Evolution is also most definitely not a theory for the origin of the universe. As interesting as this question is, it is, rather, the realm of physics and cosmology. Mutations and natural selection, the mechanisms of evolution, do not have anything to do with stars and galaxies. It is true that some people, even astronomers, refer to the “evolution” of the universe, but this is meant in the general sense of change through time, not in the technical sense of the Darwinian theory. That the universe does “evolve” in this larger sense is clear from the fact that powerful telescopes such as the Hubble can actually peer into the distant past (thanks to the fact that light travels at a finite speed) and show us first hand what primordial galaxies looked like.
The origin of the universe, as the origin of life, is of course a perfectly valid scientific question, even though it is outside the realm of evolutionary biology. Currently, our best hope to understand it lies in what physicists call superstrings theory, which is a highly sophisticated (and entirely provisional) theory aiming at fusing the two major explanatory paradigms of modern physics into a unified theory. So far, macroscopic phenomena (such as the “evolution” of stars and galaxies) have been very successfully explained by Einstein’s theory of general relativity. Similarly, quantum mechanics has been astoundingly successful in explaining the behavior of matter at the very smallest, subatomic, scales.
The problem of the origin of the universe (and a few others, such as the behavior of black holes), however, lie in a realm in which microscopic phenomena directly affect macroscopic ones (since the universe likely originated with a minute particle that rapidly expanded to gigantic proportions in the so-called Big Bang). Superstrings theory is the currently most promising (albeit still rudimentary) attempt at understanding what happens under those conditions at the boundary between relativity and the quantum world. If correct, this theory may provide us with a sound scientific basis to explain the origin of the universe.