What is Time travel: Definition and 344 Discussions

Time travel is the concept of movement between certain points in time, analogous to movement between different points in space by an object or a person, typically with the use of a hypothetical device known as a time machine. Time travel is a widely recognized concept in philosophy and fiction, particularly science fiction. The idea of a time machine was popularized by H. G. Wells' 1895 novel The Time Machine.It is uncertain if time travel to the past is physically possible. Forward time travel, outside the usual sense of the perception of time, is an extensively observed phenomenon and well-understood within the framework of special relativity and general relativity. However, making one body advance or delay more than a few milliseconds compared to another body is not feasible with current technology. As for backward time travel, it is possible to find solutions in general relativity that allow for it, such as a rotating black hole. Traveling to an arbitrary point in spacetime has very limited support in theoretical physics, and is usually connected only with quantum mechanics or wormholes.

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  1. G

    Is time travel to the future easier than the past?

    So, I've been learning about quantum mechanics as of late. If I understand correctly, there would be a large amount of energy required to "turn back the clock" on all particles throughout Earth (assume that I don't change the position of satellites or the stars) in order to go back in time...
  2. A

    Time travel into the past a possibility now?

    Hi, I don't know if I am in the right sub forum or if this topic has been discussed but I'll ask anyway. so I don't think travel into the future beyond what hasn't happened yet is possible and believe it or not, it sounds more possible to me to travel into the past since the past already...
  3. sheldonrocks97

    Exploring the Possibilities of Time Travel: Fact or Fiction?

    I was just thinking about how cool it could be to time travel, but I don't know if it's technically possible. The only Physics class I took was a first semester calculus based physics class so I don't know if they ever talk about time travel in other physics classes. I don't know if this is a...
  4. Borek

    An interesting take on (the lack of) time travel ;)

    http://arxiv.org/pdf/1312.7128v1.pdf
  5. G

    Time travel stories without paradoxes

    Hi, I'm looking for time travel stories (preferably movies) without paradoxes (grandfather paradox and similar). Also, I'm not looking for stories that try to explain changes in the past with the creation of alternate timelines. I'm talking about stories where people travel into the past and...
  6. S

    What are good time travel theories to use for Science Fiction?

    Hello! Sorry, I'm not not exactly sure if this post is in the right thread. But I would just like to ask what time travel theory is appropriate, and hopefully much easier to use, for science fiction? I am planning to write a semi sci-fi short story, and it involves using time travel: to the...
  7. cyberdiver

    How exactly does FTL travel cause reverse time travel?

    So I look at the Minowski diagrams, and I can understand that moving on the y means moving in time, and moving on the x means moving in space, but drawing some diagrams of my own, I find it impossible to see why it would imply FTL travel. All objects travel either directly on the x...
  8. G

    Is Back to the Future the Clearest Explanation of Time Travel in Film?

    Doc Brown's explanation of time travel on the blackboard, in BTTF2, the best explanation of time travel I have seen in any movie.
  9. T

    Is mind communication the key to preventing disaster in time travel?

    I am currently in the process of re-writing an episode for a Science Fiction television series. Currently the main character a 280 year old human scientist travels back in time to stop catastrophic events set in motion. I would like to stay away from the actual time travel of a human being. So I...
  10. S

    Time travel + conservation laws

    Doesn't traditional time travel violate conservation laws? If I could in effect materialize in the past, then the universe, being an isolated system would have suddenly gained matter/energy out of nowhere! Also, the atoms that make up my body would then be in two places at once since they...
  11. D

    Exploring the Possibility of Time Travel with Closed Timelike Curves

    Hey guys, Why you think time travel will be or won't be possible either now or in the future?
  12. C

    Faster than speed of light = time travel ?

    This is my first post so let me know if I'm posting this in the wrong section. I read somewhere that if we are ever able to travel faster than the speed of light that fact would automatically enable us to travel back in time. I don't see how those two things are connected. Even if we travel...
  13. V

    Time Travel Paradox Ideas - Except Grandfather

    Hey guyies, can i get some really interesting and crazy paradoxes, except the grandfather one, thank you
  14. phys-if

    Time Travel, Space Travel, Speed The Earths Movement, Speed Of Light

    I'm not sure if this is the right area of the forums. If it's not. Tell me which area would be better and I'll post this there. Time Travel- Would have to be space travel... and possibly faster than light If the time traveled and the time it takes to travel took less time to travel...
  15. B

    The Secrets of Time Travel to the Past: A Comprehensive Guide

    I'm looking for as much information as possible about time travel to the past and ideas for hoe to make it a reality. Thanks in advance!
  16. DiracPool

    Can Time Travel Ever Become Reality?

    My guess is that this topic has been covered somewhere at some point. However, I have not recently seen a general, more non-technical treatment of the subject, so I thought this may be the thread for it. In any case, for discussion purposes, I'm going to make the bold statement that time...
  17. N

    In essence how does time travel relate to space?

    So basically if you were on Mars, you cool look back and see yourself traveling to mars?
  18. A

    Confusion abt relation betwn time travel and speed of light

    i don't know in which section it belongs, so i am putting it here... according to various theories proposed by various researchers, time travel depends on the speed of light. as far as i have read/heard - i) anything traveling faster than the speed of light moves back in time. ii) anything...
  19. M

    Time Travel and the space-time continuum

    If someone were able to travel back in time and change an event in history which resulted in a divergent timeline from the one you came from would both timelines be part of the same space-time continuum? I suspected they could be because part of their timelines are shared and connected to...
  20. D

    Time Travel Paradox Involving Couples

    Has Anyone ever thought of this time travel paradox before? That a couple or more (some men and some women ok) went back in time via a Time Machine and started, i.e. seeded the Human race? That is the Human Race is a Perpetual Loop? What would this be called?? A feedback loop?
  21. D

    Is Our Current Existence Already Predestined by Time Travel?

    I have had this question and nobody can answer it, so I decided to REGISTER here. If time travel was possible, would a person living in the year 3000, time traveled back to year 1000 AD. Does that mean that life has already been played out? Meaning people living in the year 1000, feel as...
  22. P

    Exploring Backwards Time Travel with My 16 Y/O Son

    Hi - Physics is not something I studied in school and to be fair to myself, not doing so saved me from failing the class... Over the years, my 16 y/o son and I have watched Nova and we do some light reading on Quarks, String Theory etc. My son seems to understand things that I do not and from...
  23. S

    Can Exceeding the Speed of Light Really Mean Time Travel?

    Your opinion on"exceeding the speed of light means the ability to return to the past" I personally think this assertion is absurd, so I'm wondering why so many people(including physicists) think this is true.
  24. H

    The speed of light and time travel

    So, I'm certainly not a physicist but I think I've just about started to grasp the concept of relativity and spacetime - maybe. A little bit. Hopefully. Anyway, I've always felt the concept of time travel is ridiculous, or at least backwards time travel, and I was trying to prove this to myself...
  25. D

    Time Travel - Between two Kerr metric black holes w/detached event horizons

    So imagine your on Earth at a latitude of 30 to 45° N, between two rotating Kerr Metric Blackholes with detached event horizons (dual singularities) allowing you to be shielded from the crushing force of the black holes. Which way do the rotating black holes need to rotate for the past and...
  26. L

    Hawking Time Travel Experiment

    ((Wasnt sure where to post this one, but i felt this spot was good)) Okay Dr. Stephen Hawking conducted a time travel experiment in an attempt to prove that time travel will be invented one day. The basic idea was to throw a party for time travellers and announce the time and location of the...
  27. M

    Speed of light and time travel

    If it is true that when traveling close to the speed of light makes you go forward in time. Then do you go back in time (observed from the destination) as you travel to your destination close to the speed of light? And why don't particles traveling at near light speeds appear to warp time...
  28. F

    FTL and Time Travel: Exploring the Connection

    Hi 'body, ok, this is a well known issue, but i still can't find a valid explanation of why FTL implies time travel. I've read lot of explanations, and each one ends up with a nonsense telling something like "if you drive a FTL car when you'll arrive you'll see yourself opening the car door...
  29. G

    Time Travel Paradox: Can It Happen?

    I just got done watching Stephen Hawking's Into the Universe episode 2, which is about time travel. They think that time travel into the past is most likely impossible simply because of paradoxes (go back in time, and kill yourself before you went back in time). However, tiny wormholes the...
  30. S

    Would time travel to the past be possible if ?

    Would time travel to the past be possible if...? We didn't focus on reversing time itself (which is obviously impossible), but focused on accessing a past parallel universe. And creating some sort of portal to these past parallel universes, like a "quantum" wormhole (i know it sounds like...
  31. Elroch

    Rotating black holes, causality and time travel ramble

    It is well-known that associated with the Kerr solution which represents a rotating black hole, there can be a region of space-time where there are loops in space time (non simply connected paths which are navigable in principle). If this is so, it breaks causality and permits time travel in...
  32. C

    Exploring Time Travel and the Speed of Light: A Scientific Perspective

    Hi, I'm not sure if this is the right sub-forum because i know very little about this kind of stuff :/ But something has been bugging me for a while and it's probably very stupid but like i said, I know very little :) So, from what i understand if we can travel close to the speed of light we...
  33. K

    Find a curve such that time travel is minimum

    Homework Statement [PLAIN]http://vctson.com/temp/curve.jpeg Find the curve y = f(x) so that the ball travels from A to B in minimum time? Thanks!
  34. S

    Proof of time travel from future to past

    Today, October 6th 2011 I received my first official reminder about the electoral register form I obviously didn't complete on 15 October 2011 from the Registrar. He further wrote Well after trying unsuccessfully to apply Einsteins theory of simultainity to the concept of instantaneous...
  35. B

    If time travel is possible does it allow for violation of the no clone theorem

    If time travel is possible does it allow for violatation of the no clone theorem? thanks
  36. E

    Why do some think faster than c= time travel?

    The main, or one of the main, arguments I hear about neutrinos flying faster than light is that it would violate casualty aka. time travel. The Light Cone is supposed to be broken, in that case, and impossible things happen. But, even if neutrinos do travel faster than c - all we need to do...
  37. R

    Speed of light and time travel

    Hi I'm new and an idiot so please don't burn me, I wouldn't have come to a specialist forum if I could have found the answer in a more mainstream place. Anyway, can somebody please explain to me in layman's terms why, if one could travel faster than the speed of light, they'd go back in time...
  38. A

    Faster than light and time travel into the past.

    Hey i am new in this forum and just want to share my thoughts with you guyz at the recent finding at CERN . If the findings of CERN experiment are correct then does it means that time travel into the past is proved WRONG.? Because according to relativity theory if something moves faster...
  39. B

    Faster than light and time travel

    Why does faster than light travel or propagation mean time travel backwards to violate causality?
  40. T

    Is time travel to the past or travel to a multiverse possible?

    And how is it possible or not possible? Can you also take into consideration the new advancements in physics. thanks
  41. Arjun Ar

    Why can't we time travel in backward?

    Why can't we time travel in backward?? Consider a person traveling in space (Straight road) O <|> /\ _______________________________________________ 0 Km 12 Km He travels at 100 m/s and completes 12km in 2...
  42. T

    Time travel by going fast in a spaceship: questions

    Hi! First of all, I just want to say that I don't know much about general relativity. But my question concerns an example often found in textbooks about special relativity. On to my question. I have heard several times that one can travel forward in time (earth-time) by leaving earth...
  43. F

    Time travel not possilbe anymore?

    http://www.physorg.com/news/2011-07-hk-physicists-photons.html I thought to the future was possible, but not anymoerÉÉ
  44. S

    How does the universe handle paradoxes caused by time travel?

    Hi. This seems like the right place to discuss how the universe is built. So, answer me this: How would the universe react to Time Travel? Time Travel is (atleast to the extent of what I know) the activity which may cause most paradoxes. Paradoxes are weirdo nasty things, and the question...
  45. T

    Time Travel: What are the Theories & Factors?

    There has been much discussion of time travel, but I haven't yet found an answer to a question I have. That is, what are the specific theories or factors that allow for the possibility of time travel? The issue has been discussed and debated many times on this forum and I'm not so much...
  46. P

    What does string theory mean for time travel into the past?

    Being tremendously bored I was looking up things on the outskirts of possibility like time travel into the past on wikipedia. There I was reading about Hawking Chronology Protection Conjecture argument against such possibilities for time travel to the past as a result of the fundamental laws of...
  47. B

    The Illusion of Free Will in the Context of Time Travel and Paradoxes

    so they say we can't travel back n time because it would create a paradox. Theres a line of thought that's says it may be possible i we select the history that does not cause a paradox. However it seems to me that quantum physcics also says that all historys exsist until we collapse the wave...
  48. B

    Exploring Time Travel Particles: Beyond Tachyons

    Are there any other particles besides tachyons that time travel backwards?
  49. A

    Is Faster than Light Time Travel Possible?

    Hello, I'm a high school senior interested in studying physics in college. I was listening to a podcast by Neil deGrasse Tyson in which he stated that if one could travel faster than the speed of light, it might be possible to travel back in time. He didn't really expand on that so I was...
  50. S

    No-cloning theorem and time travel

    Does no-cloning theorem contradict with the possibility of time travelling? If i send a photon back in time from t1 to t0, then between t0 an t1, I could have two identical photons, in other words, i can use the time machine to clone my photons. Have I missed out something?
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