Index

DEFININGCONSTANT: speed of light in vacuum

  • PID: si:definingconstant:speed_of_light_vacuum:2019
  • Definition: The speed of light in vacuum, c, is exactly 299 792 458 m/s.
  • Source: SI Brochure 9th Ed. 2019, p 127
  • Formatted: 299 792 458 m s-1
  • Numerical Value: 299792458
  • Unit: m s-1
  • Unit in Base SI: m s-1
  • Notes
    1. This value was fixed by the CGPM in 1983 (Resolution 1) and reiterated by the CGPM in 2018 (Resolution 1).
    2. The speed of light in vacuum is a fundamental constant that determines space-time properties and affects all particles and fields equally on all scales and in all environments.
  • Related Definitions
    • hasConstantSymbol -> c