A time machine is a hypothetical device that allows individuals to travel through time, either to the past or the future. The concept has been popularized in science fiction literature and films, where characters often explore different eras or alter historical events. The idea raises questions about the nature of time and causality. In theoretical physics, some scientists speculate about the possibility of time travel through concepts like wormholes or the theory of relativity proposed by Albert Einstein. However, no practical time machine has been created, and time travel remains a topic of debate and imagination rather than reality.