Galaxies Made Of Nothing?

Ant writes: "There's an interesting article from theorists attempting to explain some of the "missing mass" in the universe now say there may be entire galaxies that are dark. The new idea, proposed by Neil Trentham of the University of Cambridge, along with colleagues Ole Moller and Enrico Ramirez-Ruizof, suggests that for every normal, star-filled galaxy, there may be 100 that contain nothing, or at least nothing that we understand."