| > Is that correct? Basically, yes. But I would add a few points: > GR is a formula that perfectly matches a dataset of local observations. More precisely, our best current model of the solar system, which uses GR as its law of gravity, matches our best current dataset of solar system observations. But similarly, our best current model of the universe, which also uses GR as its law of gravity but is a different model, matches our best current dataset of universe observations--which includes galaxy rotation curves but also includes many other observations. > they clump randomly like some non-interacting blobs/streams and do not form a general rule. This new dataset is either still too small or has no clear formula describing it at all I'm not sure what you mean here. Our dataset of universe observations is described by a "clear formula"--our best current model of the universe, which I described above. That model includes "dark matter", i.e., matter that we cannot see, but whose presence is necessary to account for the motion of things that we can see if we use GR as our law of gravity. MOND proponents criticize the above model because it includes matter that we can't see. But that's not the same as saying the above model doesn't account for observations. It does. |
That model includes "dark matter"
Yeah, I meant that if we “turn a blind eye” on dark matter in GR, then no universal formula can cover it. In the same sense that universal jet aerodynamics formulas don’t account for trees and mountains.