How is cosmology different from astronomy ?
Cosmology is one branch of astronomy, which in turn, is a branch of physics. I trained in, and obtained my PhD in physics, but now teach astronomy while researching into cosmology. Whilst observational astronomers are interested in, say, the composition of stars, or the atmosphere of planets etc., cosmologists are more interested in, for example, the origins of the Universe as a whole. To that end, cosmology tends more towards the physics of the esoteric, as it has been described. My own current research for instance is in M Theory and what may have occurred before the Big Bang. At that point, I suppose, philosophy may creep in, but that depends upon the individual. Cosmology embraces not only the vastness of the Universe, but also the very smallest constituents such as those postulated by quantum theory or string theory. This does sometimes impinge on the work of particle physicists, but we do share a sort of common educational ancestry.
