WASHINGTON — Earth’s changing spin is threatening to toy with our sense of time, clocks and computerized society in an unprecedented way — but only for a second. For the first time in history, world ...

Add Yahoo as a preferred source to see more of our stories on Google. Somebody adjusting the minute hand on a clock hanging on a yellow wall. The leap second – units of time added to the atomic clock ...

For decades we have measured the length of a second in two ways. In Astronomical timekeeping, one second equals the amount of time it takes to complete one rotation (midnight to midnight, noon to noon ...

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