Is a meter a meter and a second a second? Yes, but they will be defined differently from May 20th on. This marks the beginning of a new era for science. New rules have been in force since May 20th: ...

Scientists voted on Friday to redefine it based on electric currents. A replica of the International Prototype Kilogram is pictured is seen at the 26th meeting of the General Conference on Weights and ...

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 ...