# Are white holes made of exotic matter

I have recently watched Kurzgesagt in a Nutshell's video on Wormholes https://www.youtube.com/watch?v=9P6rdqiybaw and I have been thinking about white holes, and exotic matter.

As I understand, white holes are an exact opposite of black holes, Black Holes are condensed of positive mass, where it is so heavy that it attracts everything into it. White holes are opposite, they repel everything that goes around it and give out 'stuff'.

Hence, I am thinking if white holes have this property, would it mean it has negative mass, which is essentially exotic matter?

• the question is good, but probably the available answers will fall short Aug 14, 2018 at 13:56
• The classical solution for a black hole is given by schwarschild metric with parameter M as the mass of the central object. A negative value of this parameter results in a naked singularity. On the other hand Schwarschild solution with positive provides a white hole part that, as you say, acts like an opposite black hole (furthermore, is a time reverse image of the black hole) but still with positive mass. Ultimately, 'exotic matter' is an umbrella term for matter that does not follows the conventional assumptions for matter (and one example is negative mass), so the term is rather ambiguous. Aug 14, 2018 at 14:00
• Would the no-hair theorem not also apply to white holes so that "what's the inside made of" has no more validity than the same question about black holes ? Aug 14, 2018 at 14:05
• @lurscher Yes... I understand. I have researched for this before too. I know that white holes are not quite possible already because if there is a white hole then we would have definitely experienced it
– rcw
Aug 14, 2018 at 14:10
• what I mean is the only in the last decade we have begun to poke holes in the hidden relationships between thermodynamics and gravitation, certainly the time-reversal property of black holes has some relationship with that, but is not known the nature of that relationship Aug 14, 2018 at 14:15