All Questions
13
questions
2
votes
1
answer
185
views
No inconsistencies due to closed timelike curves in General Relativity
Is there anything wrong with the following argument ruling out inconsistencies with closed timelike curves?
Math
A solution in the context of General Relativity is a pseudo-Riemannian manifold $(M, g)$...
- 917
0
votes
2
answers
88
views
Possibility of having a spacetime trajectory that cuts the $t=$constant at more than one point
Can we have a spacetime trajectory like the blue curve (shown in the figure) inside the lightcone such that the trajectory cuts a $t={\rm constant}$ line at more than one point (three points in the ...
- 11.8k
1
vote
1
answer
112
views
Why do wormholes necessarily alter time? Why don't they just make two places causally linked?
I've heard many-an-explanation of wormholes. From as a kid with the hole punch through paper, to the sci-fi something something magic, to popular YouTube science channels talking about how it could ...
- 111
0
votes
1
answer
150
views
How does going faster than light cause going backward in time? [duplicate]
I have read in many places that some virtual particles can "travel faster than light (1)" and thereby "go backwards in time (2)".
My question is about the connection between these two. I have always ...
- 171
1
vote
3
answers
2k
views
Can a telescope look into the future?
If a telescope can see the past, can it look into the opposite direction and see the future?
I suppose I am trying to put time into a single line. (timeline) with a beginning and end, and we are in ...
- 776
2
votes
1
answer
9k
views
How can I send a message to myself in the past? [duplicate]
It is easy to send a message to myself in the future: I can put a letter in the post and will receive it tomorrow.
Can you think about a way to send a message to myself in the past; it does not need ...
- 23
4
votes
1
answer
577
views
What is the latest science on closed timelike curves? [closed]
In Scientific American (Sept 2014), Lee Billings writes:
Lloyd, though, readily admits the speculative nature of CTCs. “I have no idea which model is really right. Probably both of them are wrong,” ...
- 383
0
votes
1
answer
244
views
Time Travel possibility and Paradoxes of The Past [duplicate]
can one travel back in time and if not so, what laws prevent time travel to the past. this is quite a challenge to understand.
- 93
1
vote
3
answers
10k
views
How can the past, the present and the future coexist at the same time? [closed]
We all heard it many times, the theory of Time suggest it is parallel rather than being linear. This leaves the door opened for alternate realities and well, immortality.
However, even after reading ...
- 43
0
votes
1
answer
116
views
Time relativity / paradox [duplicate]
After watching the movie Interstellar, the theory of time relativity / paradox really mind-boggles me. If it is true that gravity controls everything even to the extent of time, then it might as well ...
9
votes
3
answers
4k
views
Time travel outside of light cone without causality violation
If one is able to travel into the past but at a spatial distance that puts him outside of his own past light cone would this be considered a causality violating trip? Looking at a Minkoski diagram, it ...
- 181
3
votes
1
answer
678
views
Superluminal travel without time travel
Can superluminal travel or communication be possible without leading to the possibility of closed timelike curves (CTCs) and causality violations?
I have seen conflicting opinions regarding this ...
- 1,398
9
votes
4
answers
2k
views
Why should one expect closed timelike curves to be impossible in quantum gravity?
From the Wikipedia article, it seems that physicists tend to view closed timelike curves as an undesirable attribute of a solution to the Einstein Field Equations. Hawking formulated the Chronology ...
- 4,504