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Thread: Aftermath: When the Earth Stopped Spinning SCIENCE QUESTION

  1. #1 Aftermath: When the Earth Stopped Spinning SCIENCE QUESTION 
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    I have a question that doesn't have to do with global warming but this was the only place to post since I don't see "climate science" or "atmospheric science" anywhere else. I recently saw a show on NatGeo called "Aftermath: When the Earth Stopped Spinning". The idea of the show was to explore the effects of the rotation of the earth by considering exactly what would happen if the earth came to a complete stop over the course of five years. Of course, such a thing is pretty impossible unless the earth were to collide with a planetoid, in which case there would be bigger concerns, but that is beside the point. I don't think the idea was to consider this as a realistically possible catastrophe scenario. It was more of a thought experiment to illustrate just how important the rotation of the earth is to life. Although I found the show interesting, as a physics student who has studied rotational systems, there was one thing I found quite perplexing.

    According to the program, as the earth slows, not only would the oceans migrate toward the polls causing north/south regions to submerge and equatorial areas to become dry, but so much of the atmospheric oxygen would migrate north and south that the equatorial regions would lack sufficient oxygen to sustain life. This was very surprising to me and I'm not sure I understand why. It seems to me that right now there is more atmosphere (O2 & N2) piled up around the equator than the poles due to the rotation of the earth, but I can still breathe at the north pole even though the atmospheric pressure is less there. So if the earth stopped spinning and the atmospheric levels reached some equilibrium, although the partial pressure of oxygen would be less at the equator than it is today, wouldn't there still be enough for it to be breathable? And if not, please explain why not? The show didn't explain why this occurs, only that it would. I suspect that it has something to do with the uneven warming of the sun - direct rays vs. indirect rays, but I really am not versed enough in atmospheric science to offer an educated opinion.


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    Interesting questions. The ocean and atmosphere pile up at the equator due primarily to centripetal forces. I don't have a clue why the events they describe would occur though once those forces are diminished. I'll watch for an answer as well.

    Edit. It occurred to me that gravitational pull from the sun and moon would have some unique effect too. At least to deform earth and pull on the ocean and atmosphere.


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    The more I think about this topic the far more complex it becomes. First I am no longer entirely convinced that the atmospheric pressure would be different at the poles than the equator in a rotating system. This is because the atmosphere, unlike the oceans is a gas not a liquid, and gases expand to fill the available volume. As the earth rotates the drag on the atmosphere is not as substantial as it is on the oceans. Thus the oceans tend to follow the rotation more closely than the atmosphere so I'm not convinced that centripetal forces play a significant role in atmospheric pressure. That said I did a little further research on the web to see if any other forums on science had Q&A on the topic. It was interesting the contradictory answers I uncovered. One professor explained that due to the greater amount of water vapor at the equator, the partial pressure of O2 and N2 is less at the equator than the poles. But if the earth stopped and the seas migrated to the poles, that would cause the equator to be dry and one would expect the partial pressure of O2 to increase. On the other hand, the lack of water and increased heat at the equator could cause plants to die off. Should we assume that the lack of plants would cause the partial pressure of O2 to decrease? But O2 is a gas, and gases fill the available volume, they don't just stay put in one place like a liquid or a solid would. So even if more oxygen was produced near moderate latitudes by the available vegetation this oxygen would migrate throughout the atmosphere and reach equilibrium, and once again there is no reason to believe there would be less oxygen at the equator. Finally, another professor said that the total pressure of the atmosphere is less near the poles than at the equator due to the effect of temperature. Less temperature by PV=nRT means less pressure. But that drop in pressure due to temperature is because the kinetic energy of the molecules is less, so they exert less force on their surroundings. It has no effect on the amount of oxygen present, or in other words, it has no effect on the number of oxygen molecules per cubic foot of air. So I'm still at an impasse and I'm beginning to think the authors of this particular Nat Geo program may have just got it all wrong.
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    but so much of the atmospheric oxygen would migrate north and south that the equatorial regions would lack sufficient oxygen to sustain life.
    Sounds like BS to me. A giant Hadley cell would set up between the equator and the poles with perhaps a few tens of millibars gradient between them. It would be nothing like the hundreds of millibars necessary to create difficulty in breathing at the equator. Nor would the atmospherics gases separate, there's still be plenty of mixing due to convection (among other agents). In short the program is wrong.
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    This is because the atmosphere, unlike the oceans is a gas not a liquid, and gases expand to fill the available volume. As the earth rotates the drag on the atmosphere is not as substantial as it is on the oceans. Thus the oceans tend to follow the rotation more closely than the atmosphere
    If the atmosphere did not follow earth's rotation, just as closely as the ocean or anything else, the wind speeds at the equator would be spectacular.
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    Duh, of course. Can't believe I missed that. Good point!
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    Well how about that.

    I've already written a science fiction novel on this very scenario :-D

    Two actually - one based in the future and I've almost finished the prequel, based on present day.

    Very interesting to see this program and its predictions. Didn't really match mine. I didn't see the atmosphere issues or global melts coming, and think they got that wrong anyway.

    (Longlight by Robert Kimber)
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    if the entire earth were to cease its spinning, the core would also likely stop. anyone who has scene the movie "the core" or who has an understanding of electromagnetic forces knows that the earth is protected from a lot of ionized particles emitted by the sun due to a magnetic field coming from the spin at the molten iron core of the earth. so if we were to stop spinning most of the planet would be zapped. and if we weren't spinning relative to the solar system but still revolved around the sun, one day would equal one year. and one year after the effect you describe, cosmic rays will have completely wiped out all surface life on the planet.

    as an idea for your science fiction book rootball, you may wish to write it about the micro organisms surviving at the depths of the ocean, for they will be the only things that i know of that would survive all of this.
    physics: accurate, objective, boring
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    Quote Originally Posted by saul
    if the entire earth were to cease its spinning, the core would also likely stop. anyone ....... knows that the earth is protected from a lot of ionized particles emitted by the sun due to a magnetic field coming from the spin at the molten iron core of the earth.
    this is incorrect. The field arises from convective circulation in the outer core. There is no reason that the elimination of spinning would terminate the convection, so the magnetic field would remain in place.
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    Quote Originally Posted by Ophiolite
    this is incorrect. The field arises from convective circulation in the outer core. There is no reason that the elimination of spinning would terminate the convection, so the magnetic field would remain in place.
    Kinda works for my characters

    Re human survival, I worked on the premise that people could either hibernate during the dark cycle or travel eternally in the light.

    Both approaches have their problems of course.

    The other issue I came upon was temporal measurement.
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    Quote Originally Posted by saul
    anyone who has scene the movie "the core"
    ....

    Are you serious??
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    they add a lot of theatrics, but the physics behind it is real. so the short answer is yes.
    physics: accurate, objective, boring
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    biology: accurate if chemistry is accurate, somewhat subjective, fascinating
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    Quote Originally Posted by saul
    they add a lot of theatrics, but the physics behind it is real. so the short answer is yes.
    OK, you are joking.
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    Quote Originally Posted by saul
    they add a lot of theatrics, but the physics behind it is real. so the short answer is yes.
    Which physics was that? It was pure nonsense form start to finish. About the only fact that was correct is that the interior of the Earth is hot.
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    Right, so I joined this site just to answer this question, because I'm obssesive like that. So-
    You forgot to take into account the effect that the earth's rotation has on the land itself. The earth is not a perfect sphere-rather, the equator is a couple dozen miles further from the center of the earth than the poles. It is only due to the earth's rotation that the atmosphere and hydrosphere blanket the crust at a consistent depth. Without it, the fluids would collect in the shallower poles. The land would eventually follow suit, but it would take much longer.
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    This is somehow getting a bit off topic, I apologise for that. But concerning the Core, look at the right hand side of this page: http://www.intuitor.com/moviephysics/

    I quote:
    Intuitor's Pick - #1 Insultingly Stupid Movie Physics Classic

    This movie is so bad we finally had to force ourselves to quit writing and post the review.

    [XP] The Core (2003)

    recommended- It's so bad, it's good.
    It's the worst physics movie...ever....
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    The Core (2003) - Intuitor's Pick - #1 Insultingly Stupid Movie Physics Classic - It's the worst physics movie...ever....
    Yip, terrible. Started good and went south really fast!
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    Quote Originally Posted by KALSTER
    The Core (2003) - Intuitor's Pick - #1 Insultingly Stupid Movie Physics Classic - It's the worst physics movie...ever....
    Yip, terrible. Started good and went south really fast!
    If it had gone south it would have come out in Antarctica rather than reaching the centre of the Earth. :wink:
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    Guys.. i think this was a very interesting scenario... we've still not gotten any sensible answer.. apart from a couple of folks... i think the mere thought of such a scenario is chilling and exciting... i really wonder what will happen.. but one thing is for sure.. its not a simple answer...cus there are so many forces playing their parts.. like centipetal, centrifugal, atmoseheric, magnetic, solar, gravitational from sun, moon etc etc that it would be really hard to predict anything (my guess)...!
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    Quote Originally Posted by replay1981 View Post
    According to the program, as the earth slows, not only would the oceans migrate toward the polls causing north/south regions to submerge and equatorial areas to become dry, but so much of the atmospheric oxygen would migrate north and south that the equatorial regions would lack sufficient oxygen to sustain life. This was very surprising to me and I'm not sure I understand why. It seems to me that right now there is more atmosphere (O2 & N2) piled up around the equator than the poles due to the rotation of the earth, but I can still breathe at the north pole even though the atmospheric pressure is less there...
    I've watched the show and I think it never said that, I think you're just projecting your view on what you hear. It is a long show and you may have been tired and start making stuff up as you hear it. The show tell us about changes in climate and its effect on individuals in a progression from day 1 to 5 years later: where earth gradually stop, and show where human survivor may end up with at each step...
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