How the Big Bang End Up Inside a Black Hole

The standard model of cosmology assumes that our Universe began 14 Gyrs (billion years) ago with a hot Big Bang expansion out of nothing. It can explain a vast range of different astrophysical data from a handful of free cosmological parameters. However successful this model is, we have no direct evidence or fundamental understanding of some key assumptions: low entropy start, Inflation, Dark Matter and Dark Energy. Here we present a simpler and more physical explanation for the same observations that do not require such assumptions or new laws of Physics. It is based on the evidence that we live inside a Black Hole (BH) of mass $ M \simeq 5 \times 10^{22} M_{\odot}$, which we observed as cosmic acceleration. How did the Big Bang end up inside such a BH? We propose that 25 Gyrs ago, a very low density cloud with this mass collapsed and form a BH. The collapse continued inside until it reached neutron energy densities (GeV) over solar mass ($M_{\odot}$) causal regions that exploded, like supernovae, producing a bounce and the Big Bang expansion. During collapse, perturbations exit the horizon to re-enter during expansion, given rise to the observed universe. We review the theoretical and observational evidence for such BH Universe.