We’ve long known that there were some issues with France’s ‘Le Grand K’, the international prototype for what a kilogram really is. Made in 1879 from platinum and iridium alloy, it is the perfect ...

“The mother ship is never wrong,” said Robert Vocke Jr, a chemist at the National Institute of Standards and Technology in Gaithersburg, Maryland. No longer. Friday, in a small conference centre just ...

France holds the world’s standard for the kilogram weight. It’s a cylinder-shaped object that has dictated all other kilogram weights for 130 years now. As it’s made from platinum-iridium though, the ...