‘Grand K’ kilo retired with overhaul of measurements
VERSAILLES, France — In a historic vote, nations on Friday unanimously approved a ground-breaking overhaul to the international system of measurements that underpins global trade and other vital human endeavors, uniting together behind new scientific definitions for the kilogram and other units.
Scientists, for whom the update represents decades of work, clapped, cheered and even wept as the 50-plus nations gathered in Versailles, west of Paris, one by one said “yes” or “oui” to the change, hailed as a revolution for how humanity measures and quantifies its world.
The redefinition of the kilogram, the globally approved unit of mass, was the mostly hotly anticipated change. For more than a century, the kilogram has been defined as the mass of a cylinder of platinumiridium alloy kept in a high-security vault in France. That artifact, nicknamed “Le Grand K,” has been the world’s sole true kilogram since 1889.
But now, with the vote, the kilogram and all of the other main measurement units will be defined using numerical values that fit handily onto a wallet card. Those numbers were read to the national delegates before they voted.
Nobel prize winner William Phillips called the update “the greatest revolution in measurement since the French revolution,” which ushered in the metric system of meters and kilograms.
The change will have no discernable impact for most people. Bathroom scales won’t suddenly get kinder and kilos and grams won’t change in supermarkets.
But the new formulabased definition of the kilogram will have multiple advantages over the precision-crafted metal lump that set the standard from the 19th century to the 21st. Unlike a physical object, the new formula for the kilo cannot pick up particles of dust, decay with time or be damaged.