# Theoretical Time Travel: Explaining the Possibility

• novella
In summary, the author is asking how time travel is possible in a world which is similar to our own, but different in some ways.
novella
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.

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.

Thank you.

## 1. What is theoretical time travel?

Theoretical time travel is the concept of traveling through time using scientific theories and principles, rather than through physical means. It involves exploring the possibility of manipulating time and space to travel to different points in the past or future.

## 2. Is time travel possible?

At this point in time, time travel is only a theoretical concept and has not been proven to be possible. However, some scientists believe that it may be possible in the future as our understanding of physics and technology continues to advance.

## 3. How would time travel work?

The exact mechanism of time travel is still unknown, but it is believed that it would involve bending the fabric of space-time through the use of advanced technology or through the manipulation of gravitational forces.

## 4. What are some potential issues with time travel?

One major issue with time travel is the concept of paradoxes, such as the grandfather paradox where a person travels back in time and accidentally prevents their own existence. Other potential issues include altering the course of history and disrupting the space-time continuum.

## 5. Are there any real-life applications for time travel?

Currently, there are no known practical applications for time travel. However, some scientists believe that the study of time travel could lead to a better understanding of the universe and potentially open up new avenues for space exploration.

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