Adopting the International System of Units to the 21st century

Published

March 1, 2011

Author(s)

Peter J. Mohr, Ian M. Mills, Terry Quinn, Barry N. Taylor, Edwin R. Williams

Abstract

We review the proposal of the International Committee for Weights and Measures (CIPM), currently being considered by the General Conference on Weights and Measures (CGPM), to revise the International System of Units, the SI. The proposal includes new definitions for four of the seven base units of the SI, and a new form of words to present the definition of all the units. The objective of the proposed changes is to adopt definitions referenced to the fundamental constants of physics, taken in the widest sense, so that the definitions may be based on true invariants of nature. The importance of relations among the fundamental constants to the definitions, and the importance of establishing a mise en pratique for the realization of each definition, is also discussed.

Citation

Proceedings of the Royal Society A-Mathematical Physical and Engineering Sciences

Issue

3907-3924

Pub Type

Journals

Keywords

International System of Units, SI, new SI, definition of the new SI, fundamental constant, SI reference constant, explicit constant definition, explicit unit definition

Citation

Mohr, P. , Mills, I. , Quinn, T. , Taylor, B. and Williams, E. (2011), Adopting the International System of Units to the 21st century, Proceedings of the Royal Society A-Mathematical Physical and Engineering Sciences (Accessed October 13, 2025)