No. One of the issues with current understanding of galaxies is that our understanding of gravity does not fit the rotation of the galaxies we are observing. To

No. One of the issues with current understanding of galaxies is that our understanding of gravity does not fit the rotation of the galaxies we are observing. To explain this, and other effects, we use dark matter. There was a theory that the reason for the discrepancy is that our understanding of gravity is wrong, and that it is in fact a calculation error on galactic scales. The problem with this is that apparently there are galaxies which seem to have very little dark matter and are much closer to expected behavior than other galaxies. So we are left with the dark matter explanation so far.