Japan clocks keep time for 16 billion years

Tokyo - Japanese researchers have built a pair of clocks which they say are so accurate they will lose a second only every 16 billion years - longer than the Earth has been around.

"Cryogenic optical lattice clocks" are not pretty - they look more like giant stripped-down desktop computers than ordinary wall clocks - but they are so precise that current technology cannot even measure them.

The research team led by Hidetoshi Katori, a professor at the University of Tokyo, believes it has taken the technology way beyond the atomic clocks that are currently used to define the "second".

The new clock uses special lasers to trap strontium atoms in tiny grid-like structures, according to the team, which published the study this month in the journal Nature Photonics.

It then measures the frequency of the vibration of the atoms, using them like "the atomic pendulum", according to the study.

The system is so delicate that it must operate in a cold environment, around -180°, to reduce the impact of the surrounding electromagnetic waves and to maintain the machine's accuracy, the team said.

Researchers connected the two clocks for a month, and estimated that it would take some 16 billion years for them to develop a one-second gap.

That is significantly more accurate than the caesium atom clock, used to define "one second", which can develop a one second error every 30 million years, they said.

The technology could be applied to satellite-based global positioning systems and communications networks, while also serving as a foundation for various precision technologies, the team said in a statement.

"Through improved precision, we hold high hopes for accelerated discussions on redefinition of the 'second'," the statement said.