Atomic clocks are the basis upon which a second is defined. But there is a new kid on the block, the optical clock, which ...

Modern timekeeping relies on the accuracy of atomic clocks, which revolutionized timekeeping by using the quantum behavior of atoms to measure time. Discover how these incredibly precise clocks ...

ESA's Atomic Clock Ensemble in Space (ACES ... from the outside of ESA's Columbus module on the International Space Station, measuring time from orbit with unprecedented precision.