"Cosmologists have long assumed that the overall expansion of the universe is not affected by the properties of small regions within it, since these properties should average out on the largest scales.
But in any given region of space, the force of gravity between bits of matter acts as a brake on expansion. This means that expansion should slow down quickly in regions with lots of matter, while continuing without much change in mostly empty regions.

It is this difference in the expansion rate between different regions that could produce the illusion of dark energy, Rasanen says. Strangely enough, even though the expansion rate decreases or stays about the same in every region, the average rate of expansion for the universe as a whole can increase.

This is because over time, denser regions suck even more matter into them by the force of gravity, which further empties the less dense regions. This process has led to the condensation of matter into galaxies and clusters of galaxies, with ever larger voids in between."

As a regular contributor to the Master BS collection here, I must protest this effort to destabilize the grip of dark matter on our world-views. Dark matter is a priceless twist, a gem among concepts for those seeking touchstones from which to generate quality bull.

But even BS, sooner or later, must yield to the firm forward march of science. I am sure they'll come up with something, like the chicken-soup theory of particle creation or soemthing, to take the place of dark matter as a fount of ridicule.


A