– A universe existing alongside our own – May contain alternate versions of people, events, and history – Part of the broader idea called the multiverse
– Originated in philosophy and science fiction – Later explored by physicists through quantum mechanics and cosmology
– Infinite Universes: Endless space creates repeated realities – Bubble Universes: Separate universes formed after the Big Bang – Many-Worlds Interpretation: Every choice creates a branching universe
– No direct evidence yet – Supported indirectly by some physics models – Highly theoretical and controversial