  The recent observations on the far quasars absorption lines spectra and
comparison of these lines with laboratory ones provide a framework for
explantation of these observations by considering a varying fine structure
constant, over the cosmological time-scale. Also, there seems to be an
anomalous acceleration in the Pioneer spacecraft 10/11 about $ 10^{-10} {\rm
m}/{\rm s^2}$. These matters lead Ranada to study the quantum vacuum to explain
these problems by introducing a phenomenological model for the variation of
$\alpha$. In this manuscript we want to show that this model is not a quantum
model; it is a classical model that is only in accordance with mentioned
observations by adjusting some parameters and is not based on a fundamental
physical intuition.
