How the Big Bang Ends up Inside a Black Hole
  The standard model of cosmology assumes that our Universe began 14 Gyrs
(billion years) ago from a singular Big Bang creation. This can explain a vast
range of different astrophysical data from a handful of free cosmological
parameters. However, we have no direct evidence or fundamental understanding of
some key assumptions: Inflation, Dark Matter and Dark Energy. Here we review
the idea that cosmic expansion originates instead from gravitational collapse
and bounce. The collapse generates a Black Hole (BH) of mass $ M \simeq 5
\times 10^{22} M_{\odot}$ that formed 25~Gyrs ago. As there is no pressure
support, the cold collapse can continue inside in free fall until it reaches
atomic nuclear saturation (GeV), when is halted by Quantum Mechanics, as two
particles cannot occupy the same quantum state. The collapse then bounces like
a core-collapse supernovae, producing the Big Bang expansion. Cosmic
acceleration results from the BH event horizon. During collapse, perturbations
exit the horizon to re-enter during expansion, giving rise to the observed
universe without the need for Inflation or Dark Energy. Using Ockham's razor,
this makes the BH Universe (BHU) model more compelling than the standard
singular Big Bang creation.
