Category: Science

Science news from The New York Times. Get the latest developments about space, the environment, animal behavior, the brain, genetics, archeology and robots along with the weekly Science Times.

The Kilogram is Dead. Long Live the Kilogram!

Since 1889, Le Grand Okay, a smooth cylinder of platinum-iridium metallic, has dominated from its underground vault in Paris. An absolute monarch, it was the very definition of 1 kilogram of mass. Scientists from...