I'm not well versed in celestial mechanics, but I see a lot of "we're in a black hole" comments so far, and I'm super curious as to whether or not we know why black holes prefer a direction of spin. Can you (or anyone, really) shed light on that?
It's not that black holes prefer a direction, it's just that they have a direction at all. It's one of the very few observable properties of a black hole.
If I'm following correctly, the "we're inside a black hole" idea is a major reach, connecting at least two unrelated concepts (black holes could contain baby universes; black holes have spin). But it's a really interesting idea and not obviously wrong.
"A preferred axis in our universe, inherited by the axis of rotation of its parent black hole, might have influenced the rotation dynamics of galaxies, creating the observed clockwise-counterclockwise asymmetry,” Nikodem Poplawski