Precision clock traps atoms in light to keep time

By Julie Steenhuysen

CHICAGO (Reuters) - U.S. physicists have made a clock so accurate it will neither gain nor lose even a second in more than 200 million years, a finding sure to please even the most punctually minded.

The clock, described in the Friday issue of the journal Science, outperforms the official atomic clock used by the U.S. Commerce Department's National Institute of Standards and Technology, which promises to keep accurate time down to the second for 80 million years.

The new atomic clock is vying for the title of world's most accurate with another experimental clock developed in the same lab at the Joint Institute for Laboratory Astrophysics, a collaboration between NIST and the University of Colorado in Boulder.

"These clocks are improving so rapidly that it is impossible to tell which one will be the best," said Tom 0'Brian, head of the Time and Frequency Division at NIST.

Such highly precise clocks are critical for deep space navigation, where even a slight error can make or break a space mission.

The secret to making an extremely accurate clock is speeding up how fast it ticks. "If you make a mistake, you can know about that mistake very fast," said Jun Ye, who developed the atomic clock at JILA.

Ye's clock has 430 trillion "ticks" per second.

Its pendulum uses thousands of strontium atoms suspended in grids of laser light. This allows the researchers to trap the atoms and measure the movement of energy inside.