Sorry, I still have problems with it. You have a BB “theory” that doesn’t fit the observed facts. You also have a gravitational model that doesn’t fit the observed facts. You have two choices: either your theory and model are wrong, or there is something unobserved at play. Dark matter satisfies the latter. But it’s just plain bad science to ignore the former. Sure, the existence of dark matter resolves a lot of problems with the current theories, but if the theories are wrong – who cares.
When I take into consideration that the quantity of brown dwarfs in the galactic halos is waaaaay too small to make up the missing matter, gravitational lensing hasn’t shown evidence of anything close to the required quantity of MACHOs, and despite several ongoing multi-year efforts, researchers have failed to find one single trace of evidence of even a single WIMP, I think the theory has to be called into question.
I know it’s a weak analogy and will break down quite easily, but how about this. Let’s say you have a theory that states that mixing a certain amount of element A with a like amount of element B will produce a specified amount of compound C and give off x amount of energy. But when you actually mix those amounts, you get the predicted amount of compound C, but only .2x in energy. As with dark matter, you have two choices – either the theory needs to be re-examined or you can postulate that the “missing” energy is really there, but somehow undetectable. Good science would be to say, “Let’s have a look at the theory” AND, “Let’s do some further examination of our experimental results to see if we can find that missing energy.” It’s bad science to say, “Well, we got the predicted amount of C, so our theory must be correct; the missing energy must be there in some unobservable form.”
Like I said before, the theory might be absolutely correct, but at this point, I would hardly say that it meets your posted definition of a “theory”. Any theory of cosmological origin, gravitation, and what have you which requires that we assume the existence of anywhere from 80 to 99+ percent of the matter required to make it function, doesn’t seem like it meets the requirements of a good theory. At least to me (A little disclaimer that makes what I said completely unassailable ).
