Three interesting possible explanations for galactic rotation curves have been proposed: (1) the dark matter hypothesis (DM) introduces non-baryonic matter that is insensitive to all interactions except gravitation, but there has been no detection of any possible form of dark matter; (2) a modified Newtonian dynamics
(MOND) effective at all distance scales when the accelerations are less than 1.
Finally we follow another avenue and find modified Newtonian dynamics induced by the Yang's Noncommutative Spacetime algebra involving a lower and upper scale in Nature.
Finally, in 4 we study another interesting avenue for the origins of modified Newtonian dynamics based on Yang's Noncommutative Spacetime algebra involving a lower and upper scale  that has been revisited recently by us  in the context of holography and area-quantization in Cspaces (Clifford spaces); in the physics of D-branes and covariant Matrix models by  and within the context of Lie algebra stability by .
has been studied in  and its relationship to modified Newtonian dynamics and fractals by , .