Dark Matter, Dark Energy, Black Holes, mathematical fantasies, an expanding universe, and such are ad hoc patches made on the standard cosmological model. They couldn’t understand why galaxies don’t fly apart and why a galaxies rotational speed is different than what theory says they should be. So they had to create patches to satisfy their theory.
In reality there are no such things as black holes, dark matter, dark energy and escapes into mathematical fantasies. Instead of a gravity centric universe it is instead electricity centric. Electricity is thousands of times greater than gravity. Birkeland currents, electric arcs, and other explanations of the Electric Universe explain reality much better. In my humble opinion, of course. 🙂