Hi Jinx,

That would probably produce an interesting kind of precession, but
"levitation", in the sense of being able to hold something up against
gravity without applying an external force to it, is definitely not
possible (under our current understanding of physics). In essence, it
doesn't matter whether something is spinning or what it's doing, F=MA still
applies, and if gravity is pulling downward, you have to be pushing upward
(from the outside, that is, the thing cannot be putting a force on itself)
to prevent its center of mass from accelerating downward.

He may be describing what happens when you support an object AT ONE END.
You can get an effect which LOOKS like levitation if you take a spinning
object which is at the end of a stick and just support the end of the
stick. The stick can be made to stay horizontal (even though  you aren't
supporting the other end), but this isn't really levitation, because you
are supplying a force equal to the weight of the whole thing at the end you
are holding up.

This demo is often done with a bicycle wheel at the end of a perhaps 0.5
meter stick with a handle connected to it via a universal joint. You hold
the thing by the handle and without the wheel spinning, it just flops down
(so the wheel is parallel to the ground). However, if you bring the wheel
back up to vertical and spin it, then let go, it goes in circles around the
handle, SLOWLY coming down perhaps a few degrees per revolution around the
handle. (This is hard to describe without a picture, but you may have seen it).

Sean


At 12:55 PM 12/5/01 +1300, you wrote:
>In fact, I heard a man on the talkback this morning who expanded
>on simple gyros. You start with a gyro spun at high speed. The
>container that the gyro is in is spun at high speed at 90 degrees
>to the rotation of the inner gyro. Then the whole is spun at 90 degrees
>to that (ie spinning in the X Y and Z axes), all in a vacuum to reduce
>friction and power input. His claim (he says is backed and supported
>by engineers world-wide) is that the end effect is levitation
>
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