Weighty matters: a platinum-iridium kilogram belonging to the US National Institute of standards and Technology. (Courtesy: J.L. Lee/NIST) Metrologists and policy-makers from 60 countries around the ...

A nanometer (nm) is a unit of length in the metric system, defined as one billionth (10-9) of a meter (m). The meter is the base unit of length in the International System of Units (SI), making the ...

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 ...

New prefixes for the world’s largest and smallest numbers have been confirmed by a vote at the General Conference on Weights and Measures (CGPM) in Versailles, France, on Friday. The suggested ...