Theoretical Time Travel: Explaining the Possibility

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Discussion Overview

The discussion centers around the theoretical aspects of time travel, particularly in the context of Einstein's General Relativity and the concept of Closed Timelike Curves (CTCs). Participants explore the mechanics of time travel, the implications of causality, and the speculative nature of time travel in fiction.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Meta-discussion

Main Points Raised

  • One participant seeks clarification on how time travel along a CTC is theoretically accomplished, questioning the need for speed or specific conditions to access a CTC.
  • Another participant asserts that traveling to the past would violate causality, suggesting a strong prohibition against such actions.
  • A different participant acknowledges the existence of theoretical physicists who have proposed ways to circumvent causality, asking for a focus on the mechanics of time travel itself.
  • CTCs are described as existing in various forms across different spacetimes, with some being localized (e.g., wormhole spacetimes) and others being more universal (e.g., Godel metric).
  • It is noted that speed cannot be defined in relativity without a reference point, implying that the conditions for time travel may not be as straightforward as they seem.
  • There is a suggestion to read Kip Thorne's "Black Holes and Time Warps" for further insight into the topic.

Areas of Agreement / Disagreement

Participants express differing views on the implications of causality in time travel, with some arguing against its feasibility while others suggest theoretical frameworks that allow for it. The discussion remains unresolved regarding the mechanics of time travel and the conditions necessary for it.

Contextual Notes

Participants highlight the speculative nature of time travel in fiction, indicating that any theories discussed must be framed within a fictional context that differs from known science.

novella
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I am writing a novel about time travel and don't quite understand the theoretical science behind it.
If I understand correctly, Einstein's General Relativity theory opened up the door for the possibility of time travel even though he dismissed the idea as impractical. Einstein proved that time and space were linked as one and called this the Space Time Continum. And this Space Time Continum is curved not straight allowing for the possibility of a closed loop being created and being referred to as a CTC or a Closed Timelike Curve.
What I would like explained is how theoretical time travel is accomplished along this CTC. Does the time traveler have to be traveling in space and at a certain speed along the CTC. Is it by pure chance that he even finds the CTC to allow for his time travel. Would he have to be traveling at the speed of light or close to this maximum universal speed. Does he have to enter a worm hole that connects two distant points along the CTC or could he just fly along the CTC and eventually lap his own lifeline winding up in his past.
If you could explain this in the simplest terms possible I would greatly appreciate it.
 
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Travelling to the past would violate causality, which I think to have understood to prohibit it quite emphatically.
 
I understand the objections like causality and things like The Grandfather Paradox but I know there are theoretical pysicists that have circumvented these prohibitions to time travel. Putting them aside for a moment, explain what I have asked: the mechanics of just getting there.
 
CTCs exist in many different forms, in many different types of spacetimes. In some spacetimes, such as the Godel metric, they exist throughout the universe. In others, such as wormhole spacetimes, they are localized, and you have to pass through the wormhole.

novella said:
Does the time traveler have to be traveling in space and at a certain speed along the CTC.
No, not in the examples above. Note that you can't even define speed in relativity unless you specify what it's relative to.

You might want to read Black Holes and Time Warps by Kip Thorne.

guywithdoubts said:
Travelling to the past would violate causality, which I think to have understood to prohibit it quite emphatically.

I think that's putting it much too strongly.
 
Welcome Novella. we have special rules for the sci-fi writing forum. your post has been moved here because it is not allowed allowed in the science forum.

In this forum, it is possible for writers to ask for help with science-fiction or fantasy stories. Since science-fiction is speculative in nature, some degree of speculation is allowed here. However:
There can be no speculation about the real world and about known science. Rather, all speculative theories must be about a world which is different (although similar) from our own. Writers must give some kind of indication in what way their world is different from our world.
Please explain how your world is different.

Thank you.
 

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