Hi John, Gordon, Malcolm et. al. Gordon is basically right saying that if not for friction the rotation would stop at infinity and the decay of rotation would be exponential. Yet even small amount of friction dissipates energy and the longer it works the more its effect is visible and we are talking millenial (at least) time scale.
Reliable predcition when stopping would occurr is impossible. Extrapolation would go too far, we do not even know initial conditions accurately enough, not to mention the equations. Relatively "simplier" problems like that of the stability of the Solar System (whether planets would go away or stay or fall onto the Sun) cannot yet be solved for more than probably hundred thousand years (professional astronomers engaged in sky mechanics would know exactly the current state of the art). Stirred water in the jar would stay whirling for ever if not for viscosity. On the other hand without viscosity we would not swim and planes would not fly. Still on the other hand if viscosity were much bigger, say like that of tar, we would not swim either. So this is good that curls in water stop at the rate they do and maybe this is not that bad that the Earth slows down. I agree wtih Malcom that side threads on the list are very interesting so we should thank our moderator in Koeln for tolerance. Slawek At 08:53 AM 2/28/99 -0800, Gordon wrote: >John, > >The earth will not stop completely, at least due to tidal friction. Ignoring >nonlinear effects, the tides cause an "exponential decay" in rotation rate, a >given fraction every year. The water in an initially-stirred jar of water >never stops either (in theory) for the same reasons. > >I yield to others for answers to your other interesting questions. > >Gordon > >At 06:56 AM 2/28/99 , Phil Pappas wrote: >>Hi guys, >> >>If the earth's rotation is slowing, due to lunar tidal drag, then in what >>year will it stop completely? > > >Gordon Uber [EMAIL PROTECTED] >Reynen & Uber Web Design http://www.ubr.com/rey&ubr/ >Webmaster: Clocks and Time http://www.ubr.com/clocks/ > > Slawek Grzechnik 32 57.4'N 117 08.8'W http://home.san.rr.com/slawek
