Redefining Reality - The Intellectual Implications of Modern Science

Many scientists preferred the idea of constant expansion to
Gamow and Alpher’s theory. But what, then, is causing the
expansion seen by Hubble, and why do we see galaxies? Where
do they come from? Why don’t they all die out? If the universe is
getting larger, then the energy density—the amount of stuff in any
region—is getting smaller; this should mean that the universe is
dying. But that isn’t what we see when we look at the night sky.
Any theory that would preserve a static universe while allowing
for expansion would have to account for the apparent continuity of
energy density in the universe.
Two astronomers, Thomas Gold and Hermann Bondi, posited
that perhaps the expansion allowed the universe to create itself
by allowing for the spontaneous creation of bits of mass and
energy. But this seemed to contradict one of the fundamental
principles underlying the paradigm of modern physics: Energy is
neither created nor destroyed. Where would this energy and mass
magically come from?
Another astronomer, Fred Hoyle, argued that we should think
of the Einsteinian static picture in terms of the conservation
of energy density. Yes, the universe is expanding, but as it
expands, there must always be the same amount of stuff per
energy. When the universal expansion drops the average amount
concentrates its energy and increases the mass and energy of
the region.
If this were true, then we would have the conservation of energy
and the conservation of energy density. This view was called the
because it proposed that the universe was
always in a constant state with respect to how much stuff there is
per unit volume.
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