In a landmark decision, representatives from 60 countries voted to redefine the International System of Units (SI), changing the world's definition of the kilogram, the ampere, the kelvin and the ...

NEW LARGEST AND SMALLEST STANDARD UNITS OF MEASUREMENT. The prefixes make it easier to express large amounts – for example, always referring to a kilometre as 1,000 metres or a millimetre as one ...

A flaw in the system leaves physicists grappling with dimensionless units. Water is a precious resource. So protest erupted when, last September, India’s Supreme Court ordered Karnataka state to ...