On November 16, 2018, delegates at the General Conference on Weights and Measures voted to redefine the kilogram, ampere, kelvin and mole using natural constants. The vote was the news; implementation was scheduled for May 20, 2019. That distinction matters: the new system was not yet in force when NIST reported the decision. The kilogram’s old reference was a platinum-iridium object kept near Paris. If a physical standard changes as it absorbs material or is cleaned, every calibration chain inherits a problem: the reference itself can drift. A definition tied to constants is intended to make the unit reproducible beyond one object. The second and meter already relied on natural phenomena, so this was not a wholesale departure from artifact-based units. For businesses, reliable calibration underpins comparable measurements across suppliers, instruments and borders. But NIST said consumers and most industries would notice no immediate effect; it presented lower calibration costs and new technology as expected benefits, not realized savings. The change could improve the measurement infrastructure without making entry cheaper by itself. Whether it lowers costs broadly depends on implementation and access to capable calibration services—outcomes this 2018 report could not establish. [shared-ef195e14365b6120e32d6a19c228816424ec853a18b3ad52bf4a0d18e73a3f33]
Technology
When the kilogram stops depending on one object
A November 2018 international vote set a later shift from an artifact kilogram to definitions tied to natural constants, promising more stable measurement without an immediate change for most buyers.
Published by Glen Wire
An editorial point of view: Theo Arden