From: Georgi Guninski <gunin...@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. This is related: https://en.wikipedia.org/wiki/Einstein_synchronisation Interesting side-side-issue: https://en.wikipedia.org/wiki/Quantum_entanglement Scientists have continued to experiment with the use of optical fibers to study quantumentanglement. http://phys.org/news/2008-06-world-largest-quantum-bell-spans.html(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 secondmeasurement 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 wereat 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'tchanging) then very good results can obviously be obtained using the far more mundanesystem. Interesting tidbit: A 1 centimeter change in the altitude of a clock, at about the Earth'ssurface, changes the rate of that clock by about 1 part in 10E18. (My own calculation: Itmight be a factor of 2 off.) Experimental clocks of approximately this accuracy exist.http://www.nature.com/nature/journal/vaop/ncurrent/abs/nature12941.html?message-global=remove In addition, "nuclear clocks" are talked about. (although they are somewhat hard toGoogle-search because of term confusion with the "Doomsday Clock". here's an example:http://www.forbes.com/sites/chadorzel/2016/05/17/why-do-physicists-want-a-nuclear-clock/#2dc823e1d0b5 Jim Bell
