Scientists compared three different types of atomic clocks to the nearest 1 / 1,000,000,000,000,000,000th of a second. Not only does this mean a more accurate definition of the second, but it also means a more accurate measurement of, among other things, sea levels. It might even help in searching for dark matter.

Currently, the duration of one second is specified in the cesium atomic hour, which is accurate to sixteen decimal places. This means it takes 138 million years to advance or delay one second.

This is very accurate, you think. But if you use other atoms, such as aluminum, strontium, or ytterbium, an accuracy of up to eighteen decimal places can be achieved. Hundred times a minute. Such a clock would take billions of years to skip a step in one second.

### What is the atomic clock?

An atomic clock measures the vibrations of atoms. Atoms absorb and scatter photons as they travel from one energy state to another. This process is not only very regular, but also environmentally independent. By measuring vibrations, you can measure the course of time with great accuracy.

With such a watch, you will know more precisely how long a second lasts. But before you can determine the second more preciselyHOf course, those different atomic clocks must first be compared with each other. This has not worked sufficiently yet, for “only” seventeen decimal places.

Researchers in Boulder, Colorado have now overcome this hurdle and compared three hours to eighteen decimal places. So it is possible that the current atomic cesium clock will soon regress, after which the aluminum, strontium, or ytterbium atomic clock could take over.

### How do we measure time?

For the elite athlete, fractions of a second can make the difference between eternal fame and the place next to the podium. But computers, GPS, exchanges and companies cannot do without accurate time measurements. NPO knowledge He explains How do we measure time.

## Also practical applications

This also has possible practical applications. For example, the frequency of an atomic clock depends on the gravitational pull and therefore the height at which it is located. By comparing the frequencies of two of these atomic clocks, you can determine height differences of just a few centimeters. This way, you can measure the level of oceans or glaciers very precisely.

In fact, physicists are secretly hoping that the new watches will help find the mysterious dark matter. This is never noticed, but it should be there. The new clocks may be accurate enough to measure interactions between atoms and dark matter.

*Related: *

### Will we finally find dark matter?

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