The Kilogram is dead! After a vote, standard measure for mass is redefined

A one-kilogram sphere of single-crystal silicon, one of the roundest man-made objects in the world. The object helped redefine a kilogram in terms of the number of atoms it contains

Since 1889, Le Grand K, a sleek cylinder of platinum-iridium metal, has ruled from its underground vault in Paris. An absolute monarch, it was the very definition of one kilogram of mass. Scientists from around the world made pilgrimages to it, bringing along their national kilogram standards to weigh in comparison.

“The mother ship is never wrong,” said Robert Vocke Jr., a chemist at the National Institute of Standards and Technology (N.I.S.T.) in Gaithersburg, MD.

No longer. Friday, in a small conference center located just steps from the Palace of Versailles, several dozen nations voted to overthrow Le Grand K and to