A tachyon is a hypothetical particle that travels faster than the speed of light. It is believed that tachyons could be used to send information or objects back in time.

The grandfather paradox is a thought experiment that illustrates the problems with time travel. It asks the question: what would happen if you went back in time and killed your own grandfather before he had children?

The Novikov Self-Consistency Principle states that it is impossible to travel back in time and change the past. This is because any changes you make to the past will have already happened by the time you arrive there.

The Bootstrap Paradox states that it is possible to travel back in time and change the past, but only if you can travel back in time to a point before you were born. This is because any changes you make to the past will have already happened by the time you arrive there.

The Predestination Paradox states that it is possible to travel back in time and change the past, but only if you can travel back in time to a point where you already exist. This is because any changes you make to the past will have already happened by the time you arrive there.

The Butterfly Effect states that it is possible to travel back in time and change the past, but only if you can travel back in time to a point where you don't exist. This is because any changes you make to the past will have already happened by the time you arrive there.

A time machine is a hypothetical device that is used to travel through time.

H.G. Wells is credited with writing the first story about time travel, The Time Machine, in 1895.

A Trip to the Moon is a 1902 French short film by Georges Méliès. It is the first film to depict a journey to the moon.

Doctor Who is a British science fiction television series that has been running since 1963. It is the longest-running science fiction television series in the world.

Back to the Future is a 1985 American science fiction comedy film directed by Robert Zemeckis. It is the highest-grossing time travel film of all time.

Doctor Who is a British science fiction television series that has been running since 1963. It is the longest-running science fiction television series in the world.

Tenet is a 2020 American science fiction action film written and directed by Christopher Nolan.

Doctor Who is a British science fiction television series that has been running since 1963. It is the longest-running science fiction television series in the world.

The Time Machine is a 1895 novel by H.G. Wells. It is one of the first and most influential works of science fiction.