Used to be, before Copernicus, that the Ptolemaic (the P is silent) view of the universe prevailed. You know the old story, the Earth is the center of the universe and everything revolves around us. Followers of Ptolemy (the P is still silent) had devised a complicated mechanical model using epicycles to describe how the planets moved. They had been working on this model for centuries, and as time past discrepancies were discovered, and each discrepancy was answered with another epicycle. Their model was so good that when Copernicus came along the Ptolemaic model was more accurate. Problem was that Copernicus assumed the planets were following circular orbits instead of elliptical. Eventually Copernicus was proved right, but it required a fundamental shift in the way people thought about our solar system (at least among people who thought about it at all).
So Mark and I, and Halton Arp and several other people, think we have a similar situation here. The establishment has a very detailed and fairly accurate, but completely wrong theory about how the universe works. There is another view (undoubtedly correct), but it is not going to get a hearing until there is proof, and there is not going to be proof until supporters of this heresy are allowed access to the equipment they need to prove it. It's the old catch-22.
As Mark says: If you take "Dark Matter", translate it to Latin, and read it backwards it spells "epicycle".
Update September 2016 replaced missing picture.
Update February 2021 replaced dead link.