Redefining time
WASHINGTON, April 30--Atomic clocks based on the oscillations of a cesium atom keep amazingly steady time and also define the precise length of a second. But cesium clocks are no longer the most accurate. That title has been transferred to an optical clock housed at the U.S. National Institute of Standards and Technology (NIST) in Boulder, Colo. that can keep time to within 1 second in 3.7 billion years. Before this newfound precision can redefine the second, or lead to new applications like ultra-precise navigation, the system used to communicate time around the globe ...




