> How do we know which is the more accurate timekeeper? > > Keep in mind we have no other units to compare with. Only these two.
If there is only one clock -- that is the exact time and you are sure of it (and strictly speaking, in this case, the word "accuracy" doesn't apply). If you have two clocks, only two clock, and no other reference point, then you cannot tell which is the more accurate. But, you can still tell how well they agree. And in many cases having an upper bound on their error is itself important information. You can get this simply by comparing the two clocks. One can serve as a check of the other, etc. To get a better idea which one clock is the best, you need to add another clock to the mix. If you do pair-wise comparisons among them it's usually quite easy to tell which of the three is the worst or which of the three is best. If they all appear to be equally accurate, then they probably are all equally accurate, in which case the mean of all three (an ensemble clock) is better than any one of the three. Now you know why UTC is a sort of mean of some 150 atomic clocks around the world. > The reason for my question? How do we know when > someone has invented a more accurate device to > measure time? Usually you compare it to your previous best clock or clocks. Or you build two or three identical new clocks and intercompare them. /tvb _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
