Alternate realities, also known as parallel universes or multiverses, refer to hypothetical versions of reality that exist alongside our own. These realities may have different outcomes based on choices made or events that occurred differently. The concept is often explored in science fiction, where characters might travel between these worlds, experiencing variations of their lives. In scientific discussions, alternate realities can arise from theories in quantum mechanics, suggesting that every decision creates a branching universe. This idea is illustrated in the Many-Worlds Interpretation, which posits that all possible outcomes of quantum events actually occur in separate, coexisting realities.