Question C.II: MOND works far too well !

Summary:

First try: Using only Solar System constraints, Newton and then Einstein developed the universal theory of gravitation. This Theory of General Relativity (GR) is then applied to model the universe. In order for it to fit the observational cosmological constraints, inflation, dark matter and dark energy need to be postulated to exist. Tests on scales of 10Mpc and less show this top-down modelling to fail despite major fine-tuning attempts.


Second try: Using Solar System and galactic constraints Milgrom and then Bekenstein developed a new theory of gravitation. This MOND and TeVeS approach is now being applied to model the universe. Cold dark matter is not needed, but applications to large-scale structure need to be developed. Tests on scales of 10Mpc and less show this bottom-up modelling to be successful without fine-tuning.


In general it follows that the need for dark matter and perhaps for the other postulates depends on the gravitational theory being used. Since we do not yet understand gravitation it furthermore follows that these postulates probably only express our lack of understanding of cosmological physics.


Indeed, ...