Using a state-of-the-art device for measuring mass, researchers have made their most precise determination yet of Planck's constant, an important value in science that will help to redefine the ...

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, ...

An upcoming change to SI units – due to be officially approved this month – will mark the end of a long journey from defining quantities in terms of objects to using precise, unchanging and universal ...