Black hole and Big bang.
1.
A black hole is a theoretical region of space in which the
gravitational field is so powerful that nothing can escape.
2.
Hawking Radiation theorizes that black holes do not,
in fact, absorb all matter absolutely; they give off some
return matter.
Yes, but what point are you making?
3.
Once upon a time, 20 billions of years ago, all matter
(all elementary particles and all quarks and their
girlfriends- antiparticles and antiquarks, all kinds of
waves: electromagnetic, gravitational, muons…
gluons field ….. etc.) – was assembled in a “single point”
The first particles would have come into existence only after the Big Bang event.
As a matter of interest, is there any good reason why you keep revising the time of the Big Bang back to 20bya?
The reason of this unity is gravitational force.
4.
How does this “single point” created if the matter
can escape from any strong gravitational force?
==========..
Maybe the singularity was produced by colliding branes. Maybe not. Whatever, there doesn't appear to be a viable theory suggesting that gravity was responsible for the singularity. It would have been, had a Big Crunch occurred, but I think that theory is defunct (unless it's back in favour again!). Evidently, the rate of expansion of space was sufficient to overcome the force of gravity and, if the inflation theory is correct, it was given a tremendous boost by negative gravity.
