"But later this week, on Friday, November 16th, a coup is planned in this international ministry of weights. After having served for 129 years as the world’s standard, the International Prototype Kilogram (or Le Grand K, as it’s known locally) will be stood down. Grandees of the International Bureau of Weights and Measures, which regulates the metric system, will gather in Versailles and vote to replace this physical artifact with a definition of the kilogram based on a fundamental constant of nature."

"The switch won’t be noticed by anyone outside of an advanced physics lab, but is a momentous occasion for those involved. “It is the Halley’s Comet of metrology,” says Stephan Schlamminger, a physicist from the US National Institute of Standards and Technology (NIST) who worked on the equipment used for the coming changeover. “It’s incredibly rare that a redefinition of this magnitude happens.” "