The global system of measurements has been overhauled with new definitions for the kilogramme and other key units.
World scientists for whom the update represents decades of work clapped, cheered and even wept as the 50-plus nations one by one said "yes" or "oui" to the update.
Nobel prize victor William Phillips called it "the greatest revolution in measurement since the French revolution", which ushered in the metric system of meters and kilograms.
That's all expected to change on Friday as the International Bureau of Weights and Measures, an intergovernmental organization based in Paris, votes to redefine the kilogram. Scientists at the meeting were giddy with excitement: some even sported tattoos on their forearms to mark the moment. Their bathroom scales won't get kinder and kilos and grams won't change in supermarkets.
The head of BIPM (International Bureau of Weights and Measures) Martin J.T. Milton holds a replica of the International Prototype Kilogram in Sevres, near Paris. U.S. President Benjamin Harrison was given a copy of Le Grand K the same year.
The new definitions will be put into place on May 20th, 2019.
Unlike a physical object, the formula can not pick up particles of dust, decay with time or be dropped and damaged.
"The same is true when you get down to very small masses like a milligram - for example the active ingredients of pharmaceuticals".
Up to now, it has been defined by a weight of a platinum-based ingot called "Le Grand K" locked in a vault in France, but now the baseline measure is "going electronic". For one thing, you can't just ask the French to send you the reference article every time you want to run an experiment-scientists needed precise measuring units they could generate for themselves, wherever they were.
Only exceedingly rarely have they seen the light of day since 1889, when they were taken out on a very few occasions to check whether other master kilograms that nations around the world use were still accurately calibrated, give or take the mass of a dust particle or two.
Humankind is about to sever one of the links between its present and its past.