I wouldn't put dark energy, black holes and the big bang on a level with dark matter. Dark energy is just a name for what's otherwise known as cosmological con

I wouldn't put dark energy, black holes and the big bang on a level with dark matter. Dark energy is just a name for what's otherwise known as cosmological constant. Yes, some people might believe that it's unnatural for the cosmological constant to be as small as it is and others might believe that it should really follow from a proper quantum theory, so there are definitely a bunch of open questions. But that doesn't change the fact that it's there. The same thing goes for the Big Bang and black holes. We have absolutely no reason to believe they don't exist. (To the contrary, we have every reason to believe so.) Dark matter, however, is just one possible (and comparatively speculative) explanation for various experimental deviations from theoretical predictions, regarding among others the stellar velocity distribution within galaxies, gravitational lensing and structure formation.