On Wed, Jul 27, 2016 at 8:08 AM, Attila Kinali <att...@kinali.ch> wrote:
"I am not sure you can apply this definition of Q onto earth." It doesn't make sense to me either. If you mark a point on the surface of a sphere then you can observe that point as the sphere rotates and count rotations to make a clock. If you think of just a circle, then a point on it viewed in a rectilinear coordinate system executes simple harmonic motion so the motion of that point looks like an oscillator, so that much is OK. But unlike the LCR circuit, the pendulum and quartz crystal, the sphere's rotational motion does not have a resonant frequency. Another way of characterizing the Q of an oscillator, the relative width of the resonance, makes no sense in this context. It seems to me that the model of the earth as an oscillator is misapplied and that the 'Q' is not a meaningful number. I think the confusion arises here because of a conflation of a rotation of the sphere (which marks out a time interval) with an oscillation. Both can be used to define an energy lost per unit time but the former doesn't have anything to do with the properties of an oscillator. Something else that indicates that the model is suspect is that the apparently high 'Q' implies a stability which the earth does not have, as Tom observes. Viewed another way, this suggests that the model is inappropriate because it leads to an incorrect conclusion. Time for bed. I'll probably lie awake thinking about this now :-) Cheers Michael On Wed, Jul 27, 2016 at 8:08 AM, Attila Kinali <att...@kinali.ch> wrote: > Hoi Tom, > > On Tue, 26 Jul 2016 12:36:37 -0700 > "Tom Van Baak" <t...@leapsecond.com> wrote: > >> Among other things, the quality-factor, or Q is a measure of how slowly a >> free-running oscillator runs down. There are lots of examples of periodic or >> damped oscillatory motion that have Q -- RC or LC circuit, tuning fork, >> pendulum, vibrating quartz; yes, even a rotating planet in space. > > I am not sure you can apply this definition of Q onto earth. Q is defined > for harmonic oscillators (or oscillators that can be approximated by an > harmonic oscillator) but the earth isn't oscillating, it's rotating. > While, for time keeping purposes, similar in nature, the physical > description of both are different. > > Attila Kinali > > -- > Malek's Law: > Any simple idea will be worded in the most complicated way. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.