My elementary geophysics tells me that the the earth is very, very,
nearly
>a perfect sphere. The much talked about equatorial bulges or "oblate
>spheroid" shape is extremely small compared with the size of the earth.
>
>Then, my elementary physics tells me that a perfect spinning sphere has
>*NO* gyroscopic stability. Nada, none at all. If the earth were a
perfect
>sphere, after a few years a gang of fleas all farting in the same
direction
>could tilt the earth off its axis. Of course it's not quite a perfect
>sphere. So how does that tiny equatorial bulge stack up against the ice
>packs anyway? Is much of that equatorial bulge made up of seawater? I'd
>really be interested in a good explanation of the physics of the
stability
>of a spinning *elastic* sphere (perhaps fluid filled, like a
near-spherical
>water balloon for instance). I'd think its centrifugal bulge would
>contribute to stability as expected, but is it truly the same as a
rigid
>solid having a fixed equatorial bulge? How would such a fluid system
react,
>for instance, to a field which applied force to all the elements
(molecules
>or whatever) of the system all at once? The earth, even the solid rock,
>might as well be considered a near-fluid when taken altogether as a
planet.
look up in the sky, at night, an find the great stabilizer... the moon!
Greetings
Mario