Have you ever had a clock that runs a little fast, or a little slow? Well, technically speaking, every single timepiece you’ve ever owned is off, at least by a little bit. Time is actually such a strange thing that scientists are always searching for a new way to make a more accurate clock. And today, they have reached a level of precision that has been little more than a theory since the early 1980’s.
In 1981, scientist Hans Dehmelt developed the idea for an optical single-ion clock, which he predicted would be the most accurate timepiece, once someone built it. The idea was to utilize a laser which would trap individual ions. While devices based on this theory have been constructed, none were able to reach the accuracy that Dehmelt predicted, which was an uncertainty in the range of 1E-18.
To date, the most accurate clocks in the world have been made of caesium. They worked by using a pendulum of atoms which are excited by microwave radiation. These have been used in creating the actual definition of one second, which is the amount of time that passes during 9,192,631,770 cycles of the radiation produced from a caesium clock.
Recently, a group of scientists at the Physikalisch-Technische Bundesanstalt (PTB) have managed to construct the most accurate version of Dehmelt’s single-ion clock using ytterbium. It’s said to be roughly 100 times more accurate than any of the previous caesium clocks, and has an uncertainty in the range of 3 E-18.
But what good is an accurate clock if it eventually loses its accuracy, as all clocks will eventually do? Well, there’s nothing to worry about with PTB’s ytterbium clock. This bad boy won’t gain or lose a single second for at least a few billion years. By then, I’m sure we’ll have managed to create a new understanding of how the fabric of time can be measured and perceived.