  The product of two empirical constants, the dimensionless fine structure
constant and the von Klitzing constant (an electrical resistance), turns out to
be an exact dimensionless number. Then the accuracy and cosmological time
variation (if any) of these two constants are tied. Also this product defines a
natural unit of electrical resistance, the inverse of a quantum of conductance.
When the speed of light c is taken away from the fine structure constant, as
has been shown elsewhere, its constancy implies the constancy of the ratio e2/h
(the inverse of the von Klitzing constant), e the charge of the electron and h
Planck constant. This forces the charge of the electron e to be constant as
long as the action h (an angular momentum) is a true constant too. From the
constancy of the Rydberg constant the Compton wavelength, h/mc, is then a true
constant and consequently there is no expansion at the quantum mechanical
level. The momentum mc is also a true constant and then general relativity
predicts that the universe is not expanding, as shown elsewhere. The time
variation of the speed of light explains the observed Hubble red shift. And
there is a mass-boom effect. From this a coherent cosmological system of
constant units can be defined.
