[time-nuts] What's the time Mr Wolf...

[tomknox at nist.gov]

Hi Steve;
I think God decides the time the fun parts is watching humans try to  
sort it out.
Currently the World has accept a specific number of vibrations  
(9,192,631,770) of a Cesium-133 atom to define one second. For the USA  
the master clock F1 is in Colorado and although the GPS sat's are  
monitored in Colorado their onboard clocks are Checked and corrected  
from Texas.
Best Wishes;
Thomas Knox




Quoting "Steve Rooke" <sar10538 at gmail.com>:

> Hi,
>
> This may have already been covered in this group so please excuse me
> for not combing the archives. I could Google for this but I'll get a
> quicker answer here and I know it will be the correct one.
>
> !) Who decides on what is the correct time?
> 2) Is the time standard stored on one master grandfather clock?
> 3) As (2) is unlikely, if a number of clocks are involved, are they in
> different countries?
> 4) As (3) is likely, how are they synchronised?
> 5) If this involves communicating with each other, what medium is used
> and how are delays handled (a la NTP pings)?
> 6) If all the clocks are synchronised in one place and then
> transported all over the World, how is the Einstein affect of time
> dilation handled due to the clocks changing in flight?
>
> Now the interesting ones (for me anyway).
>
> 7) Where are the clock(s) located which provide the time for the GPS  
> satellites?
> 8) If they are actually in the satellites, how are they all kept
> synchronised with each other and the "master grandfather clock" on the
> ground?
> 9) Are the satellites in geostationary orbit?
> 10) If they are geostationary, or move in relation to the ground, how
> are the affects of the Einstein time dilation handled as they may be
> travelling at a different speed than a point on the surface of the
> Earth?
> 11) Extrapolating this, a point on the Equator would be moving faster
> that a point at the poles or even Greenwich, for that matter. So would
> a clock at each location move out of synchronisation with each other?
>
> Aren't you glad I'm back :) BTW, where is /tvb these days, I haven't
> seen any postings by him while I have catching up?
>
> 73
> Steve - ZL3TUV
> --
> Steve Rooke - ZL3TUV & G8KVD
> Omnium finis imminet
>
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