It’s the end of an era. After 130 years of faithful service, the so-called “prototype kilogram” upon which nations base their weight measurements was just replaced by a new standard based on ...

There is a new standard in town, and it's sort of a big deal. This new standard is the definition of the kilogram, the unit of mass in the SI system—the International System of Units). It replaces the ...

In addition to Ampere, Kelvin, Mol and Co., the kilogram also is now defined by a natural constant. In concrete terms, this means that the original kilogram, which has been the measure of all things ...

In addition to other scientific units, the kilogram also is now defined by a natural constant. This is made possible by single crystals grown from highly enriched silicon-28. In addition to Ampere, ...