time asymmetry

Time asymmetry refers to the idea that certain processes happen in one direction of time and not the other. For example, broken glasses don’t naturally reassemble, and ice melts but doesn’t spontaneously refreeze. This shows that while the fundamental laws of physics are mostly reversible, real-world events tend to proceed in a specific direction—often called the "arrow of time." This asymmetry stems from increasing disorder or entropy in the universe, making certain processes irreversible and giving time a preferred direction from past to future.