Time travel is the concept of moving between different points in time in a manner analogous to moving between different points in space, either sending objects (or in some cases just information) backwards in time to some moment before the present, or sending objects forward from the present to the future without the need to experience the intervening period (at least not at the normal rate).
Although time travel has been a common plot device in fiction since the 19th century, and one-way travel into the future is arguably possible given the phenomenon of time dilation based on velocity in the theory of special relativity (exemplified by the twin paradox), as well as gravitational time dilation in the theory of general relativity, it is currently unknown whether the laws of physics would allow backwards time travel.
Any technological device, whether fictional or hypothetical, that is used to achieve time travel is commonly known as a time machine.
Some interpretations of time travel also suggest that an attempt to travel backwards in time might take one to a parallel universe whose history would begin to diverge from the traveler's original history after the moment the traveler arrived in the past.
Some theories, most notably special and general relativity, suggest that suitable geometries of spacetime, or specific types of motion in space, might allow time travel into the past and future if these geometries or motions are possible.[16] In technical papers, physicists generally avoid the commonplace language of "moving" or "traveling" through time ('movement' normally refers only to a change in spatial position as the time coordinate is varied), and instead discuss the possibility of closed timelike curves, which are worldlines that form closed loops in spacetime, allowing objects to return to their own past. There are known to be solutions to the equations of general relativity that describe spacetimes which contain closed timelike curves (such as Gödel spacetime), but the physical plausibility of these solutions is uncertain.
Relativity states that if one were to move away from the Earth at relativistic velocities and return, more time would have passed on Earth than for the traveler, so in this sense it is accepted that relativity allows "travel into the future" (according to relativity there is no single objective answer to how much time has 'really' passed between the departure and the return, but there is an objective answer to how much proper time has been experienced by both the Earth and the traveler, i.e. how much each has aged; See twin paradox). On the other hand, many in the scientific community believe that backwards time travel is highly unlikely. Any theory which would allow time travel would require that problems of causality be resolved. The classic example of a problem involving causality is the "grandfather paradox": what if one were to go back in time and kill one's own grandfather before one's father was conceived? But some scientists believe that paradoxes can be avoided, either by appealing to the Novikov self-consistency principle or to the notion of branching parallel universes.
Stephen Hawking once suggested that the absence of tourists from the future constitutes an argument against the existence of time travel—a variant of the Fermi paradox. Of course this would not prove that time travel is physically impossible, since it might be that time travel is physically possible but that it is never in fact developed (or is cautiously never used); and even if it is developed, Hawking notes elsewhere that time travel might only be possible in a region of spacetime that is warped in the correct way, and that if we cannot create such a region until the future, then time travelers would not be able to travel back before that date, so "This picture would explain why we haven't been over run by tourists from the future." Carl Sagan also once suggested the possibility that time travelers could be here, but are disguising their existence or are not recognized as time travelers.
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If you want to talk about it as far as RPGs go, there really is only one true Time Travel game where time travel has a purpose other than just to start and exit the adventure.
And that's Continuum by Aetherco, which includes extensive mechanics on Time Combat.
Unlike other time travel games (and fiction), which usually depict time travelers as either lone explorers or as an all-powerful "time police", C°ntinuum assumes that time travelers (spanners) would eventually evolve their own society, with its own laws, rules, slang, groups, art movements, and the like. Time travel would color such a civilization in the same way that any other major technology (such as television or the automobile) has changed the human race. C°ntinuum states that the core question of the game is "If you could learn to span time at will . . . what form of civilization would you be entering?"
Interesting.
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Carl Sagan also once suggested the possibility that time travelers could be here, but are disguising their existence or are not recognized as time travelers.It is true that over 500 people attended Jesus Christ's Sermon on the Mount.
All but 5 of them were Time Travelers.
I read that short story. I prefer Roadmarks, makes for a better game world.
LOTS OF TIMEY-WIMEY STUFFI'm sorry. I'm so sorry.
Plagiarism is awesome!
I've seen the future and I win!
We just happen to live in a universe where time travel is not possible.
For the universes in which time travel is possible, they shrink up into a time = 0 point*, and hence never really (get to) exist.
Carry on.
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* I know I'm using a physical metaphor by saying "point" but I don't know what to call a time-point (other than a point.) In fact, because we do not have language for this it may lend weight to the argument that traveling in time in our universe is not possible.
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We just happen to live in a universe where time travel is not possible.For the universes in which time travel is possible, they shrink up into a time = 0 point*, and hence never really (get to) exist.
Carry on.
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* I know I'm using a physical metaphor by saying "point" but I don't know what to call a time-point (other than a point.) In fact, because we do not have language for this may lend weight to the argument that traveling in time in our universe is not possible.
I disagree, I think we live in a universe where time travel is highly improbable. Almost the same thing, but not quite.
I disagree, I think we live in a universe where time travel is highly improbable. Almost the same thing, but not quite.
We just happen to live in a universe where time travel is not possible.For the universes in which time travel is possible, they shrink up into a time = 0 point*, and hence never really (get to) exist.
Carry on.
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* I know I'm using a physical metaphor by saying "point" but I don't know what to call a time-point (other than a point.) In fact, because we do not have language for this it may lend weight to the argument that traveling in time in our universe is not possible.
I'll go along with this. And add, when the dice land in a way so time travel becomes possible this is the event which causes (caused) the rebirth (birth) of *our* universe.
Apparently, god made such a roll about 13 billion years ago.
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I disagree, I think we live in a universe where time travel is highly improbable. Almost the same thing, but not quite.
We just happen to live in a universe where time travel is not possible.For the universes in which time travel is possible, they shrink up into a time = 0 point*, and hence never really (get to) exist.
Carry on.
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* I know I'm using a physical metaphor by saying "point" but I don't know what to call a time-point (other than a point.) In fact, because we do not have language for this it may lend weight to the argument that traveling in time in our universe is not possible.
I'll go along with this. And add, when the dice land in a way so time travel becomes possible this is the event which causes (caused) the rebirth (birth) of *our* universe.
Apparently, god made such a roll about 13 billion years ago.
fair enough.