[time-nuts] Q/noise of Earth as an oscillator

David davidwhess at gmail.com
Tue Jul 26 18:14:16 EDT 2016


On Wed, 27 Jul 2016 00:08:47 +0200, you wrote:

>Hoi Tom,
>
>On Tue, 26 Jul 2016 12:36:37 -0700
>"Tom Van Baak" <tvb at 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

It seems reasonable to me.  The calculation returns a dimensionless
number which does represent the run-down time.  Any reference duration
like hours, months, or years would have returned the same result.


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