A white hole is a theoretical solution to Einstein's field equations - a region which cannot be entered at all from the outside. In a sense,therefore,they are the time-reversed opposites of black holes. The theory suggests that a black hole is connected to a white hole via a tunnel called an Einstein-Rosen bridge (wormhole). Matter falls into the black hole and is expelled via the white one. Some theorists even argue that the Big Bang itself is a white hole,gushing out matter and creating a new universe while,on the other end,invisible and unreachable,is a black hole in a totally different universe |