However, McGaugh and his colleagues argue that these predictions do not match JWST observations. Instead, the newly observed galaxies appear bright, large, and fully formed, even as scientists peer deeper into the universe’s past. This unexpected brightness directly challenges the conventional understanding of galaxy formation driven by dark matter.
Are you sure these aren’t old galaxies? Like, how do we know that we aren’t in a relatively small little bubble and there’s an infinite universe out there where there isn’t a single big bang, but instead small bangs that happen every now and then. Maybe if a black hole gets massive enough then its gravity “overflows” and causes it to vomit everything up; and all those bright, fully-formed galaxies are actually unrelated and proceeded the big bang.
We aren’t looking at those old galaxies today. Due to the speed of light and the vast distance involved we are looking at the light from those galaxies when they were very young and early in the life of the universe (that’s why we are looking there in the first place). That light is just now reaching us. We have theorized about white holes but never seen one. By looking at closer objects we already know what an old galaxy looks like. And nothing can by definition exist before the big bang. Because before the big bang there wasn’t any space for things to exist in. Nothing precedes it.