spaceSpace and Physics

The Values Of Four Fundamental Constants Are Going To Change


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockOct 24 2017, 15:15 UTC

This card shows the new values for the fundamental constants. Stoughton/NIST

We won’t notice but the values of four fundamental constants of the universe are going to change. Physicists around the world have revised the values of the electron's charge, the Boltzmann constant, the Planck Constant, and the Avogadro constant, all of which will play an important role in how we measure things.

The fine-tuning of these quantities was proposed by the International Committee for Weights and Measures and will be voted upon at the General Conference of Weights and Measures in November 2018. The vote will see an important shift in the way things are officially measured, a move that's been years in the making.


The updated values were obtained by the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants (TGFC). The electron's charge will help redefine the ampere, the unit of electrical current. The Boltzmann constant is used in thermodynamics and will help to redefine the Kelvin, the international unit for temperature. The Planck constant is the one that got people really excited because it will be key to the redefinition of the kilogram.

"The values of these four constants won't change anymore," Peter Mohr, a scientist at the National Institute of Standards and Technology (NIST) and a member of the CODATA TGFC, said in a statement.

"The whole thing is geared to not have any impact on the average person."


The impacts will be felt in the science world where the way the classic units are measured will help make more precise observations at the extreme ends of the scales. Tiny masses and extremely low temperatures will have a lot less uncertainty when measured.

"It's a broader philosophical paradigm shift," Mohr added. "When the speed of light became a fixed number, researchers stopped measuring the speed of light. They focused on realizing the meter. It's the same with the Planck constant. You're not going to be measuring the Planck constant anymore. You're going to be realizing mass and electrical standards more precisely."

The changes to the International System of Units are expected to be officially rolled out on May 20, 2019, which is World Metrology Day.

spaceSpace and Physics
  • tag
  • redefinition of the kilogram,

  • planck constant,

  • international system of units,

  • boltzmann constant,

  • Avogadro constant