From: Georgi Guninski <guninski@guninski.com>
>To get it, you use the network which is of unknown latency (unless you
>sniff it).
>To get the system time you must know:
>1. When you got the time
>2. When you received the time

>Something like Eisenstein's theory about impossibility to synchronize
>clocks with super-light speed. Sometimes I wonder what is so special
>about the speed of light and if humans were blind per design and didn't
>know what light is, would they replace "speed of light with 'speed of
>fastest thing they can measure", explaining relativity with "the fast
>thing slows down near `matter'" ;) (this paragraph is just trolling).

As I recall, it is impossible to (perfectly) synchronize a rotating assemblage of clocks.
Since Earth is rotating, that means all clocks on it (except at the poles) are rotating, too. 


Scientists have continued to experiment with the use of optical fibers to study quantum
(no relation, of course)  They generated photon-pairs which were quantum-entangled,
 sent them in opposite directions, made their measurements far away, and found
(as they kinda-sorta expected) that the first measurement somehow affected the second
measurement many kilometers away.

I read a few years ago, somewhere, that in such a test they were able to exclude the 
possibility of a direct-communication effect manipulating the results unless it were
at a speed of at least 10,000 c (10,000x the speed of light in a vacuum.)

Perhaps this system could be used to synchronize clocks.  Although, since the speed
 of light in an optical fiber is very constant over time (assuming the temperature isn't
changing) then very good results can obviously be obtained using the far more mundane
system.

Interesting tidbit:  A 1 centimeter change in the altitude of a clock, at about the Earth's
surface, changes the rate of that clock by about 1 part in 10E18.   (My own calculation:  It
might be a factor of 2 off.)    Experimental clocks of approximately this accuracy exist.

In addition, "nuclear clocks" are talked about.  (although they are somewhat hard to
Google-search because of term confusion with the "Doomsday Clock".  here's an example:

              Jim Bell