Scientists from the Hubei Province said that they have assembled the country’s first optical clock. The optical clock measures time more precisely than the traditional atomic timekeepers.

The optical clock is based on the single calcium ion and can remain accurate within one second for more than ten million years. Gao Kelin, a researcher at the Hubei Academy of Sciences said that his group uses electric and magnetic fields to trap a calcium ion for more than 15 days. This allows the researchers to pinpoint the passage of time by tracking the ion’s atomic movement. The new development has made China the seventh country in the world to observe the optical range.