EUROPE — Every clock in your house probably tells a slightly different time. Now picture those clocks as the most precise instruments humanity has ever built, so accurate that they wouldn’t lose or ...

In a new study, researchers carried out the most extensive coordinated comparison of optical clocks to date by operating clocks and the links connecting them simultaneously across six countries.

In an effort to make keeping time even more accurate, researchers from six European countries joined forces to compare ten ultra-precise optical clocks at the same time — something that’s never been ...