The time-travel tag has no wiki summary.
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Why is it theoretically impossible to travel back through time? [duplicate]
I know scientist have basically proved the fact that time travel to the future is possible, but persay if on wanted to travel back 30 years, why exactly would this be rendered impossible if we can go ...
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Problem with going back in the past [closed]
If I bought a time machine, the went back in time at the moment I bought the time machine and then didn't buy it, what would happen ?
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Strings and QFT: particles moving backward in time?
New question: In string theory and QFT, do particles travel back in time? Not related to antimatter: Do they travel back and forth in time in reality or are these just interpretations of mathematical ...
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It's time, but not as we know it [closed]
What time is it?
My watch has stopped...
I am inside a photon bubble and watches do not work here.
What does this mean? This post does not meet our quality standards.
What is a quality standard?
What ...
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Possibility of Time Travel? [duplicate]
Is time travel still considered as a possibility? What does the newer theories like string theory, M theory, etc. say about it.
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What happened in Philadelphia Experiment(1943 October 28)? [closed]
The Philadelphia Experiment was an alleged naval military experiment reported to have been carried out at the Philadelphia Naval Shipyard in Philadelphia, Pennsylvania, USA sometime around October 28, ...
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Wormholes and the illusion of time?
I was watching a video on Youtube by Brian Greene, "the illusion of time."http://www.youtube.com/watch?v=j-u1aaltiq4
In that video, he introduces to me the idea of a "brane," or a slice of the ...
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1answer
131 views
Faster than the speed of light and future travel [closed]
I had read somewhere that if a person attains twice the speed of light, he can actually reach the future.
But since the world belongs to one time and space, how will it change for one particular ...
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2answers
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Time travel in the past
The past weeks I watched some episodes from "Through the Wormhole" with Morgan Freeman.
When talking about traveling back in time, they said you can only travel back up to the date when the first ...
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3answers
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How does faster than light travel violate causality?
Let's say I have two planets that are one hundred thousand lightyears away from each other. I and my immortal friend on the other planet want to communicate, with a strong laser and a tachyon ...
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1answer
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Grandfather Paradox [closed]
This question related to the Grandfather Paradox.
Assume that time travel to the past is a reality. What experiment/test could the time traveler perform in order to determine if he is in his own ...
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2answers
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If airplanes' highest speed depends directly on the air it is moving through and not the ground,
If airplanes' highest speed depends directly on the air it is moving through and not the ground, does it mean we can build a time machine if only the air moves near the speed of light?
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How we can calculate time as per Sun's position rather using country clock. [closed]
Having a formula to calculate time as per Sun Position should show some minor difference of time within cities at a difference of few 100 miles.
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1answer
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Is this closed time-like curve in a Godel universe a “circle”?
Would the observer moving along the circle in this Godel space-time diagram feel fictitious forces as though he is accelerating along a circular path or would he simply arrive at an earlier point in ...
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2answers
374 views
Does Stephen Hawking not believe in Negative movement? [duplicate]
Possible Duplicate:
Is it possible to go back in time?
Is time travel possible?
According to Stephen Hawking, time travel to the future is not only possible but proven, however time ...
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1answer
99 views
Does time travel leave a mark? [closed]
From what I learnt at university, and a few things i pick up time travel might be theoretically possible. Maybe.
Hypothetically, if for instance, a futuristic robot were to suddenly (and ...
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4answers
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Messing with the past: Endless loop, or alternate timelines? [closed]
Let's take the following scenario:
A person finds a time machine. He uses it to travel to the past, and
kills his grandparents. Now because of this, his parents are never
born, they do not ...
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1answer
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Can project LISA will bring us closer to time travel? [closed]
After looking at the current discovery of Higgs Boson and the next long term plans of NASA and ESA(European Space Agency), I can't stop myself asking about the possibilities in near future.
According ...
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Energy balance of closed timelike curves in Gödel's universe
I recently read Palle Yourgrau's book "A World Without Time" about Gödel's contribution to the nature of time in general relativity.
Gödel published his discovery of closed timelike curves in 1949. ...
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1answer
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If the universe is infinite, shouldn't I already have been contacted by a time and space travelling doppelgänger?
If the universe is infinite, by virtue of chance it means that every possible configuration of matter must exist somewhere (according to this documentary).
Therefore, if we accept that the universe ...
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2answers
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Why is the probability that Kip could go back and kill his grandfather $10^{-10^{60}}$?
In The Universe In A Nutshell, page 153, Hawking says that
The probability that Kip could go back and kill his grandfather is $10^{-10^{60}}$.
How do we get this result?
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1answer
350 views
How is traveling back in time possible in theory according to some scientists? [duplicate]
Possible Duplicate:
Is it possible to go back in time?
Is time travel possible?
I get the idea of traveling to the future and it makes perfect sense as we'd be somehow trapped in a ...
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1answer
110 views
Can we develop in the future a technology that can send a message to the past? [duplicate]
Possible Duplicate:
Is it possible to go back in time?
I believe that everything is possible in this world.
If that can be done then why aren't we receiving any message from the future.
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3answers
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How does Time traveling work in practice?
There are multiple theories about time traveling. One is "proven": The time slows down according to your speed. The satellites in space are traveling faster than us, thus their clocks slows down a ...
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1answer
253 views
Time travel to future [duplicate]
Possible Duplicate:
Is time travel possible?
Is time travel possible? According to my friend, it is possible to go to the future but not the past.
In Physics, particles move faster than ...
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1answer
334 views
Time traveling and Time dilation within a multiplayer videogame [closed]
First thing first, I'm looking to implement this within a multiplayer videogame as a "special" skill or powerup, but, I'm willing to build it upon a physics based explanation/theory.
The question may ...
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how could I exist where I did not exist in the past?
If I was able to go back in time via Machine or whatever, would traveling back in time not create a paradox?
I was not there, so how could I exist where I did not exist in the passed?
i would have ...
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2answers
366 views
Does superluminal travel imply travelling back in time?
Is this statement true?
You can not travel back in time. If I travel fast enough the clock will start to go backwards, but that does not mean I am traveling back in time. It would only mean that ...
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1answer
146 views
If an apple that is rotten transports back in time will it become fresh again? [closed]
I was wondering about organics that traveling back in time. for example. I'm standing on main street where there is a an apple tree about 30 years old. I pick a rotten apple from it, I go back in time ...
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2answers
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Is travel to the distant future possible without massive energy expenditure?
Well-known physics establishes that, compared to some reference frame (I'll denote as "stationary" here), one can do several things to start at rest, end at rest, and experience less time than objects ...
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4answers
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Is time travel possible? [duplicate]
Time travel -- often featured in movies, books, or facetiously in conversation. There are also theories treating time as simply another dimension, which to the layperson might imply forward and ...
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1answer
389 views
Can the Universe create itself?--Is Gott's Use of CTC in Planck time or less valid?
My question is the title of a 1991 paper by Richard Gott and Li-Xin Li:
http://arxiv.org/abs/astro-ph/9712344
and is also a subject of his popular book, "Time Travel in Einstein's Universe"
Ultimately ...
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How are we going to measure the speed of time machine? [closed]
I have built two time machines (finally) based on two different technologies. ;)
I want to race them and see which one takes me from 12/12/1212 to 11/11/1111 (dd/mm/yyyy) first.
How can I do this?
...
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2answers
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What is time teleportation?
I read this article about time teleportation.
Can someone explain the concept better?
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3answers
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Wormholes & Time Machines - for *experts* in GR/maths
EDIT: Further clarification in the context of answers/comments received to 20 Jan has been appended
EDIT: 21 Jan - Response to the Lubos Expansion appended [in progress, not yet complete]
EDIT: 23 ...
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Time travel and nuclear decay
Reading a previous closed question an interesting variation has come to my mind.
Suppose that time travel to the past was possible:
I wait for an atom to decay and measure the time, $t_{1a}$
I ...
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0answers
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Time-travel and random events [closed]
I have a noob question about possible effects of time-travel, supposing it's physically possible, relatively to random and pseudo-random events.
Suppose the human race builds a time-travel machine ...
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6answers
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Is time travel possible? Is it possible to go back in time?
I read somewhere that according to relativity, black holes and other space related stuff it is possible to jump into past.
Is it possible for anything to go back in time either continuously or by ...
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What are some scenarios where FTL information transfer would violate causality?
I've always heard people saying, "Faster than light information transfer can't happen because it would violate causality! Effects can precede their causes!"
However, I'm trying to think of a ...
