Test #7: Galaxy evolution

If the universe originated just 10-15 billion years ago, galaxies are a recent phenomenon, and galaxy evolution would be a strong feature of the early universe. If the universe is not expanding, then presumably galaxies today are of the same character as those of 10-15 billion years ago. It is argued that, in a non-expanding universe, the radio galaxy 3C 65 at a redshift of 1.2 would be larger and fainter than any known galaxy in the local universe at the present epoch¹¹, which seemingly implies the need for evolutionary effects. However, as already noted, in many static universe cosmologies, redshift is not a distance indicator for quasars and most types of radio galaxies. So inferences about the true size and intrinsic brightness of the radio galaxy would not be applicable. Indeed, the entire progression from quasars to ordinary galaxies, postulated in the big bang, is interpreted quite differently in static models, so that no clear distinguishing test of models appears possible using these exotic objects.

In recent years it has been popular to point to the so-called "Butcher-Oemler effect" as evidence that galaxies do evolve with time. This is an observation that faint blue galaxies are far more abundant at redshifts of 0.4 and up than they appear to be in the local universe. However, in the most recent findings it now appears that low-surface-brightness (LSB) galaxies may be the local counterpart of these faint blue distant galaxies.¹² LSB galaxies are difficult to discover locally because we tend to look right through them. But in a recent survey specially designed to detect such objects, they appeared to be as abundant as normal spiral galaxies. However, like their possible distant cousins, they are much bluer than spiral galaxies, making them good candidates to be the local counterparts of the Butcher-Oemler faint blue galaxies. If that identification is correct, this strongest remaining argument for the evolution of galaxies as a class with time would be invalidated.