Why Is The Moon Not Spinning Then?

Discussion in 'Pseudoscience Archive' started by common_sense_seeker, Sep 6, 2008.

  1. Vkothii Banned Banned

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    But the moon isn't rotating on it's own axis? It's rotating on a 'different' one?
    Of course it's relative to the sun, so is the earth's rotation - however both bodies have "rotations" wrt each other. It's how gravity works - you need 2 bodies with mass, right?

    You have to explain how come we don't see the entire surface of the satellite.
    If it didn't rotate in two different ways, we would. It rotates around the earth (that's one of the motions it can have).

    If the moon had no other rotation, like all bodies moving through space have, we would see the entire surface. We don't see the entire surface, though.

    Why not?
     
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  3. D H Some other guy Valued Senior Member

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    It is rotating on its own axis. The motion of any solid body can be described as a rotation about an axis passing through the body's center of mass and and a translation of the center of mass. This is simple geometry: Euler's fixed point theorem.

    You are confusing rotation and orbital motion (or orbital revolution). Rotation is the motion of a body about its center of mass, while orbital revolution is the translational motion of the body's center of mass.

    You once again are confusing rotation and revolution.

    Believe it or not, the Earth is not the center of the universe.

    Look at it this way. Suppose you are speeding along some highway. You drive past another vehicle with a relative speed of 15 miles per hour, at which point the other vehicle turns on its pretty red and blue lights. The judge will not accept your argument that you were only going 15 miles per hour.
     
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  5. Ophiolite Valued Senior Member

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    I have absolutely no problem with people who don't understand basic facts about some aspect of science. And we are all there for most of science. I do have a problem when someone listens to the explanation then declares, for no good reason other than incredulity, I don't believe it. And then maintains that position in the face of everything.

    In this thread the only way to describe it is lunacy.

    Time for a lockdown..........pretty please.
     
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  7. Vkothii Banned Banned

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    D H, you are confusing a pedantic obsessive condition with correcting an invalid argument.

    You cannot possibly present a logical argument that supports a single thing that you attempt, and fail utterly, to refute. The earth is the centre of the universe for the moon's gravitational potential.

    Notice how there's 1 moon and 1 earth, which makes 2 bodies, as I say above? Did you work out that they both have two kinds of motion, as I also say, and you then appear to repeat, apparently confusing the idea of "one kind of motion" with some other thing?
     
  8. cluelusshusbund + Public Dilemma + Valued Senior Member

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    Well Ken Dine... sinse you finaly seem to except that the hammer does rotate... can you relate the hammers angular momentum to the moon... an understan that the moon also has angular momentum cause it also rotates on an internal axis.???
     
  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    cluelusshusbund's quote of Ken Dine's post includes Ken's observation (from two different cameras, one at ground level near the toss-site; the other from high up in the stands looking down on the landing ball with its attached chain), which were directed at me.

    Yes, it is true that film from one camera shows clockwise and the other counterclockwise rotation, as if angular momentum were not conserved.

    I again note that this is a false conclusion is caused by camera perspective change. To easily understand, imagine you had a completely transparent but otherwise normal clock laying face down on the floor. From you POV, standing above it, its hands are moving counter clockwise.

    Whenever you switch the side from which you are observing the rotation from, clockwise and counter clockwise reverse with no change in the actual rotation.

    The nature of the moon's rotation is not the only thing Ken does not understand. Rather than thank the many who tried to help him, Ken just went away after post 109. (Another mistake, IMHO.) Perhaps he will come back when more mature. He did know some things.
     
    Last edited by a moderator: Feb 19, 2009
  10. cluelusshusbund + Public Dilemma + Valued Senior Member

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    Over a period of mor than a year... me an several others have thoroughly discussed the moon rotaton issue wit Ken Dine (in 4 diferent groops that i know of)... an as you have observed he seems dead serous about his moon ideas... hes college educated an knows lots of thangs... but when it com to the moons rotaton... even a 9th grade dropout (as he refers to me... lol) such as myself can understan synchronous rotaton... an that the latitude an longitudinal libration of the moon which we observe from earf coud not occur unless the moon rotated on an internal axis.!!!

    I even preformed an esperiment in which i atached a strang to an object an swung the object in a circle overhead an then released the strang... an no mater what object i used (tennis ball... steel pipe... ect)... when i released the strang the object flew off in a strate line but it also rotated on its axis... an he rejected my results as a faulty esperiment... an his evidence that my esperiment was faulty was that video of the Russian hammer thrower... in which he said the hammer clearly does not rotate when released.!!!

    But i tell you what... not only has learnin about the moon an doin the esperiments been interestin... its also been interestin watchin an educated man reject all reason about the moons rotaton.!!!
     
  11. geistkiesel Valued Senior Member

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    2,471
    [index]
    Is the angular momentum loss by earth measured or calculated from theory? If you have a reference I's like to see it.
    Question I: I don't question your math or physics but I do wonder what the mechanical link might be such that the transfer of energy from earth to moon directly affects the moon's rotational velocity or results in a new orbit trajectory. Energy being a scalar it isn't obvious to me how a transfer of energy can alter the orbit or rotation unless the energy transferred is "directional" in some way. I was on another mission when I bumped into this thread. I had just been locked out of a thread regarding the Shell theorem and the gravity topic caught my eye.
    :shrug:[/index]
     
  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    I think I know the answer to your question. The Earth is not a rigid body. The moon's gravity gradient cause tides, which are bulges of mass that tend to keep their same relationship to the moon. Think of them as fixed relative to the moon and Earth rotating under these bulges. There are different land masses spinning underneath these bulges so they cannot keep exactly the same relationship, but this is not important if we think of their long term average.

    Now to make it more clear, lets conceptually divide the Earth into two parts: One is a perfect rigid sphere and the other, to be extreme in our model, is just a dumbbell, (rotating with the Earth's 24hour day but fixed wrt the moon, representing the tides).

    I will type draw the dumbbell as: #----------#

    And the moon as: O

    This crude arrow:
    ^
    |
    |
    indicates the moon's velocity.

    Now because I think you will agree that the rigid sphere part of the Earth cannot accelerate the moon, to change it orbit, even if it is spins, let’s ignore it. I.e. all of the moon's orbit change must come from the dumbbell, but it is not spinning when viewed from the moon. Wobbling a little bit, due to the effect of the land masses the tides encounter but I will make discussion simpler by having a model of Earth where there is no land mass - just a uniformly deep single ocean covering the Earth. Most of this ocean water is also spherical, so it too can be ignored as not able to change the moon's orbit.

    SUMMARY (thus far): Only the tidal dumbbell is available to change the orbit of the moon and your question is how does it do it? What is the mechanism?

    If the spatial fixed relationship of the moon and dumbbell were like this:


    ^
    |
    |

    O...........................................................................................................................................a#----------#b

    where I have separately labled the two masses of the dumbell for later reference. (Ignore the ........... as they are needed to keep Sciforum's computer from compressing many spaces down to only one.)

    Then the dumbbell also cannot change the moon's orbit as 100% of the forces from both of the # masses acts only along the line from Earth to Moon; Helping make it orbit the Earth. (Moon's velocity turning clockwise in my typed drawing but not changing in speed.) However, that is not their spatial relationship to the moon because it takes some time to lift up a tidal bulge. I.e. the max tide is NOT on the Earth / moon line but delayed. I.e. the near moon bulge peak is a little west of the Moon Earth line as seen from the moon. (The moon is traveling Eastward. I had to give the view as if seen from far below the south pole as I needed a point for my arrow and only the ^ is available.* Thus, in this "southern view," drawing the Earths spinning surface and the moon are going "clockewise.") Thus the typed drawing should be more like:


    ...........................................................................................................................................................................#b
    ^
    |
    |

    O



    .................................................................................................................................................................a#

    Recall the crude arrow pointing up above the moon indicates the moon's velocity. Also note the delay required for the bulge to reach its peak and Earth's rotation have rotated the dumbbell counter closkwise wrt the first drawing's in line position ( a#----------------#b )

    Now I need not show the dumbbell’s bar -------------- to keep them apart and it would be hard to get correct even if I used: / to make a sloped line between the two #s because what I type on my computer displays very differently when posted.

    Also imagine that the two #s were about 100 yards more to the right and thus both making a very small angle triangle with the moon at the apex.
    The scale here is very wrong as the distance between the two #s is the Earth's diameter and the ....... needs to be very much larger as it is the moon Earth separation. I.e. both #s are only a small angle off the moon Earth, center to center, line with the near one's peak displaced a little west of the Earth moon line.

    Now both of the #s do exert a force on the moon in the direction of its travel. The more distant # is trying to speed moon's velocity and the closer # is trying to slow it down. Because the closer one has the stronger force, it wins and the moon's velocity slows down.

    With this slower velocity the "centrafugal force" is less so to still be in a circular orbit that is stable the moon must be in weaker Earth's gravity (or further away). BTW please note that there is no such thing as "centrafugal force." - It just feels that way on a merry-go-round, etc.

    Initially it seems this is wrong as Janus said the Earth was transferring energy to the moon (and that is true) yet I am claiming the moon is slowing down! I.e. that the moon's kinetic energy has Decreased!

    Resolution of this paradox requires a little more understanding of orbits. I.e. the moon is in a gravitational well made (by the Earth). It takes energy to climb partially out of that well and be further away. I.e. the Moon gained Potential Energy, PE, and lost Kinetic Energy, KE is the answer to the paradox. Here it is in detail:

    Well it turns out that the total Energy, E, is negative for any bound orbit (that is what "bound" means.) and for circular orbits the magnitude of the PE is twice that of the KE. So to make this very clear I will switch to a numerical example with the moon assumed to be in a circular orbit (to keep it simple):

    A long time ago when the moon was closer and more tightly bound to the Earth, here is the "energy story":

    E = -51 = PE + KE = -102 + 51

    Now the Energy story is:

    E =-50 = PE + KE = -100 + 50

    Note that the moon, now farther away, is only 50 energy units bound. I.e. it is escaping from the Earth's "gravity grasp" and has gained one unit of energy (from the Earth's spin - The days are getting longer.). The moon has move up out of the potential well by 2 units of energy and lost one unit of kinetic energy.

    I hope and trust you now understand both the mechanism and that energy are being transferred to the moon, despite it slowing down.

    You may not know that Pluto is going slower than the Earth. But this follows from Keppler's law that the square of the period is proportional to the cube of the orbit radius (actual the semi major axis of the ellipse, but I am sticking with circular orbits to keep it simple.) I will write that as:

    T^2 ~ R^3 although instead of R one traditionally uses "a" for the semi major radius)

    Thus if R were doubled, then T is 2(square root of 2) or more than doubled.

    Yet the circumference around the twice larger orbit is only doubled. I.e. it takes more than twice as long to make the full trip around but the path around has only doubled. Thus, the planet (or moon) must be going slower in the larger orbit.

    I.e. the whole "story" is consistent and here is a quick summary:

    Because the two tides are not on the Moon / Earth line and the near to moon one is making a stronger force on the moon than the further one and a component of that force is slowing the moon down the moon is moving to a more distant orbit and the day is getting longer. There is energy being transferred to the moon, two units of which are decreasing the negative potential energy and one unit is decreasing the positive kinetic energy for a net transfer to the moon of one positive unit of energy, which previously was in the rotational energy of the Earth's spin.
    ---------------
    *I could have given a view from far above the north pole if I had put the moon on the right edge of your screen, and then that same "up arrow" would give counter clockwise rotations one often sees in such drawings, but that is very hard to get correct when typing and using ............ to defeat the sciforum's computer compressing spaces down to only one. The V could have been used as the arrow point down instead of up and keep the moon O at the left edge still but I could not get it to center on the | line. Besides I live in the southern hemisphere now so it seems OK to me.

    Please Register or Log in to view the hidden image!



    PS I am sure Janus 58 could explain it perfectly with 1/10 the words but some people may follow a long winded and detailed version better.

    -----------------
    On your first question: What is measured is the slowing of Earth's spin and the increasing in the Earth moon separation. (Two independent measures that agree but either could be used to calculate the other - so this is a very good test.) I imagine by assuming perfect consevation of total angular momentum this data allows a good measure of the Earth's moment of inertia to fall out.

    The laser retro-reflectors left on the moon and very brief (or modulated for precise time ref) laser reflections lets one measure the earth moon separation.
    The cumulative change in the spin rate times the total time lapsed (an angle) is best measured, I think from old total moon eclipses. For example, assume there is a constant spin, rate and calculate in which Chinese city an ecllipse of ~3,000 years ago was visible. Well it was not seen there, but in a citry X miles to the west according to the temple astronomers records and local stories of dragon that ate the moon etc.

    From X and the radius of the Earth, you get the "correction angle" the Earth failed to rotate thru in these 3,500 years because it has not been spinning at a constant rate, but slowing.
     
    Last edited by a moderator: May 7, 2009
  13. AlphaNumeric Fully ionized Registered Senior Member

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    Gravity is a force, it is vectorial. A transfer of momentum, linear or angular, results in a change in energy. It is not that the energy of the Moon somehow increases but nothing else changes, there's a corresponding change in angular and linear momentum, both in terms of the Moons orbital angular momentum and its rotational angular momentum.
     
  14. common_sense_seeker Bicho Voador & Bicho Sugador Valued Senior Member

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    I agree geistkiesal. Where's the references? There's even enough dispute to suggest that Mercury's 'anomalous' precession could be due to tidal interactions, it having the slowest rotational speed of all the planets: The Rotation of Mercury. Maybe there's another alternative to Einstein's "fabric", his vision of spacetime has yet to be confirmed by LIGO.
     
  15. AlphaNumeric Fully ionized Registered Senior Member

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    Shouldn't you have been taught such things during your astronomy degree? Once again you complain that you don't know something you should. You really wasted those years in uni, didn't you?

    No, what you mean to say is that you've found a website which supports your baseless claims about something you don't understand. You say 'there's enough dispute' and your only reference is an unpublished website. There is no real dispute, the gravitational community is overwhelmingly supporting GR. You're like a creationist saying "There's dispute about evolution" in a deliberately vague way to imply something which isn't true.

    If that person had a valid model, why is it on a website and not in a journal? Why not write papers? Why not provide models people with access to detailed measurements of the sun and Mercury could check? He, like you, provides no model which can be tested to see if their claims are valid. Vague "OMG, a tidal bulge explains the Ice Age!!" isn't a model, it makes no predictions which can test it, it has no precise statements. He even admits on his homepage that he prefers teaching over research and does a double amount of teaching. So his work is vague, not his primary interest and has absolutely nothing to it.

    So even your link doesn't support you, it doesn't provide anything other than "Because I say so".

    It won't be 'confirmed', it'll just not be falsified. You can't confirm a fundamental theory by experiments, you can only provide more support for it being a good model. GR has tons and tons and tons of verified predictions, LIGO is just yet another experiment to test GR. And I'm certain that if LIGO does verify another prediction of GR you'll still say "It's not yet verified, there's another experiment they are going to do in a few years". There'll always be another experiment until the theory is eventually falsified.

    You seem to have little or no grasp of even the philosophy and methodology of science, never mind the details you should have spent years learning.
     
  16. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Well here is some data on the Earth's day length getting longer:

    http://www.creation-answers.com/slowing.htm

    Even the creationist cannot dispute the facts.

    There are many self consistent records. Everything from coral that make daily "tree rings" growth ridges to where ancient ecclipses were observed. (not in the cities where the sun's shaddow would be if the Earth spin were constant but further to the East by hundreds of miles in the older cases.)

    The creationist deny many well established facts, but they are not able to deny the slowing of the Earth's spin - to many facts all give he same results (except for slight variation as ice added at the poles speeds up the earth )

    Modern clocks and stellar observations are so accurate that every few years we add a "Leap Second" to the year to acknowlegdge this slowing of the Earth's spin.
     
  17. common_sense_seeker Bicho Voador & Bicho Sugador Valued Senior Member

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    That's the most laughable post I've read in a long time. We're not disputing the fact that the earth is slowing it's rate of spin; that's just a matter of conservation of energy imo, emitted gravitons take energy away from the earth and inner core system.
     
  18. CptBork Valued Senior Member

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    Just because they say stuff like that on Star Trek doesn't mean that's how it actually works.
     
  19. Ophiolite Valued Senior Member

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    You never read your own writing then?
     
  20. common_sense_seeker Bicho Voador & Bicho Sugador Valued Senior Member

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    There's plenty of reasons why the Earth's spin is slowing down. It doesn't mean that this causes the Moon to move further away in orbit! Holy Moly. My latest reckoning is that the Moon's orbit is getting either more or less inclined, which changes the gravitational interaction between the non-baryonic innermost cores.
     
    Last edited: Oct 16, 2009
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Can one be banned for persistent inventive ignorance?
     
  22. common_sense_seeker Bicho Voador & Bicho Sugador Valued Senior Member

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    Do you admit that just because the earth's spin is slowing, doesn't necessarily imply that this is the reason for the moon's increasing orbit? The decline of the earth's spin is intuitive, the moon moving further away is not. We don't need a condescending lecture stating the fact that internal tidal forces slow down the earth's spin.
     
  23. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Of course not. I believe angular momentum is conserved. I.e. Earth is losing and moon is gaining to keep total of this dynamic system constant.

    Only by going to a higher orbit can the moon gain angular momentum. The math is quite clear, but obviously you are ignorant of it and like to postulate silly things like "non baryon cores" etc.
     

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