Wormhole as a device for studying a black hole’s interior

It is shown that by using a traversable wormhole one can get information from a black hole’s interior. The change of a black hole’s geometry in the presence of a wormhole falling into it is analyzed. The causal structure and the properties of the event horizon of a Schwarzschild spacetime with a wormhole are considered. Information and energy extraction from the interior of a black hole by using a wormhole is discussed.