If scientists had sacred objects, this would be one of them: a single, closely guarded 137-year-old cylinder of metal, housed in a vault outside of Paris. It is a prototype that precisely defines a ...

A group of Brazilian researchers has presented an innovative proposal to resolve a decades-old debate among theoretical physicists: how many fundamental constants are needed to describe the observable ...

I HAVE recently been laying stress on the fact that the fundamental equations of mechanics and physics express relations among quantities, and are independent of the mode of measurement of such ...