Questions tagged [time-travel]

For use on questions regarding travel forwards or backwards (or both!) in time. This tag should be used in conjunction with the universe it is found in. Can also be used to signify that the question contains time travel when asking in relation to an identification question: [story-identification], [episode-identification], [character-identification] and [object-identification].

Time travel refers to the ability to move through time in a manner which does not respect the normal, sequential ordering of events. Depending on the circumstances surrounding this ability, one may be moving from one temporal event to another wilfully, randomly, or under the influence of an outside agent or being. Time travel is a frequent feature of science fiction. For example:

  • The protagonist of H.G. Wells' The Time Machine builds a machine that allows him to travel backwards or forwards in time at will to precise years
  • In Slaughterhouse Five (K. Vonnegut, 1969), army veteran and Dresden firebombing survivor Billy Pilgrim moves through time against his will after an alien abduction
  • In the Star Trek universe, starships can travel to the past by executing a "slingshot" maneuver around a star at maximum warp, subject to very delicate calculations (see, for instance, Star Trek IV: The Voyage Home)
  • Specifically in the TV series Star Trek: Voyager and Star Trek: Enterprise, the future of Starfleet is depicted as being heavily involved with time travel and the policing of timelines
  • Superman uses his ability to fly at great speed around the Earth to reverse time and change recent events in Superman (1978)
  • In Primer (2004), the protagonists build a device that allows them to repeatedly travel several hours back in time (with eventual dire consequences)

Use this tag for questions concerning time travel and its effects, as depicted in works of science fiction.

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What are the ideas on time-travel so far in Science Fiction?

There are many SF-stories about time-travel. But with time-travel come the possibility for a paradox. As far as I can see, there are different solutions from different fictional works. Maybe some author even uses a paradox as part of the story. Can…
Mnementh
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What paradox is this scenario?

I've been thinking about various time-travel related paradoxes, and have wondered what the name of the paradox is where something doesn't have a cause. Take the following example: Let's say there is a piece of paper with some informaton on it. Bob…
joshhendo
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Are there stories where people have conflicting memories after time travel?

I've noticed that over time there have been different rules for time travel. For example, originally the grandfather paradox was dealt with by the grandson either disappearing from the timeline or some other paradox set up. Now days, it seems more…
Tango
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How did Kate & Leopold solve their money problems without L. marrying for money as he had been expected to?

In the 2001 move Kate & Leopold, before the time travel from 1876, Leopold is being forced to marry some rich American as the family fortune is depleted. In the end he announces that he plans to marry Kate who followed him from present day. So how…
liftarn
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Has science fiction used the Many Worlds Interpretation (MWI) of Hugh Everett to address time travel?

The Many Worlds Interpretation (MWI) of quantum theory first proposed by Hugh Everett in 1957, says that everything that can happen, will, in its own separate universe. (Note that this is not the multiverse, aka the megaverse theory. Each universe…
user48960
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How could the kidnapped girl in the Sound of My Voice develop a secret handshake?

In the Sound Of My Voice, in the last scene we see Maggie does a secret handshake with the kidnapped girl, and the kidnapped girl says: How do you know my secret handshake? However, how can someone develop a secret handshake without a partner to…
DSaad
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What is the volition in TimeCrimes?

TimeCrimes (or los Cronocrimenes) is an outstanding Spanish time-travel mystery. Therein, the main character witnesses himself taking actions, and subsequently reenacts them according to his recollection of what he saw himself doing. So where…
Chris B. Behrens
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Trying to identify an episode of a 1980's Sci-Fi TV Series. Perhaps Amazing Stories, Outer Limits?

Possible Duplicate: Looking for an old SF tv short story about blue men staging the future The premise is similar to the logic used in The Langoliers, in that time is constructed, & deconstructed, but living beings are simply passing through it,…
Paul
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Are there any SciFi treatments of time travel that avoid the typical paradoxes?

Possible Duplicate: Why do time-travel stories often have the characters “returning” to the future? The possibility of time travel normally creates paradoxes. If you can travel into the past and kill your grandfather, how did you exist in the…
matt_black
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"Causal loops are unchanging and self-originating, whereas time loops are constantly resetting".. What does it mean?

Recently I've started reading about Time Travel after watching it in Harry Potter and the Prisoner of Azkaban. There is a line on this subject in the Wikipedia page on 'Causal Loop' i.e. The term "time loop" is sometimes used to refer to a causal…
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Is this the Time Travel Bootstrap Paradox? - US Banknote

Is the following example using a US Banknote a Bootstrap Paradox? In January 2015, the US Govt prints a USD 10 banknote with serial no. #123456. In February 2015, it is issued for circulation and goes to John, a time traveller. John goes back in…
kopy
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What is the appropiate way to use money in the past?

Assuming time travelling is possible and there are no fancy regulations, what would be the best way to take this time's money with me to buy things in some time/place in the past? I'm asking this because money has serial numbers and the like.
chepe263
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