Precision timekeeping has moved on from atomic clocks to optical atomic clocks, which are a big step forward. What these instruments can do to keep accurate time has been getting better and better over the last few years. They are now at an amazing level that is far above what regular atomic clocks can do.

Atomic clocks use cesium atoms that have been cooled almost to absolute zero. Being able to measure the resonant frequency of these atoms lets it keep time. Most atomic clocks don't go off by more than one second every 300 million years. Scientists realized they could do better, though. They found that a "web of light," or optical lattice, could be used to trap and measure tens of thousands of atoms.

There are 40,000 strontium atoms in this lattice, which is only a tiny bit above absolute zero. The ticking of this clock is the electrons in this atom moving from one level of energy to another. With an error of only 8.1 parts per tenth of a billionth of a billionth, researchers were able to measure time.

You might be wondering why being so precise is helpful. Aren't atomic clocks accurate enough for people? Yes and no are the answers. Atomic clocks are very accurate, which has made many parts of our lives easier. One that is used a lot is GPS. If optical clocks were used instead, they would make accuracy at least 1,000 times better. But it will also give us new ways to test basic physics.

"There will be very interesting discoveries waiting for us if we get to the times that are sensitive to the very small space-time curvature," Professor Jun Ye told IFLScience when he won the 2022 Breakthrough Prize in Fundamental Physics. He is a senior author on the paper.

One thing that could be done is to study general relativity with these clocks. Some atomic clocks, like those on GPS satellites, already experience this, but the extra accuracy lets us check our assumptions more thoroughly and maybe see things we haven't seen before.

Ye said in a statement, "We're exploring the edges of measurement science." "When you can measure things with this much accuracy, you start to see things that we could only guess about before."

This clock is so accurate that it can detect effects that are so minute that theories like general relativity can explain them, even at the microscopic level. It's testing the limits of what's possible with keeping track of time.

In the map app on your phone, accuracy might not seem very important, but it will make a big difference as people continue to explore the solar system. It could be the start of big steps forward in quantum computing.

Ye, from the National Institute of Standards and Technology and the University of Colorado Boulder, said, "If we want to land a spacecraft on Mars with pinpoint accuracy, we'll need clocks that are orders of magnitude more accurate than what we have now in GPS." "This new clock is a big step in the right direction."

The results will be written up in a paper that will come out next week in Physical Review Letters.