The similarity of our universe to a black hole
1. The universe is expanding, but, in turn, black holes can also
grow rather quickly in size due to the absorption of mass.
2. Nobody knows where the border of the Universe is - we know
only about cosmological horizon. The border of the universe has
never been seen, and can we ever get to it? The limits of the
black hole, the event horizon, no one and nothing can leave, not
even the light.
3. Another interesting point - in the center of the black hole there
is a singularity, which is a point in space-time, where the density
of matter is so high that the laws of physics that are familiar to
us no longer work in it. The same singularity is also present in
the cosmological model of the Universe - in the Big Bang Theory.
4. Among the similarities there is also spherical symmetry, in
which, if an object is inside a black hole, then wherever it looks,
it will be the same everywhere - there is only a black hole around.
In the Universe, too, at sufficiently large distances, wherever you
look, all is the same everywhere.
5. Scientists have noticed that the Schwarzschild radius for the
observable universe coincides with the radius of the black hole
event horizon. The essence of this statement is that if an object
with a certain mass is less than the Schwarzschild radius for this
mass, then it will be a black hole. For example, if you calculate
such a radius for the Earth, then, in order for the Earth to turn
into a black hole, it is necessary that this radius is slightly less
than a centimeter. The logic is that the radius of the observable
Universe and its mass are such that it should be a black hole, by
analogy with the fact that our planet was one and a half centimeters
in diameter. Our world and the black holes themselves are
described mathematically by the same Einstein equations, maybe
this is just a coincidence?
Hypothesis (https://bit.ly/3E7Y9QF). A particularly interesting
version is that each black hole contains its own universe, and they
all exist like a bubble in a bubble, and parallel worlds, possibly
very close to us. Matter from one universe is absorbed, drawn into
another, and there, in a parallel universe, it seems to them that
scientists are seeing some kind of Big Bang - the Big Rebound,
which may be the cause of the expanding universe. It turns out
that everything in the world is cyclical. One state passes into
another, and our Universe was born in the same way.