  By means of the experimental result on the present equipartition between
background microwave radiation energy and that of the interstellar magnetic
field, and by advancing a Machian relation for the magnetic field, which,
differently than in other authors' papers, is valid for the entire spanlife of
the Universe, implying that the magnetic field depends on the inverse radius of
the Universe, we obtain a general formula such that B depends on the inverse of
R . Our estimate for Planck's magnetic field is (1/1000) times the Sabbata and
Sivaram's one. It is shown that the energy densities involved in the above
problem are dependent on the inverse square of R . For radiation, this implies,
as we show, that the total entropy of the Universe is increasing with
expansion. In particular we show that R depends on the inverse square of T,
where T is the absolute temperature, and the entropy is proportional to the 3/2
power of R .
