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 ...

How do you define one kilogram? Easy: it's the exact mass of a metal cylinder called the International Prototype Kilogram, IPK for short, kept in controlled conditions in France. But the standard ...

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 ...

“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 ...

They will be the earth’s roundest spheres, crafted by Australian scientists as part of an international hunt to find a new global standard kilogram. Ever since scientists discovered that the current ...

The meter is fixed to the speed of light and a second to the radiation of cesium , but the mass of one kilogram is still not defined by a universal constant. Instead, it's still pegged to an ...