Theoretical Time Travel: Explaining the Possibility

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The discussion centers on the theoretical aspects of time travel as it relates to Einstein's General Relativity and the concept of Closed Timelike Curves (CTCs). CTCs suggest that time travel could be possible through curved spacetime, allowing for loops in time. The mechanics of time travel along a CTC are explored, questioning whether a traveler needs to move at specific speeds or through wormholes to access these curves. It is noted that speed is relative and cannot be defined without a reference point. The conversation acknowledges the challenges posed by causality and paradoxes like the Grandfather Paradox, while also recognizing that some theoretical physicists propose ways to overcome these issues. The forum emphasizes that discussions should remain speculative and distinct from real-world science, encouraging writers to define how their fictional worlds differ from our own.
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.
 
A map of a four-dimensional planet is three dimensional, so such can exist in our Universe. I made one and posted a video to the Internet. This is all based on William Kingdon Clifford's math from the 19th century. It works like this. A 4D planet has two perpendicular planes of rotation. The intersection of such a plane with the surface of the planet is a great circle. We can define latitude as the arctan( distance from one plane/distance from the other plane). The set of all points...

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