The tick, tock of a strontium clock gets steadier

 作者:终先菟     |      日期:2019-03-15 01:10:00
By Celeste Biever YOU might think a clock with an accuracy of 1 second in 60 million years would be tough to beat. Yet atomic clocks using lattices of strontium atoms are poised to do just that, so becoming the gold standard for timekeeping. The clocks could allow more accurate GPS devices and new measurements of the fundamental constants that govern our universe. The best clocks at present are based on caesium and “tick” every time electrons in a single ion oscillate between energy states. That happens 9,192,631,770 times each second,