Resolution 9 of the 11th CGPM (1960)

Definition of the unit of time (second)

The 11th Conférence Générale des Poids et Mesures (CGPM),

considering

  • the powers given to the Comité International des Poids et Mesures (CIPM) by the 10th CGPM to define the fundamental unit of time,
  • the decision taken by the CIPM in 1956,

ratifies the following definition:

"The second is the fraction 1/31 556 925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time."

DOI : 10.59161/CGPM1960RES9E

reference
Proceedings of the 11th CGPM (1960), 1961, p86
The reader should note that the official version of this Resolution is the French text

NOTE

This definition was abrogated in 1967 by the 13th CGPM (Resolution 1).