Nasa, in collaboration with the European Space Agency (ESA), has launched two state-of-the-art atomic clocks to the International Space Station (ISS) as part of the Atomic Clock Ensemble in Space ...

"This book provides a introduction to the physics of time and time measurement, from an historical perspective to the modern day. It discusses the stability and accuracy of atomic frequency standards, ...

China’s strontium optical clock now participates directly in international atomic time calculation Optical clocks operate at higher frequencies than caesium, allowing finer measurement resolution ...