Predicted by Einstein's equations but never observed, white holes are considered highly unstable, if they can form at all. One fascinating hypothesis is that the Big Bang itself was a white hole event—the explosive output of a singularity. Another idea is that a black hole in our universe could be connected to a white hole in another, forming an Einstein-Rosen bridge (a wormhole). For now, they remain a captivating "what if" of theoretical physics. #whitehole #physics #theory #cosmology #wormhol