There's a black hole at the cosmic core.

Robert Boyle said there was a relationship among Pressure and Volume, but it's inverse - if you lower the Pressure you increase the Volume, and increased Volume is Expansion, is it not?Another thing, no one can see beyond the Observable Universe (OU). What's important about the OU is that the expansion is accelerating.That said, there are only two (2) kinds of expansion, the first kind (1) Accelerates and then slows down, and the second kind (2) which Starts slowly and then accelerates.The first kind (1) is Outward, an explosion, or popping seed-case, solar wind, etc. (An explosion starts by accelerating, hope you can see that)
The second kind (2) is Inward. All Inward expansions start slowly. Now I know you've never heard of an Inward Expansion, but let me
give you one example - air approaching the nozzle of a Central-Vac will start slowly and then accelerate toward the nozzle, losing pressure and expanding into the nozzle.
Note:- a) the slow start b) the accelerating expansion and c) the Inward Direction. I know ten (10) of these accelerating expansions, all of them Inward. Try thinking of one (they are fairly common). (just not your backward Universe). Well, here goes...

Going by the title you gave your proposed thread, you somehow managed to be off-topic in your own thread proposal.If you really want to discuss the possibility of a black hole at the center of the universe then you probably need to talk about two things:

• Why you're discarding the Copernican principle and believe the universe has a center.
• The evidence for a "black hole at the cosmic core."

I suggest you discard this thread proposal and start over.