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Re: Warm- vs. Cold-blooded Dinos



>
>I am not suggesting anything about the pole behavior of the earth, but a
>non-symmetric rigid body spinning about its intermediate inertia tensor will
>spin stablely for a period inversely related to the initial deviation of the
>intermediate intertia tensor from the spin axis.

Obvious really, I'm glad you cleared that up for me.

>
>Try this: take an expendable book and wrap it with a rubber band to keep it
>closed.  Hold the book so that the title faces you and throw the book up in
>the air so that it spins top over bottom.  No matter how hard you try, you
>will not be able to spin the book stablely for any length of time.  The book
>might spin stablely for a moment or two but it will suffer a "pole flip."  If
>the spinning book is completely isolated, no energy is being lost or added to
>it and that is my point.

I may well have missed the point here, but are books held together with
rubberbands adequate models of a rotating earth with a molten center and
crusty layer on the outside? What about gravity (completely different
between your analogy and the real earth).

OK, lets start a-fresh. Imagine a rotating jam-donut, 95% jam and 5% donut
crust. Now I am not sure about all the technobabble that makes this
correct, but as I see it, providing the donut is rotating on a stable axis,
no problem. But begin to change that axis of rotation and the rotating jam
will be have differently to the rotating donut crust (liquid v solid). If
this difference in movement is great enough, the friction between the donut
crust and the jam could be considerable. If, instead of a jam donut we have
an earth with a molten core, the friction generated between crust and
mantle when the axis changes would be enormous, ... wouldn't it? And one
way that friction could be disapated could be as heat across the crust, ...
couldn't it?

Anyway, I am just a very dead croc person, physics was never my strong point.

Why did the chicken cross the mobius strip? To get to the other ......

Cheers, Paul

pwillis@ozemail.com.au

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