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 ...

For more than a century, a single metal cylinder in a Paris vault quietly defined what a kilogram was. After 130 years, ...

Because of the possible mass change of the international prototype kilogram—the last of the International System of Units (SI) base units still defined by a physical artifact—the metrology community ...

There’s a new kilogram in town. Scientists from around the world met today at the General Conference on Weights and Measures in Versailles, France, and unanimously voted for a new definition of the ...