That's the problem, some theories say that there is a strange matter in space going everywhere, and if that matter touches (an example) a star it will become a strange star, it will not function properly, like the star will not have much gravity or it won't produce heat but coldness, the same thing can happen to a black hole, it won't start inhaling but will start exhaling and turn white, ANOTHER theory is that the dark matter can go to a star, giving it soo much energy that it cannot handle it and when it explodes instead of white dwarf, a white hole can occur, LAST theory is that there is a Matter called (idk it's exact name) opposite or mirror matter, when entering a black hole, It will change it to a white hole and staet ejecting energy and light...etc
