Varying coupling constants and their interdependence

Since Dirac predicted in 1937 the possible variation of gravitational constant and other coupling constants from his large number hypothesis, efforts continue to determine such variation without success. Such efforts focus on the variation of one constant while assuming all others pegged to their currently measured values. We show that the variations of the speed of light c , the gravitational constant G , the Planck constant h , and the Boltzmann constant k are interrelated: G ∼ c 3 ∼ h 3 ∼ k 3 / 2 . Thus, constraining any one of the constants leads to inadvertently constraining all the others. It may not be possible to determine the variation of a constant without concurrently considering the variation of others. We discuss several astrophysical observations that have been explained recently with the concomitant variation of two or more constants. We also analyze the reported and unexplained 35 μ g decrease of 1 Kg Pt-Ir working standards over 22 years of measurements and show that they can be accounted for by allowing G , c , and h to vary as predicted, provided such mass decrease can be confirmed with a Kibble balance used for determining the Planck constant and weighing test-masses with extreme precision.