Could the earth stop spinning one day??

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

  1. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    So... what;s the point of knwoing whether the panet once stoped for a single day?

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  3. MetaKron Registered Senior Member

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    Taking that question seriously, what is the point of knowing whether a very deadly hazard to life on Earth occurs every few thousand years? What is the point of possibly being able to pinpoint the next time that it will happen and then providing for that eventuality?
     
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  5. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    How's that deadly? Even asteroids happen with incredible greater frequency. So why should we bother?
     
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  7. MetaKron Registered Senior Member

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    We should bother because we have a global civilization and it will be knocked back to the Stone Age again if this happens again. This is also a question that has answers that will eventually be very useful to us.

    Also, there are major religions who are hooked on the theory that all those disasters were caused by a magical being over two miles tall with a long white beard. Now, really. This is the 21st century. We understand about natural disasters caused by the close approach of massive objects, impacts with massive objects, and volcanoes, and the idea that God is going to smite us still has a stranglehold. Knowing for a fact that the basis of these religions was a set of natural disasters caused by something that we can name will go a long way towards knocking the pins out from under these manmade disasters that we laughingly call religions. Some of these people have been enforcing ignorance and illiteracy for almost 2,000 years. They have made my life and the lives of a lot of others a miserable sort of Hell. And these days the only way that they can stay in power is to place controls on science, pretending to be ethicists.
     
  8. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    So... you need an asteroid to supposedly make the planet stop spinning. The chances of the earth being hit by an asteroid is more then 1 in 1 million. So the chances of an asteroid the right size to go by in the right way to make the earth stop spinning if that is even possible in any way is way WAY smaller then the planet getting hit by an asteroid- something like 1 in 1 zillion. So... you rather spend your time and effort investigating something that has a probability of happening of 1 in 1 zillion then one that has the probability of 1 in 1 million? No wait! Not 1 in 1 zillion, because you claim it has happened before! So you have to square that zillion!

    Gosh! I should be a defense lawyer! LOL!

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  9. MetaKron Registered Senior Member

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    Close approaches are far more probable than direct hits. The Earth has a cross-section of 8,000 miles. Close approaches depending on how you define close can be within an area hundreds of times larger, thus increasing the probability hundreds of times.
     
  10. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    The probability of a close approach is actually very small. The exact configuration you are suggesting is even smaller.
     
  11. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    You believe in Planet X, don't you?
     
  12. Vega Banned Banned

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    It's existance is mere speculation and it hasn't been sighted yet!!!
    Although unconfirmed reports suggest that a telescope is been built in antartica this year for the purpose of scanning the southern region of space for planet X.
     
  13. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    Anyways... I bet this is the purpose of the thread...

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  14. MetaKron Registered Senior Member

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    I am keeping an open mind about Planet X.
     
  15. eburacum45 Valued Senior Member

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    Superluminal's calculation of the energy involved is important; if you apply that much energy to the Earth you will damage it by that amount. Not necessarily in a flash of light; more likely in a flash flood, tsunami and landslide.
    You realise that accelerating the crust of the earth by even one tenth of a gee would be equivalent to tilting the entire surface of the earth at an angle of about six degrees. All the oceans would flow downhill, as would any solid object not nailed down. The surface of the Earth would become a superrotating slurry of mud,
    Needless to say this has not happened. I have, for my sins, studied geology at college; such a flow could cover the ocean beds in turbidites; they are not there.
     
  16. superluminal . Registered Senior Member

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    10,717
    I think even more importantly, there is this:

    Imagine a basketball rotating, for arguments sake, in microgravity aboard the ISS. How would you stop its rotation? First, you need a way to convert its energy of rotation to some other form or transfer it. I know of only two ways to stop the axial rotation of an object.

    1) Grab it from a non-rotating external platform. This will convert all of the rotational energy to heat (via friction). This is the same as tidal drag as was discussed earlier. So, here's another calculation:

    The earths volume is roughly 1.1×10<sup>12</sup>km<sup>3</sup>

    If you distribute our 10<sup>15</sup> atom bombs throughout that volume you get about 9000 atom bombs for every cubic kilometer. If we assume the "stoppage time" to be 6 hours we get 1500 detonations per hour.

    Thats 1.5x10<sup>18</sup> J / hour. I suspect that would be enough to render the entire volume of the earth molten, and if applied only to the surface layers, enough to turn it into a million degree gas. As a geologist eburacum45 you might be able to confirm this.

    2) Transfer the rotational energy to another body such as the gyro's on a spacecraft (or like the flywheels in some kinds of hybrid cars). Of course, the "gyro" must be on the body, and must have the mass x angular momentum capability equal to the body you are trying to stop. And of course you need a mechanism to couple the two bodies which requires energy. Again, see the "atom bombs" calculation.

    Remember that the conservation of energy (any form of energy) is one of the most fundamental laws of the universe.
     
    Last edited: Jul 23, 2006
  17. Laika Space Bitch Registered Senior Member

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    Well I'm telling you now (though I don't expect you to accept my opinion as definitive). While humans have been humans, the surface of the Earth has not moved as a unit independently of the mantle. Chains of extinct volcanoes show that tectonic plates have moved relatively steadily over mantle plumes for millions of years. Seismic tomography and earthquake first motion studies show huge sinking slabs of lithosphere, hundreds of kilometres deep in the mantle, which correlate perfectly with the surface expressions of subduction. When I said that "the Moho marks the compositional boundary between the relatively felsic crust and the ultramafic mantle, but it does not necessarily represent a behavioural boundary," I meant that in some places it does, but in most places it does not. I did not mean to imply that the crust-mantle compositional boundary might constitute a detatchment plane. It does not. Either the whole Earth paused in its rotation, or no part of it did (save for the oceans, perhaps). Please consider this in addition to the cogent reasoning provided by Superluminal and Eburacum45.
     
  18. MetaKron Registered Senior Member

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    5,502
    Superluminal, the weight of the Earth is officially 5.9742 * 10^24 kilograms. I would feel pretty safe pumping 1.5 * 10^18 joules per hour into a thousandth of that mass. You're talking a fourth of a millionth of a joule per hour for every kilogram of the Earth's mass, or a fourth of a thousandth of a joule per hour for a thousandth of that mass. A joule is .239 of a calorie. That would heat a kilogram of water by .000239 of a degree. A thousandth of that is .000000239. I believe that we are quite safe there.
    Edges of masses slipping by each other are another problem. Wherever there are fault lines, expect trouble.

    See what I mean when I say that the notion becomes more credible when you think it through and do the math.

    You're talking about a millionth of a joule per kilogram per hour and I have to spend several joules of energy, at a low heat effiency, per kilogram per minute to stand upright.

    The tidal bulge theory is a better theory than the mantle slippage theory even if we don't know what the Discontinuity is.
     
  19. Laika Space Bitch Registered Senior Member

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    638
    How big a tidal bulge are you talking, and where do you suppose the geological evidence is hiding?
     
  20. superluminal . Registered Senior Member

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    You don't seem to understand. I can think, and I can do math. You have to stop the WHOLE earth and under those circumstances you must "dispose of" the amount of energy I've calculated.

    Laika has explained in detail that the eatrhs outer layers cannot slip around on the underlying ones like two nested toy tops. There is geological and seismic evidence to support this.

    Any theory you propose must, at least, come to grips with these facts.
     
  21. MetaKron Registered Senior Member

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    5,502
    In one estimate you say that I need to dispose to 10^29 joules, and in another you say 10^18 joules per hour. The Earth weights about 6 * 10^24 kilograms, and simple division tells me that we have about 1.66 joules per gram of Earth to deal with if we use the larger figure. We're looking at temperature increases in the single digits, being that a joule is .239 of a calorie. This is even leaving out the transfer of momentum to the intruding object.
     
  22. superluminal . Registered Senior Member

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    10,717
    Ahh. I see the disconnect. Reread my post.

    That's per cubic kilometer. Sorry, it was a bit ambiguous the way I wrote it.
     
    Last edited: Jul 24, 2006
  23. superluminal . Registered Senior Member

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    10,717
    No matter how you cut it, there's a tremendous amount of energy to be reconciled if one is to stop the eatrh. Even if you look only at the surface layers (which dosen't happen, QED) you would have to consider the heat build up at the interface between the moving and non-moving spherical shells. Tremendous energy. No doubt about it.
     

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