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10.22.2018
By explicitly connecting all base units to fundamental constants, the future reform of the International System of Units (SI) will complete the objectives of universality and stability sought by the...
10.15.2018
On November 13-16, 2018 in Versailles, the base units of the International System were set to be redefined in reference to seven physical constants. A look back at the reasons and issues involved in...
10.13.2017
50 years ago, on October 13, 1967, the second—the unit of time—was no longer defined by stars, but by atoms. In this quest for precision, scientists are now inventing the clocks of the future,...