Hi. This from the recent ShortWave Radiogram broadcast, may be of interest.
~ ~ ~ (Snipped stuff about other SI units undergoing a revamp...) Scientists now have their sights set on updating the unit of time: the second. Currently, the second is defined by atomic clocks made of cesium atoms. Those atoms absorb a certain frequency of light. The wiggling of the light's electromagnetic waves functions like the pendulum on a grandfather clock, rhythmically keeping time. One second is defined as 9,192,631,770 oscillations of the light. But a new generation of atomic clocks, known as optical atomic clocks, outdo the cesium clocks. "Their performance is a lot better than what currently defines the second," says physicist Andrew Ludlow of the National Institute of Standards and Technology in Boulder, Colo. Because those optical atomic clocks operate at a higher frequency, their "ticks" are more closely spaced, making them about 100 times more precise than cesium clocks. Ideally, the length of a second should be defined using the most precise timepieces available. A switch might happen in the late 2020s, Ludlow says. The change to the kilogram's definition was carefully orchestrated so that it wouldn't affect normal people: A kilogram of flour still makes the same number of biscuits. Any change to the second will be similarly coordinated. So, sorry, there'll be no chance to squeeze any extra seconds into a day. https://www.sciencenews.org/article/kilogram-just-got-revamp-unit-time-might-be-next ~ ~ ~ So, perhaps a host of surplus cesium clocks on the market at some point? 73 Dave B G0WBX. -- Created on and sent from a Unix like PC running and using free and open source software: _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
