General Conference on Weights and Measures expands range of SI unit prefixes with Ronna and Quetta
Measurement scientists and government representatives have gathered at the General Conference on Weights and Measures (CGPM) in Versailles, France, and agreed to expand the range of prefixes within the International System of Units (SI).
Dr Richard Brown, Head of Metrology at the National Physical Laboratory (NPL), the UK’s national metrology institute, led the proposal recommending the new names – ronna and quetta – as SI prefixes for 10^27 and 10^30, respectively. They are joined by their microscopic counterparts, ronto for 10^−27, and quecto for 10^−30. The proposal was approved by the CGPM and these new prefixes have been incorporated into the SI with immediate effect, becoming the first expansion to the range of SI prefixes since 1991.
The expansion has been driven by the requirements of data science, digital storage and the exponentially growing size of the global datasphere, which is already using prefixes at the top of the existing scale. Additionally, the prefixes for very small numbers are useful for quantum science and particle physics.
The International System of Units (SI) is the only system of measurement units accepted worldwide and provides units for every type of measurement. As the UK’s National Metrology Institute, NPL is responsible for maintaining and developing the UK’s primary measurement standards for SI units and ensuring their comparability internationally.
According to Brown, SI prefixes have expanded over the years in response to advances in science and technology requiring access to an increased range of orders of magnitude relating to measurement.
“These new SI prefixes will allow clear and unambiguous communication of these measurements for many years to come,” he concludes