Does a White hole lies behind a Black hole? While reading about a White holes, I stumbled upon a question "Where does the matter emitted by a White hole come from?" There seems to be 2 possible candidates:  


It was the matter engulfed by a Black hole.  
Matter was created inside the White hole.  


My search on wiki stated that:  

According to Penrose Diagram of Schwarzschild radius, objects first leave the White hole and then may enter into a Black hole. But, due to Hawking radiation, a Black hole can achieve thermal equilibrium with gas of radiation. This equilibrium state is reversal invariant, implying that time reversal of a Black hole is again a Black hole. This means that a Black hole and a White hole are same objects.

My 2nd candidate suggests that the big-bang was a white hole. I thought of ruling this out because it requires the existence of a white hole before the big-bang.  

This forced me to draw the conclusion that a white hole must either be inside a black hole or behind it. 

Is this correct (provided that we haven't yet proven the existence of a White hole)? Where am I wrong?
No, there is probably no such thing as a white hole in real life. A white hole is basically a time-reversed version of a black hole. Just as a black hole cannot be destroyed in classical General Relativity, a white hole can never be formed in GR. So while a white hole is technically a thing that could exist, there is no way to form one unless it was there at the beginning of the universe. We don't have any reason to think white holes existed at the Big Bang, so we think they don't exist (and never will).