Redefinition of the kilogram will not make the kilogram more precise, but it will make it more stable. A physical object can lose or gain atoms over time, or be destroyed, but constants remain the ...

Deep underneath the Parisian suburb of Saint-Cloud, in a vault that can only be opened by three people wielding three different keys, there lies a hunk of metal that is so crucial to the world of ...

Constants are supposed to be, well, constant. In physics there are a number of fundamental constants, such as the speed of light, Planck's constant, and the charge of an electron that are essential to ...

Detecting or constraining the possible time variations of fundamental physical constants is an important step toward a complete understanding of basic physics and hence the world in which we live. A ...