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How does a white hole form in nature if it were to exist? No knowledge of general relativity or advanced mathematics but doing a researching a physics project and need a basic explanation.

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A white hole isn't formed. This is the definition. If $t$ is cosmic time, then a white hole is black hole that existed at $t=-\infty$.

Take a look at this Penrose diagram. (Ignore the parallel universe piece.) enter image description here The corner where $r=0$ and $r=\infty$ meets is called the past timelike infinity. We see that the white hole existed at that time. For a universe that does not have a beginning (for example no Big Bang), the white hole has always existed.

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  • $\begingroup$ So basically what are the conditions which need to be satisfied which would permit a white hole coming into existance? $\endgroup$ Feb 3, 2015 at 20:16
  • $\begingroup$ The point is that they don't come into existence. The question you should is asking is, "What are the conditions that allow white holes to exist?" I don't think we know a definite answer. (At least I don't.) There are some modern theories which suggest the Big Bang is itself a white hole. $\endgroup$
    – Ryan Unger
    Feb 3, 2015 at 20:37
  • $\begingroup$ I've heard though people going on about "eternal" black holes amongst other things. What's all that about? $\endgroup$ Feb 3, 2015 at 20:50
  • $\begingroup$ An eternal black hole is a white hole. It used to be that white holes were eternal black holes, but the definition might have been broadened recently. $\endgroup$
    – Ryan Unger
    Feb 3, 2015 at 20:59
  • $\begingroup$ Another way of putting it is that a white hole can be thought of as a certain kind of initial condition. $\endgroup$ Feb 4, 2015 at 5:13

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