about its polar axis. The rate of turning of the Foucault pendulum is identical with the apparent rate of fixed star movement if the Foucault pendulum is set up on either pole of the body being tested for spin. I.e. two independent measurements both can confirm the SAME spin rate for the moon.

Again, of all the fools active here you are the clear leader, both in stupidity and stubbornness! But you can insert drawings, which for some unknown reason I cannot.

For non rigid body, with significant spin rates or very small masses, the polar axis spin can in principle be detected by the near parabolic surface shape of liquid surfaces. If spin rate is low or body is too massive then on surface of the body, the curved liquid surface will be nearly spherical and it is not practical to move to the center of mass to eliminate this gravitational effect.

 

Each planet & each moon in this solar system except our moon does something which our moon does not. In the universe I lived in until recently, it was called rotating. Evidently, you don't want to call it that. WHAT do you want to call it???

 

I like to call it 'turning on its axis', but 'revolving as it orbits' does the trick too.

It (our moon) also spins, once for each orbital rotation, how about that?

 

More of the same doubletalk BS.

 

List of Known Tidally Locked Worlds

From Wiki;
Solar System
Locked to the Sun Mercury (in a 3:2 rotation orbit resonance)

Locked to the Earth Moon

Locked to Mars Phobos Deimos

Locked to Jupiter Metis Adrastea Amalthea Thebe Io Europa Ganymede Callisto

Locked to Saturn Pan Atlas Prometheus Pandora Epimetheus Janus Mimas Enceladus Telesto Tethys Calypso Dione Rhea Titan Iapetus

Locked to Uranus Miranda Ariel Umbriel Titania

Locked to Neptune Proteus Triton

Locked to Pluto Charon (Pluto being itself locked to Charon)

Extra-solar Tau Boötis is known to be locked to the close-orbiting giant planet Tau Boötis Ab.

 

Interesting. As both are small (low gravity) we could connect them with cable I bet, if anyone can think of a reason to.

Here is one for the 22nd or 23d century:
After we have them connected, we just slightly winch them closer together. As both are spinning about their polar axis and we have slightly changed the orbit period about the barycenter, the cable will wind up on them and their mutual orbit period will decrease more – a self accelerating process. The cable was designed not to break before Charon has Pluto's and solar escape velocity. If we cut the carbon fiber cable at just the right time, Charon with its installed nuclear reactors etc. for energy can be humanity’s interstellar spaceship to colonize some other star’s planet. There should be enough mass for the rail gun launchers to guide it to the desired planet or one of its moons. Farfetched, yes, but about the only way humans will get there.

Have any better ideas?

 

No. Can't think of a good reason, but the idea appeals.
Must be useful for something or other.

 

It rotates once a DAY! Gee, guys, nobody corrected this yet??? Thread is too long to read it...

 

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Ophiolite is going to fry you alive when he reads this.

 

Should we post under the language forum the non-difference between rotation and spinning?

Anyway, the real reason is for that, because there is an alien observatory on the moon and this way they only had to build one...

 

technically, it takes the moon about 27 days to rotate around the earth once??? not exactly sure, correct me if im wrong... which means it would take 27 days for it to make one full spin along its axis, (much like pluto and one of its close satellites charon)

this is known as a 1:1 spin-orbit coupling ratio... look it up if you still dont think the moon both rotates and spins