"If ever you wanted to set your watch, now is the time." Leon Lobo, of Britain's National Physical Laboratory (NPL), stands before a rack of servers near Canary Wharf, London's eastern financial outpost. The rack holds a high-precision, caesium atomic clock-the most accurate sort on the planet-and two other digital timepieces, called "grandmaster clocks", that work alongside it. Ticking in synchrony, all three display the time to within a whisker of coordinated universal time (UTC), the world's absolute standard.
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