The earth's rotation rate is slowing down because of friction against the tidal bulges caused by the gravitation of the moon (major factor) and the sun (lesser factor). The earth's rotational energy is dissipated as heat, but where is the angular momentum going, and what physical mechanism brings that momentum there?
(In reply to
re(3): I disagree - me too, with you by ThoughtProvoker)
Let me get this straight, Thought, (since I'm so confused). Are you saying the earth's rotatational velocity would remain constant over the millenia if it had no moon?
Regarding the raw egg: Attach the raw egg to a motor and spin it for as long as you like (to get rid of the "one quick twist" argument), and then release it. In fact set up the system so that both the raw egg and hard-boiled egg are spinning on motors, side by side until both have achieved the same angular momentup. Then release both. I predict that the raw egg will come to a stop much more quickly. Before you continue your argument, you really need to explain that (or disprove it empirically).
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Now having said all that, I'm going to concede the argument in part, based on reading that I've done about actual measurements. I have to admit that I'm surprised by the slow-down effect that the moon has on the earth's rotation, based on these measurements--it does indeed appear to be the major contributor to the overall slow down.
So, I'm withdrawing my initial disagreement with the solution to this puzzle.
However, I still maintain that the earth would still slow down if it had no moon (or other nearby orbiting objects to transfer its angular momentum to). Here's a quote from a study I was reading about regarding the rotational slow down of the sun and Jupiter (http://mb-soft.com/public/planetro.html):
"The fact that long-term frictional losses of kinetic energy would almost certainly occur represents an entropy situation. It is presented that Jupiter or the Sun had earlier rotated more rapidly, and that frictional effects in their gases/atmosphere have converted some of that kinetic energy of rotation into heat. A consequence of that would be that less rotational angular momentum as well. This would result in a loss of angular momentum over those billions of years. This is not a violation of the conservation of angular momentum because of the frictional energy losses."
Much larger bodies, and much more time for the slow-down to occur ("billions of years"), but the fact is, the slow-down mechanism I described (frictional effects converting kinetic energy into heat resulting in a loss of angular momentum) certainly appears to be plausible.
Edited on September 27, 2004, 11:34 pm
Edited on September 27, 2004, 11:35 pm
re(4): I disagree - me too, with you
