White hole

A white hole is a theoretical opposite of a black hole that would spray matter and energy outward into space instead of pulling everything inward. While black holes are cosmic vacuum cleaners that trap anything crossing their event horizon, a white hole would be a cosmic fountain, ejecting material and radiation that nothing could ever enter. Though they're mathematically possible according to Einstein's equations, white holes have never been observed and most physicists think they're unlikely to actually exist in nature.