Ok, then how does your chemistry comment have anything to do with the motion of galaxies? Reminder: you're commenting on an article about MOND, which is a theory that stems from trying to explain the motion of galaxies.
> outside of extreme energy/mass environments, gravity is described by Newton's law of gravitation with very high precision. If you look very hard, you may notice differences on the order of 10e-MANY. But for all intents and purposes, gravity is Newtonian in 99.99999% of the universe.
I meant it in the sense that "most of the cosmos runs on Newtonian gravity, therefore we can ignore GR" is similar to "most of the visible matter in the cosmos is hydrogen/helium, so we can ignore chemistry".
The interesting part is in the 0.0000001% that isn't like the others.
Galactic dynamics is governed by gravity, which is Newtonian at those scales.