The 26th General Conference of Weights and Measures voted to redefine four SI base units – kilogram, ampere, kelvin, and mole – based on natural constants rather than physical artifacts. The changes will take effect on May 20, 2019, World Metrology Day. The kilogram, currently defined by a physical artifact (Le Grand K), will be redefined using the Planck constant, speed of light, and cesium atom’s microwave radiation. The ampere will be based on the electron charge constant, kelvin on quantum atomic motion, and mole on Avogadro’s constant. This will allow more accurate measurements for electronics and pharmaceuticals, with benefits for GPS, drug design, and quantum-level scaling.
Keywords: Metrology, Quantum, Constants, Precision, Measurement
