Isn't there also observational data that disfavors MOND?
I remember it had something to do with galaxies colliding and the dark matter staying behind or something along those lines.
I remember it had something to do with galaxies colliding and the dark matter staying behind or something along those lines.
Either case seems pretty hand wavy honestly. When it comes to galaxy and universe level physics it all seems pretty weak compared to the sort of particle physics and classical physics that we can actually measure and test on Earth. It's all just a bunch of theoretical math with relatively few actual measurements to pin it all down. I don't think we're anywhere near having a solid theory of the universe so it's mostly an exercise in trying to prove which theory is the least wrong at this point, rather than which one is correct.
Some of the other crazy observations like ultradiffuse galaxies are, on recalculation, not as extreme as initially guessed, and predicated on an indirect empirical estimate of mass (number of globular clusters) with no mechanistic confirmation.