  Self-similar solutions to converging (implosions) and diverging (explosions)
shocks have been studied before, in planar, cylindrical or spherical symmetry.
Here we offer a unified treatment of these apparently disconnected problems .
We study the flow of an ideal gas with adiabatic index $\gamma$ with initial
density $\rho\sim r^{-\omega}$, containing a strong shock wave. We characterize
the self-similar solutions in the entirety of the parameter space
$\gamma,\omega$, and draw the connections between the different geometries. We
find that the so-called "gap" in diverging shocks does not exist in planar
geometry, and that only type II self-similar solutions are valid in converging
shocks. We also find that in some cases, a converging shock might not create a
reflected shock after its convergence. Finally, we derive analytical
approximations for the similarity exponent in the entirety of parameter space.
