Since the 19th century, scientists have based their definition of the fundamental unit of mass on a physical object — a shining platinum iridium cylinder stored in a locked vault in the bowels of the ...

There is a new standard in town, and it's sort of a big deal. This new standard is the definition of the kilogram, the unit of mass in the SI system—the International System of Units). It replaces the ...

The U.S. National Institute of Standards and Technology called this Friday a “turning point for humanity,” even though the difference between this day and the day before weighs, theoretically, nothing ...

The kilogram — anywhere in the world, for any purpose — is based on the exact weight of a golf-ball-sized chunk of platinum and iridium stored under three glass bell jars in a vault in an ornate ...

Talk about massive change. After meeting the needs of science, industry and commerce for more than 130 years, the kilogram has just been fundamentally reinvented. At a meeting Friday in Versailles, ...

The big science-y news of last week was the vote to officially redefine of the kilogram-- see the stories in Physics World and Physics Today for more detail--after decades of work by physicists on ...

We measure stuff all the time—how long, how heavy, how hot, and so on—because we need to for things such as trade, health and knowledge. But making sure our measurements compare apples with apples has ...

Since 1889, human civilization has depended upon a magic rock. Known as Le Grand K, it sits under protective glass in St. Cloud, France. Humanity's magic rock is actually a chunk of metallic alloy ...

In a subterranean vault in a suburb of Paris lies a small, rarely seen metal cylinder known as Le Grand K. For 130 years, this golf-ball-sized hunk of 90% platinum and 10% iridium has served as the ...