Cosmology, Black Holes and Shock Waves beyond the Hubble Length

We construct exact, entropy satisfying shock wave solutions of the Einstein equations for a perfect fluid which extend the Oppeheimer-Snyder (OS) model to the case of non-zero pressure, inside the Black Hole. These solutions put forth a new Cosmological Model in which the expanding Friedmann-Robertson-Walker (FRW) universe emerges from the Big Bang with a shock wave at the leading edge of the expansion, analogous to a classical shock wave explosion. This explosion is large enough to account for the enormous scale on which the galaxies and the background radiation appear uniform. In these models, the shock wave must lie beyond one Hubble length from the FRW center, this threshhold being the boundary across which the bounded mass lies inside its own Schwarzshild radius, 2M/r > 1, and in this sense the shock wave solution evolves inside a Black Hole. The entropy condition, which breaks the time symmetry by selecting the explosion over the implosion, also implies that the shock wave must weaken until it eventually settles down to a zero pressure OS interface, bounding a finite total mass, that emerges from the White Hole event horizon of an ambient Schwarzschild spacetime. However, unlike shock matching outside a Black Hole, the equation of state p = c 2 3 ρ, the equation of state at the earliest stage of Big Bang physics, is distinguished at the instant of the Big Bang—for this equation of state alone, the shock wave emerges from the Big Bang at a finite nonzero speed, the speed of light, decelerating to a subluminous wave from that time onward. These shock wave solutions indicate a new cosmological model in which the Big Bang arises from a localized White Hole explosion occurring inside a matter filled universe that eventually evolves outward through the White Hole event horizon of an asymptotically flat Schwarzschild spacetime.