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:

  1. It was the matter engulfed by a Black hole.
  2. 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?

  • $\begingroup$ I think a black hole can only become asymptotically close to equilibrium, not ever reach it, due to the expansion of the universe constantly lowering the temperature of the background radiation. That would still mean a time reversed black hole is still a white hole. That said, we have no evidence that white holes exist at all. $\endgroup$
    – Asher
    May 18, 2017 at 7:25
  • $\begingroup$ This is rather unclear. It seems to contain a quote from Wikipedia, but I can't find the original. Is it your translation of a non-English Wikipedia? I don't understand how you deduce that a white hole must be inside, or behind a black hole. I don't understand why you think a white hole would exist before the big bang. In practical terms, white holes don't exist, just as negative mass matter doesn't exist. $\endgroup$
    – James K
    May 18, 2017 at 19:26

1 Answer 1


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).

  • $\begingroup$ How quack of an idea is it that the big bang is really the outpouring via a white hole (or time-reversed black hole)? $\endgroup$
    – user15317
    May 20, 2017 at 9:31
  • 1
    $\begingroup$ @mikey You may enjoy reading about Lee Smolin's theory of cosmological natural selection en.wikipedia.org/wiki/Lee_Smolin#Fecund_universes This theory has a few problems but it's still a fascinating idea IMHO. $\endgroup$
    – PM 2Ring
    May 22, 2017 at 8:01

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