I was amazed when I found that the Schwarzschild radius for the mass content of the universe is almost exactly the same value than the radius we get for the observable universe.

Some think that this is just a striking coincidence, but there are two other numbers that are in a remarkable aproximation on this model:

• The density inside this black hole would be almost the same than the contribution from baryonic matter we observe in outer or intergalactic space.
• The acceleration for a particle at this radius is on the order of the MOND acceleration constant used to explain the galactic rotation anomalies.

Apart from these odd coincidences, I think that focusing our attention on the escape velocity at the Schwarzschild radius is wrong. There's nothing physically fundamental breaking up there, only that matter can not pass that event horizon as long as the black hole exists (the event horizon is a coordinate singularity, not a real one).

I think we shoud be looking to where inside black holes we would reach Planck density or Planck acceleration limits. These are much more fundamental concepts than "escape velocity" (an idea incorrectly applied to massless quanta, IMHO).

For instance, Carlo Rovelli has found that thinking in these terms (using Planck density as a limit) he is able to describe the behavior and dynamics of black holes in a very simple way, getting rid of all the paradoxes at the same time.

When I found Rovelli's paper about Planck Stars (https://arxiv.org/pdf/1401.6562.pdf), everything clicked in my mind.

I'm also investigating where do Planck limits break inside black holes, and I think that the Planck acceleration limit (that is, accelerating from 0 to light speed in one Planck time) would be reached before reaching Planck density, but in any case, both limits get broken well inside the Schwarzschild radius.

I'm in the process of compiling and understanding all these findings, hoping to write about it at some point.