Upgraded atomic clock won’t lose a second for 15 billion years

An atomic clock located at the University of Colorado in Boulder is now the most accurate timepiece of its kind in the world, according to a new study published in the journal Nature Communications. How accurate is it? When the universe is more than twice as old as it is now, this clock won’t have lost or gained even a single second. Now that’s something you can set your watch to.

This clock set records for accuracy when it was first brought online a year ago, but recent improvements have led to new records being set. It is roughly three times as accurate now. The most trusted international standard for timekeeping is still the caesium fountain atomic clock, but this new record-breaking clock is what’s known as an “optical lattice” clock, which uses strontium atoms in place of caesium.

Each element has a different vibrational frequency, and this is used to mark the passage of time. The clock detailed in the new study — created and optimized with the help of the National Institute of Standards and Technology (NIST) — measures the oscillations of strontium atoms by suspending them in a red laser. The accuracy was improved by using a more stable laser emitter and shielding the measurement chamber from electromagnetic radiation, among other things.

The optical lattice clock is now so accurate that it can measure the effects of time dilation here on Earth as predicted by General Relativity. We know that gravity and acceleration cause time to pass more slowly, which is why astronauts aboard the International Space Station experience the passage of time ever so slightly slower than we do on Earth (because it’s moving so fast in orbit). The clock in this study is able to measure the time dilation effects of being raised or lowered just 2cm due to the miniscule gravitational changes of being closer or farther from the Earth’s surface.

There’s a certain amount of healthy scientific competition buildingthe most accurate clock in the world, but it also has practical uses. Beyond keeping the world’s time, an accurate atomic clock is necessary for communications synchronization, GPS navigation, and a plethora of scientific experiments. With a little more refinement, the optical lattice clock could soon supplant caesium fountains as the de facto standard.