Due to mathematics, blackhole cannot exist without white holes. We know for certain that blackhole exist. Therefore, our math also states that a white hole must exist. It breaks thermodynamics, I know, however it is mathematically sound. Like how .999.....= 1. It is rather simple to prove that one. I'll let you research it if you're curious. Also, what are your opinions on the name Milk-Dromeda? Any other name you'd suggest for the galaxy after the collision with Andromeda? Say, Andro-Way?