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    Re: Tycho Brahe Mars oppositions
    From: Fred Hebard
    Date: 2004 Dec 4, 02:12 -0500

    On Dec 4, 2004, at 12:38 AM, Frank Reed wrote:
    
    >
    > Fred H wrote:
    > "However, the ice ages would have had a profound, global effect on
    > tidal
    > modulation of the earth's angular momentum.  The end of the last ice
    > age was rather sudden, but the onset depended on accumulation of snow
    > over extended periods, and would have been longer, I expect: imagine
    > building a mile thick sheet of ice at the rate of 20 inches per year."
    >
    > The global tide pattern would have been roughly the same even with sea
    > level so much lower. The tidal friction would have been lower since
    > the shallows over the continental shelves would not have existed. How
    > much, I don't know...
    >
    > The geophysicists who worry about these matters talk about changes in
    > tidal braking occurring over the very-long geological time scale and
    > that the changes arise from re-arrangements of the continents and
    > ocean basins themselves.
    >
    
    My intuition, which can be dead wrong in physics, is that 10% less
    water sloshing around in a cup would move the cup less.  Additionally,
    would not concentration of that water in the north be similar to an ice
    skater pulling in her arms to spin faster?  I guess the weight of the
    ice relative to the mass of the earth would be important here.
    
    I'm sure changes in the ocean basins due to continental drift could
    have profound effects, but might not the ice age change the odd second
    of delta-T now and again?
    
    Fred
    
    
    

       
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