  We construct the simplest solution of the Einstein equations that
incorporates a shock-wave into a standard Friedmann-Robertson-Walker metric
whose equation of state accounts for the Hubble constant and the microwave
background radiation temperature. This produces a new solution of the Einstein
equations from which we are able to derive estimates for the shock position at
present time. We show that the distance from the shock-wave to the center of
the explosion at present time is comparable to the Hubble distance. We are
motivated by the idea that the expansion of the universe as measured by the
Hubble constant might be accounted for by an event more similar to a classical
explosion than by the well-accepted scenario of the Big Bang.
