Depending on the type of black hole solution considered, there are several types of white holes. In the case of the Schwarzschild black hole mentioned above, a geodesic coming out of a white hole comes from the "gravitational singularity" it contains. In the case of a black hole possessing an electric charge ψ ** Ώ ** ώ (Reissner-Nordström black hole) or an angular momentum, then the white hole happens to be the "exit door" of a black hole existing in another universe. Such a black hole - white hole configuration is called a wormhole. In both cases, however, it is not possible to reach the region "in" the white hole, so the behavior of it - and, in particular, what may come out of it - is completely impossible to predict. In this sense, a white hole is a configuration according to which the evolution of the universe cannot be predicted, because it is not deterministic. A "bare singularity" is another example of a non-deterministic configuration, but does not have the status of a white hole, however, because there is no region inaccessible from a given region. In its basic conception, the Big Bang can be seen as a naked singularity in outer space, but does not correspond to a white hole.