MOND, MONG, MORG as alternatives to dark matter and dark energy, and consequences for cosmic structures

In view of the negative results from various dark matter detection experiments, we propose alternate models by postulating a minimal field strength (minimal curvature) and also a minimal acceleration. These postulates lead to modified Newtonian dynamics, modified Newtonian gravity, and modified relativistic gravity. Through these postulates, we show that the observed flat rotation curves of galaxies can be accounted for. This can also set constraints on the size of large scale structures such as galaxies and clusters, which are consistent with observations. This minimum curvature in general relativity, and consequently the modification of the Hilbert action leads naturally to a term equivalent to cosmological constant. This model thus neatly ties up, with these two postulates: the observed flat rotation curves and the accelerated expansion of the universe.