10 Terrifying Theories About What the Universe Is Expanding Into

Einstein’s equations for general relativity are famously indifferent to the direction of time. When feeding them the concept of a black hole, a region of space where gravity has collapsed matter to infinite density, mathematicians arrive at a solution with equal validity. It is an object that, instead of pulling everything in, pushes everything out. We call this a white hole. This is a region from which matter and energy emerge continuously, and into which nothing can ever fall. For decades after this solution was first formally characterized in the nineteen sixties, the majority of physicists dismissed white holes as mere mathematical curiosities, artifacts of the equations with no physical reality.