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Scientists Change Definition of the ‘Second’ | ASHARQ AL-AWSAT English Archive 2005 -2017
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London-What’s the length of a second? Scientists continue to ask themselves this question because no matter how accurately time is measured, there would still be an error of about a nanosecond every 30 days.

Researchers in Germany said in a paper published in the journal Optica that the second becomes more accurate if they drop the measurement of time based on the atomic cesium clock and resort to the optical clock.

Since 1967, the International System of Units (SI) has defined the second as the time that elapses during 9,192,631,770 cycles of the microwave signal produced by these oscillations.

However, just like a traditional pendulum clock, they can run fast or slow with an error of about a nanosecond every 30 days.

The new optical clock ticks so consistently that if it had started at the dawn of the universe, it would have lost less than two minutes.

Dr. Christian Grebing, of The National Metrology Institute of Germany who worked on the new clock, said: “Our study is a milestone in terms of practical implementation of optical clocks.”

“The message is that we could today implement these optical clocks into the time-keeping infrastructure that we have now, and we would gain,” he added.