[time-nuts] Japan Quake May Have Shortened Earth Days, Moved Axis

[Hal Murray]

tvb at leapsecond.com said:
> No. Look at the adev of the earth (earlier posting). The length of earth day
> varies in the *milli*second range, day to day. VLBI measurements are under
> 0.1 millisecond, which comes to about 1e-9 resolution.

> Realize that none of the NASA "earthquake may have shortened" press releases
> are about real measurements of rotation. They are just impressive models of
> changes in momentum. The predictions are in the *micro*second range. The
> press does not always distinguish between milli and micro. 

Ouch.  Thanks for the correction/heads-up.

[Here is the graph:
  http://www.leapsecond.com/museum/earth/1sigma1.gif
and background
  http://www.leapsecond.com/museum/earth/ ]


Do you have any guesses on the short term stability?  (where short means left 
of your graph)

Suppose all those Chinese people hopped up and down on their chair in 
synchrony.  What would be the ideal timing?  I think I'm fishing for 
something like a chopper amplifier, but I'm not sure how I would explain a 
chopper to somebody who didn't know about them.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.