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 ...

For decades, metrologists have strived to retire ‘Le Grand K’ — the platinum and iridium cylinder that for 126 years has defined the kilogram from a high-security vault outside Paris. Now it looks as ...

The International Committee for Weights and Measures is about to reach a decision that could affect the teaching and understanding of basic science for the next hundred years. It has passed a ...

The NIST-4 Kibble balance, an electromagnetic weighing machine that is used to measure Planck's constant, and in turn, redefine the kilogram. Jennifer Lauren Lee / NIST Locked in a vault that requires ...

Redefinition of the kilogram will not make the kilogram more precise, but it will make it more stable. A physical object can lose or gain atoms over time, or be destroyed, but constants remain the ...

The official definition of a kilogram has been changing for well over a century, but this week it may be redefined for the final time. After years of debate and discussion, scientists from around the ...