I'm speculating here, but I think the idea is to ascribe accuracy to processes, not to specific clocks.
So you make two clocks on the same principle, say pendulum oscillations, and measure how quickly they start to disagree. Then you make two clocks based on a new principle, say quartz oscillations, and measure their rate of disagreement. You'll notice that the two quartz clocks agree with each other better than the two pendulum clocks do. So quartz clocks keep time better than pendulum clocks.
Then you build a new type of clock, say of the atomic kind, and compare two atomic clocks to each other and to quartz clocks. As you repeat this process, I suppose the clock frequencies have to get progressively higher (Cesium clocks are measuring radiation at about 9 GHz), but this allows you to measure finer and finer discrepancies between them.
p1esk|4 years ago
puzzledobserver|4 years ago
So you make two clocks on the same principle, say pendulum oscillations, and measure how quickly they start to disagree. Then you make two clocks based on a new principle, say quartz oscillations, and measure their rate of disagreement. You'll notice that the two quartz clocks agree with each other better than the two pendulum clocks do. So quartz clocks keep time better than pendulum clocks.
Then you build a new type of clock, say of the atomic kind, and compare two atomic clocks to each other and to quartz clocks. As you repeat this process, I suppose the clock frequencies have to get progressively higher (Cesium clocks are measuring radiation at about 9 GHz), but this allows you to measure finer and finer discrepancies between them.
CheezeIt|4 years ago
CamperBob2|4 years ago
(No, really: with three uncorrelated clocks you can separate their variances.)
kingkawn|4 years ago