The metric system is on track for a mass makeover. In an effort to provide accurate measurements at all scales, scientists are preparing to redefine four basic units by the end of 2018. The shift will ...

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 ...

In the biggest overhaul of the international system of units since 1875, countries have voted to redefine four basic units of measurement — the ampere, the kilogram, the kelvin and the mole. At a ...