Could the earth stop spinning one day??

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Vega, Jul 14, 2006.

  1. invert_nexus Ze do caixao Valued Senior Member

    Messages:
    9,686
    Hmm.
    Better or worse?
    You need context to judge.

    I'd say that in this case, you provoked him.
    And you did it in a way you've done several other times.
    People say things that you don't like and instead of responding to them, you focus on a few negative aspects of their post and basically start jibing them. You did it to me. You did it to Superliminal in here. (Although, I'll admit that I was a lot more... provoking than Superliminal began.)

    Superliminal was trying to discuss this with you. But, you got pissed off and stomped off. Started going off on rants about 'scientists' and blah blah.

    You lost the ball.


    Hey. I think you're actually an ok guy underneath it all somewhere. You just have some serious shit affecting your perceptions.
     
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  3. MetaKron Registered Senior Member

    Messages:
    5,502
    I believe that an intelligent and reasonable person may speculate on some plausible mechanisms. Try to understand the idea that there are things that we don't know, even about just plain gravitational theory, until we have advanced enough modeling techniques to test it conclusively. Even if we really knew the physical properties of the Earth's interior to any degree of certainty, we would have to use a hell of a lot of CPU time to exhaust the possibilities. I am tired of being called a dummy because I see possibilities, and I think that those who do that are without integrity.

    "We can't prove one way or the other" is the best we can do and I won't believe anyone who insists that we can. I can't predict what a proper computer model of a thing like a close approach will show. No one else can either. If they could they wouldn't need the computer, would they?

    I think I've touched Superluminal's little exposed nerve of the knowledge of his own lack of competence. Too bad that this offends him. Some people might take that as a challenge, as a place to improve themselves a little.

    It is a reasonable speculation that a close approach by a given mass can cause unpredictable effects including stopping its rotation for a period of time. Knowing that the approach and the exit of that mass will be roughly symmetrical relative to the Earth, it is plausible that such effects will be reversed to some extent, leaving the rotation at roughly the same period that it had before but not necessarily around the same axis.

    The plausibility of such effects cannot be confirmed or denied without either a way to see what actually happened or a reliable way to model it. People offer rebuttals accompanied by a lot of shouting, waving of arms, and even insults and intimidation, but they don't offer much if anything in the way of analysis. Then they expect me to believe them. I can't believe them. What I believe is that they protest too much.
     
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  5. MetaKron Registered Senior Member

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    5,502
    How do you know that there is no evidence?
     
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  7. MetaKron Registered Senior Member

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    5,502
    We all do, and we still have to work with what we've got. If you think I'm fucked up, you should have seen what I was raised by.

    Some people start in with this "no evidence and you're an idiot" stuff and I just can't believe that they have anything to contribute. If they do, how do they show it?
     
  8. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    15,162
    That's fine. But you cannot claim the earth did in fact stop spinning for one day...
     
  9. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    15,162
    Oh! So you have evidence? Let's see then!
     
  10. MetaKron Registered Senior Member

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    5,502
    I can claim that several ancient cultures saw something like that happening. It is not right to claim that they didn't just because we can't figure out how it happened. The evidence is there. It does exist. Its veracity and reliability may be questionable, but I think that there is a pretty good chance that the observed events did happen.
     
  11. imaplanck. Banned Banned

    Messages:
    2,237
    Just like fuzzy pictures and word of mouth is good evidence for UFO nut's to conclude theres a good chance aliens are here.
    If you call that which you have just posted 'evidence' it's no wonder you have a problem with science.
     
    Last edited: Jul 21, 2006
  12. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

    Messages:
    15,162
    As I said before, let's see the evidence!
     
  13. Laika Space Bitch Registered Senior Member

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    638
    No, the mantle is solid rock. At no point (not even the Moho) is the mantle fluid enough to allow whole crustal slippage. Even if the Moho was a layer of God's own lubricant, the mantle is 'intruded' by the roots of the continents and by subducting plates, which can penetrate for hundreds of kilometres, so it could not be displaced in its entirety.
     
  14. superluminal . Registered Senior Member

    Messages:
    10,717
    In case anyone's interested, the energy we're talking about (that would have to be applied to the earth over less than one day to stop it) goes like this:

    Rotational kinetic energy of the earth: E<sub>r</sub> = 1/2 I &omega;<sup>2</sup> is roughly 10<sup>29</sup> J.

    The energy of one Hiroshima type atomic bomb is roughly 10<sup>14</sup> J.

    If you divide it out, it comes to the energy of about 10<sup>15</sup> atom bombs.

    To make that more visualizable, the total surface area of the earth is 510,065,600 square km.

    If you divide that out you get 19,605,321 atomic bombs detonated on every square kilometer of the earth, over less than one day.

    If this does not impress the magnitude of the energy required (for those that believe in energy that is) then you are all much harder to impress than me.

    Thanks for your time.
     
  15. MetaKron Registered Senior Member

    Messages:
    5,502
    This way at least we have some kind of answer to just one of the questions involved. We are starting to actually think about whether there is a mechanism instead of relying on kneejerk reactions.
     
  16. MetaKron Registered Senior Member

    Messages:
    5,502
    I hope that you're not trying to push a "flash of light" hypothesis. So there is this much momentum to try to transfer or cancel out or do something with. That will be expressed in the acceleration of the bodies involved.

    The Earth rotates roughly 1,000 miles per hour at the equator. A body that makes a close approach will accelerate by about 25,000 miles per hour if it gets close enough. Pound for pound that's 625 times the energy of an object moving 1,000 mph, and a lot of the Earth's mass isn't moving at that speed. The momentum is there to be transfered. If an approaching body exerts about a tenth of a gee against the 1000 mph of the equator, it would only take about 20 minutes or so to stop it, and it might restart that rotation when it left. This is where you need some real heavy duty modeling.
     
  17. MetaKron Registered Senior Member

    Messages:
    5,502

    The trouble is that this "serious shit" is real. I am living a very poor illusion of a life right now, with diminished potential and with a lot of forces that will destroy whatever I do if I seem to be accomplishing what I want to accomplish. A lot of people are trying to take away my rights and my life. They constantly degrade my environment and that will not improve. They will just find another degradation to use while pretending that it somehow makes the human race safer. What do you expect? They don't profit from freedom. They also don't profit from actually solving problems.
     
  18. superluminal . Registered Senior Member

    Messages:
    10,717
    With all due respect, you dont need heavy duty modelling to solve this "problem".

    1) I don't know what a "flash of light" hypothesis is. The energy analysis is meant to illucidate the magnitude of the energies involved.

    2) Momentum transfer between close approaching bodies has no effect on the rotation of those bodies (except as a miniscule amount of tidal drag for the short duration of the encounter as described in a previous post). The orbits can be drastically affected (as I pointed out before). This is where momentum transfer comes into play.

    As a side note, this is one way spacecraft using a "gravity assist" take advantage of this fact. They "steal" a microscopic amount of the orbital momentum (not rotational) from the planet by executing a precision flyby maneuver. Here are a couple links:

    http://www.mathpages.com/home/kmath114.htm

    http://saturn.jpl.nasa.gov/mission/gravity-assist-primer.cfm

    3) Newtonian physics does not work at all in the way your post indicates.

    Seriously, MetaKron. It seems like you have the smarts, interest in, and love of, cool natural phenomena. I have no idea what your educational background is or your personal situation but there are some excellent physics books out there that can give you a great physics foundation. Also, there are tons of free web resources that are excellent.

    SL
     
  19. MetaKron Registered Senior Member

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    5,502
    Superluminal, I know that what may seem straightforward in math can get into some really crazy complications when you try to apply it to a problem like this. You can't close that door without doing the math. Even after doing the math there is the possibility of making a large mistake without knowing it. I know of one that I am going to exploit eventually to write a book, and no I am not going to hint at what it is, but it is a good one.

    Yes, Newtonian physics works something like the way that my post indicates. How would a close approach change a body's rotation? The kind of hint I am looking for is in the tidal bulge that is induced when that body approaches. That is only a hint. It's enough to keep the door open for. Then does the approach of and the recession of that body transfer momentum a particular way? Does the combination of all the pulls leave us with a roughtly similar rotation but on a different axis? It would take some good number crunching to even start to produce a model that has the slightest chance of being accurate.

    About all I can do for the moment, as in within the next few hours, is compare things like the effects smaller masses on close approaches. Two hundred fifty miles up is a thousand times closer than the distance to the moon (roughly) so, pound for pound, a mass has a million times the effect on the Earth's surface at that distance. Now we're talking about chunks about twenty miles in diameter having the same tidal effect on a limited area of the Earth.

    We also need go get into what happens when a planet-sized object gets close enough that it and the Earth have a common center of gravity.

    I don't think that we can evaluate the effect on rotation without knowing the plasticity of the Earth's different layers. I can't know if the Mohovoric Discontinuity allows slippage or if it contains a fluid of some kind. Maybe it's created by the tidal effects of the Moon. How the hell would I know? I see an unknown, don't know how anyone factors it into the model, and I see a possibility that I can't and won't lock out. I can't see how it could be anything but a fluid, liquid type, because fluids tend to occupy a certain level, like sea level.

    No matter how much I learn about physics, there will be no way for me to predict such things without accurate models. I can't even predict an orbit without an accurate model, no one can, and our models are often oversimplified. Tidal effects do affect the rotation of the planet on its axis and the period and shape of the orbit. Models that don't take these into account won't predict anything but a steadily precessing ellipse and a perfectly constant "day."
     
  20. superluminal . Registered Senior Member

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    10,717
    Well MetaKron, good luck with your research.
     
  21. MetaKron Registered Senior Member

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    5,502
    Thank you. I don't know what I might come up with, and that's the point.
     
  22. Laika Space Bitch Registered Senior Member

    Messages:
    638
    MetaKron, I would suggest you give up looking to the Moho for your slippage surface. The Moho marks the compositional boundary between the relatively felsic crust and the ultramafic mantle, but it does not necessarily represent a behavioural boundary, as the crust is underplated by a thickness of upper mantle that varies depending on the tectonic environment. Together, the crust and the rigid upper mantle make up the lithosphere. The depth of the aesthenosphere below varies from a few kilometres to up to a hundred or more. The aesthenosphere locally contains up to five per cent melt, but certainly does not lie at a certain level, like sea level. Hot-spot traces and huge slabs of subducting lithosphere show that the lithosphere is not prone to sudden dislocation en masse.
     
  23. MetaKron Registered Senior Member

    Messages:
    5,502
    I'm not going to stop looking at it until someone knows what it is for certain and tells me, depending on what they say of course. "Not necessarily" doesn't close any doors. I am also not sure whether the theory requires surface slippage. That's just one option.

    Most likely the theory would depend on the tidal bulge. If the Earth and the approaching objects produced a sort of tidal lock temporarily, then it could have slowed down over a long enough period of time that no one would feel significant deceleration. I only have a vague hand-waving explanation for how the rotation can then be restored to anything at all like the original, but that's enough for a plausible mechanism. Proving it impossible is difficult. And yes, if someone looks it up, there is an interaction between the rotation of a planet around its axis and a satellite or a passing object. It is subtle but it is there.
     

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