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    Re: Navigation News article on leap seconds.
    From: Frank Reed CT
    Date: 2005 Oct 10, 17:41 EDT

    Jared, you wrote:
    "And that's the point. The earth's spin rate CAN be changed, and there  are
    environmentalists suggesting that we're already changing it or bordering  on
    changing it."
    
    We have changed it. No doubt about it. But the change  is miniscule. Huge
    reservoirs created in mid-northern latitudes especially have  moved a significant
    amount of mass closer to the Earth's axis of rotation  (poleward). But this
    change in rotation rate is almost certainly unmeasurable  and in any case would
    be masked by much larger natural changes. The big loop  current in the Gulf
    of Mexico this summer (the one responsible for "cooking"  Katrina and Rita into
    super-storms) piles up more water in one place than most  any of those
    reservoirs. Here's a GIF of the beast from the end of  August:
    http://www7320.nrlssc.navy.mil/global_nlom32/navo/GOM1UV/TOPEX+ERS2+GFO+MOD_SS
    HUV_GOM1UV_20050831.001.gif
    This  map is showing sea surface height. It's over half a meter higher than
    the rest  of the Gulf at the center of that swirling eddy. By the way, the
    above URL  should be all one line. I expect it will be split up in transit.
    
    And:
    "So, let the billion chinese sneeze instead of throwing rocks. OK?  Plain
    thrust
    vector, a billion weak rocket engines."
    
    That still won't  work. The air "catches" the sneeze and rather quickly
    transfers that momentum  back to the Earth. Unless they sneeze above escape
    velocity.
    
    And:
    "The point being, a sufficiently motivated civilization could easily change
    or
    standardize the spin rate of their planet, if they had any desire to do  so."
    
    Yes. I agree. It's merely a matter of money. But I suspect any civilization
    with sufficient wealth to micro-manage their planet's rate of rotation  will
    find better ways to spend their time! 
    
    -FER
    42.0N  87.7W, or 41.4N 72.1W.
    www.HistoricalAtlas.com/lunars
    
    
    

       
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