Everyday Scientist

a better atomic clock

Researchers from NIST in Bolder, CO have produced a high-precision clock using a single Hg atom, which they claim out-precisions the standard Cs clock which we currently use to define the second. They use a UV laser (as opposed to the microwave laser used for the Cs clock) to excite the atom, which means that the frequency can be known with greater precison. The frequency of the UV transition was measured to be 1,064,721,609,899,144.64 Hz—oops, I wrote that wrong, it’s actually 1,064,721,609,899,144.94 Hz.

According to Nature, “the clock is expected to drift by only 1 second in 400 million years compared with 1 in 60 million in caesium clocks.” Well thank god.