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Tests of time The world's first nuclear clock is on the horizon It would be 1000 times more accurate than today's atomic timekeepers FOR THE discerning timekeeper, only an atomic clock will do. Whereas the best quartz timepieces will lose a millisecond every six weeks, an atomic clock might not lose a thousandth of one in a decade. Such devices underpin everything from GPS and the internet to stock-market trading. That may seem good enough for most. But in a paper recently published in Nature, researchers report being ready to build its successor: the nuclear clock. Ekkehard Peik, one of the field's pioneers, says such a clock could be a factor of 1,000 times better than today's standard atomic clocks. In atomic clocks, the electrons around an atom's nucleus are jolted into a higher energy state by incoming radiation of a specific frequency. Each wave cycle of the radiation therefore corresponds to a “tick” measuring a small fraction of a second. Nuclear clocks would follow the sam
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