But if you think of a white hole as something that’s the opposite of a black hole, then no: white holes aren’t real. However, white holes are a cute idea so they show up a lot in sci-fi. White holes are a mathematical abstraction that necessarily exist in the infinite past. The black hole’s interior is the upper triangle, the entire universe is the right triangular region and the white hole is the lower region. Sci-fi is about the only place you’ll hear people talking about white holes.