Ask HN: Top Mysteries of the Universe?

I was looking for a list of top mysteries of the universe and didn't find a list that was objective in a sense. The kinds of things I had in mind were more physics-based rather than where are the aliens?

Some of the ones I could think of:

  - fine-structure constant
  - dark-matter
  - dark-energy (varying expansion rates)
  - where's the anti-matter
  - unification of quantum mechanics and general relativity
  - black-hole event horizon area/volume vs information content
  - entanglement

These are all things that we don't understand, but don't relate to us or living things in particular.

Some specific things are the simulation hypothesis, holographic principle, how does the universe end, is a black-hole like a universe (or an electron) etc, that don't seem to be in the same category (subjectively to me anyway).