Azerbaijan National Academy of Sciences

Physicists in Germany have built the most accurate timepiece on Earth, achieving unprecedented levels of accuracy with a new atomic clock that keeps time according to the movements of ytterbium ions.

Called an optical single-ion clock, the device works by measuring the vibrational frequency of ytterbium ions as they oscillate back and forth hundreds of trillions times per second between two different energy levels. These ions are trapped within an 'optical lattice' of laser beams that allows scientists to count the number of ytterbium 'ticks' per second to measure time so accurately, the clock won’t lose or gain a second in several billion years.

Until very recently, our most accurate time-keepers were caesium atomic clocks - devices that contain a 'pendulum' of atoms that are excited into resonance by microwave radiation. It's on these clocks that the official definition of the second - the Standard International (SI) unit of time - is based.

According to the most accurate caesium atomic clock in the world, 1 second is the time that elapses during 9,192,631,770 cycles of the radiation produced by the transition between two levels of the caesium 133 atom.

That might sound pretty good, but when it comes to defining time itself - the thing that governs literally everything we do in life - you can never be too accurate.

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