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. N

    Exploring the Possibilities of Time Travel Paradox's

    If one of the problems with time travel is the paradox's it creates, if we take the multi-worlds theory into account where there are an infinite amount of universes and hence a infinite amount of possibilities why in one universe could there not be entropy be decreasing instead of increasing and...
  2. J

    Time travel and the 2nd law of thermodynamics

    it is often stated that time travel is not forbidden by any law of physics. but doesn’t the second law of thermodynamics forbid it because going back in time would involve a decrease in entropy?
  3. M

    Motivation for time travel into the past

    Hi, Today I was sitting in the train and I wondered what the motivation for a time traveler would be if he wanted to go in the past. Say that I live in 2011 and I went back 210 million years ago to see the dinosaurs, that would be my motivation. But when I would travel back to there and...
  4. S

    Who's the Top Expert in Black Hole & Time Travel Theories?

    Hello Friends, I need to find out who is currently THE TOP expert in the US in black hole, worm hole and time travel theories. When I last checked, it might have been Kip Thorne or Stephen Hawking, but perhaps there are others who are also prominent. I would love to hear your opinions...
  5. B

    Sideways Time Travel - Could It Happen?

    This may be a bizarre idea, even idiotic idea but could you move sideways through time? I have heard that time may flow differently in various places. We experience a forward flow of time whereas some other planet in our universe could experience a reversed flow of time. However, if time is like...
  6. J

    The Conundrum of Duplicating Atoms in Time Travel

    Let’s say someone travels one year in the past to change their own lives coarse, maybe lotto numbers or something else. Doesn’t matter if time travel is possible or not, this is just a thought experiment.? The problem I see is that somehow you’ll have to duplicate the nuclei that make up your...
  7. D

    How does the concept of light cones relate to time travel?

    This is a conversational post, I am looking for others opinions on the diagram below related to time travel. If it is in the wrong room, please move it to the appropriate location. Thank you. I look forward to hearing your opinions...
  8. Ryan_m_b

    Why Does FTL Travel Lead to Time Paradoxes?

    I'm not a physics student but have always been interested. That said my knowledge is very slim. I've always wondered why traveling faster than light would lead to time travel, I've poured over websites and other forums but they tend to descend into physics that is beyond me. Here is an outline...
  9. C

    Does Einstein's Theory of Relativity Substantiate the idea of Time Travel?

    Ronald Mallett, PhD is a renowned physicists known for his proponents on the idea of time travel. Mallett uses his background in physics and mathematics to support his idea to build a time machine, using Einstein's Theory of Relativity as a basis. Do you think this is even possible? Right...
  10. Q

    The paradox, is basically a theory about time travel.

    The paradox, is basically a theory about time travel. This thread requires the assumption of making time travel possible. Supposedly, you go back in time and kill your grandfather before he gets married. How did you end up there in the first place?
  11. N

    Understanding Time Dilation and Its Implications for Time Travel

    Good Afternoon, After watching a TV program "Into the Universe" "Time Travel " I have some doubts left. I know Time Dilation has been proven by experiments (Atomic clocks on jet plains) and we see it every day that GPS system needs time correction (Due to Time Dilation perdicted in SR)...
  12. U

    Time travel and the double slit experiment?

    I'm pretty much a newbie to this quantum physics stuff, but the one thing that really blows my mind is the double slit experiment. I just don't make much sense. Anyways, I was wondering, could the interference pattern caused by firing a single particle through the double slits be the case of...
  13. V

    Exploring Time Travel with Objects' States

    Hi! I always wonder, why "Time Travel" equation make use of velocity of an object ( speed of light etc.) Why not it is related to the state of objects constituting the universe. Say, in my tiny imaginary universe, that just consists of me and a road from point A to B. A...
  14. M

    Is Observing Starlight a Form of Time Travel?

    I was looking at the sky and I began to think about the stars. Obviously they emitted their light years ago because as we know, light is fast but not instantaneous. That the sky and stars as we see them, are not anymore because its only a view of their light omitted years ago. My point is that...
  15. D

    Is time travel possible and does it mean we have no free will?

    "Once confined to fantasy and science fiction, time travel is now simply an engineering problem." Michio Kaku If time travel were to be operational right now and I want to go 5 days towards the future and record all the events that have transpired, and go back again to the present time, am I...
  16. T

    Impossibility of Backwards Time Travel

    Sorry, but I only have very limited knowledge in physics. I came to ponder the concept of time travel. Backwards time travel has been a topic of discussion for as long as man has pondered his own existence. However, what this simplistic discussion attempts to do is to explain how backwards...
  17. D

    Time travel will never be possible.

    Simply because there is no past or future to go to. Only the present exists. Or at least that is what I think. If time travel is possible, why do we have no visitors from other times?
  18. P

    Is Time Travel Possible Through Black Holes?

    Black holes-- time travel? Is it plausible for something to time travel by means of a black hole, or is that entirely science fiction?
  19. N

    Time Travel Proposal: Observing Objects from the Past?

    Hello, so last night something occurred to me that I thought perhaps some of you might find interesting and enlighten me with validation. As I understand light travels at c in a vaccum. When light propogates through our atmosphere and through other particles it travels slower than c. Does...
  20. A

    Possible Proof of Time Travel: Is it Physically Possible?

    could this be proof of time travel? and would it be physically possible to one day time travel if this is not real? http://www.youtube.com/watch?v=TiIrpEMbQ2M&feature=player_embedded
  21. G

    Time Travel: Make me a believer

    This is not an attempt at humor or controversy. I spend my spare time trying to find truth. I have been trying to understand some of Physic's theoretical ideas, and to my chagrin, many of them seem preposterous. I hope there are people out there that have the time and patience to help me...
  22. nomadreid

    Dark Matter and Thorne's unlikely time travel

    There are a lot of "IF's" in the following, so this may be more a question of logic than of physics. Also, I have two questions revolving around the same themes; they are independent from one another so a response can be to one or both of them. (1) In...
  23. D

    Traveling at the speed of light and time travel?

    I understand that modern day Physics allows for travel into the future, but not the past. I understand that time slows down the closer and closer you get to the speed of light, so that you never exceed that limit. But what if you meet it? I know because of the laws of Physics, you couldn't meet...
  24. B

    Please set me straight about velocity based time travel

    I just finished watching a hawkins program about time travel that theorized that the faster an object travels through space, the slower it moves through time. The example involved a trip to Alpha Centauri at 99.9% light speed. He claimed that although the trip would only take a few years to...
  25. S

    Time Travel and the Conservation of Matter Problem

    Imagine the following experiment: Scientists have made a machine that can create a traversable wormhole and can also accelerate one end at near the speed of light and bring it back. A time machine. Suppose the dilation between the two ends is 10 years. As soon as the experiment brings...
  26. M

    Time travel paradox only due to choice

    The title is the best way I could group this thought. And the following is most likely sloppy so I do apologize. I get the 'feeling' (subjective I know), that the measurement effecting the outcome i.e. only being able to measure position over velocity, collapsing wave functions, etc... comes...
  27. B

    Is Time Travel Possible and How Does it Work?

    Hello. I've been on this forum for a while. Though I never really bothered clicking the "register" button until now. I am no scientist (In fact I still haven't reached university yet), so this might be a bit, well, simple-minded. Recently I've had some thoughts and discussions with my friends...
  28. J

    Physics Are there physicists that study time travel

    I wonder if there is a profession in physics where physicists study time travel. If not, are there any research fields that correlate towards the study of time travel. I'm just curious.
  29. M

    What Are the Most Plausible Theories for Time Travel?

    Hi, I am currently working on a project over the summer, entitled 'The physics of time travel'. One of the first things I need is feedback from academics and students involved in physics. Are there any texts/books I should be reading? Also, it would be great if anyone has the time to fill in...
  30. @

    Can Black Holes Break the Rules of Time?

    hey people..! I need to ask that whether time travel is possible ?.If speed of light is achieved..however besides this i also think that if speed of light is achieved nothing could stay at that speed virtually...what do you people think..?? Secondly, i was thinking that how do we know that...
  31. I

    How to get involved in time travel research?

    Time travel is always something that has deeply interested me... the theory of relativity and modern physics have shed more light on what time is but, even today, is 'time travel' actually a respectable field of research on its own? Thanks.
  32. EnumaElish

    Time travel and Asimov's Eternals

    Time travel and Asimov's "Eternals" I was reading Asimov's The End of Eternity over the weekend. The plot: Through time travel, the Eternals have been manipulating history so as to avoid tragic events (wars, etc.) that happened in the pre-manipulation version of history from having happened...
  33. Jonnyb42

    Is it worth striving for time travel in order to achieve potential immortality?

    Please excuse the far-fetched nature of this thread. I only ask of your opinions. If you do not like these kinds of threads, then don't read it! In your opinion, would it be worth the effort to strive to build a time machine, so that you could go to the future where the medical field has...
  34. Jadaav

    Exploring the Possibilities of Time Travel: The Science and Theories Behind It

    is time travel possible? If yes, how is it possible to travel through time? Can we travel in the future? Can we travel back in the past?
  35. M

    Can Time Travel Reveal Tasks Before Completion?

    About Me: I am not a physics student, but I do have a physics question. Question: The question is, assuming it is possible to travel into the future: could it be possible to learn whether a task performed in the future had occurred before it had been performed? Theory: You are capable of...
  36. L

    Time Travel Question (from A Briefer History of Time )

    Time Travel Question (from "A Briefer History of Time") I read the original "A Brief History of Time" and is now reading "A Briefer History of Time". :P There is a part about time travel that confuses me. Does anyone want to enlighten me using layman terms? (i am a mathematics major, not a...
  37. C

    Time Travel Possibilities: Examining the Physics of Spacetime

    Michio Kaku stated that current physics does not rule out the possibility of time travel even tho it would take comprimable measures to achieve it, such as the energy of a supernovae, my question is even if you can bend spacetime to that extreme to get to a planet with life on it, how are you...
  38. M

    Is SR-allowable time travel future-only ?

    Is SR-allowable time travel "future-only"? Relativity theory allows for the possibility of time travel to the future, according to time dilation as illustrating by the twin paradox. Wikipedia says, "it is currently unknown whether the laws of physics would allow backwards time travel." My...
  39. A

    Can Time Travel Alter Our Perception of Reality?

    Hey 1. If a person drive a car in 100 kph, while another person walks in 5 kph, will then time go slower for the driver? I saw a video on youtube about Einsteins theory of relativity. They said that the faster we travel, the slower time goes. So will then the person who walks be longer into...
  40. S

    Exploring Time Travel: How Do We Explain Its Possibility?

    Special theory of relativity says that in the absence of an absolute reference, different observers may disagree on the time at which a particular event happened. With this knowledge, how do i explain time travelling? Every observer should be witnessing the same set of events (though their...
  41. E

    Hypothetical time travel & time dilation

    Homework Statement <Q1> “Super Ted”, a famous children’s TV cartoon character, has just leant of an evil deed carried out by “Texas Pete” who had opened a farm gate at A and let all the sheep out onto the train tracks and roads. It shows that everything was normal until Super Ted boarded...
  42. A

    Does the Universe's Expansion Affect Time Travel?

    If time travel is possible,is there any problem of universe revolving which would affect time travel,because as,Gödel was the first person who found solution to Einstein equations involving time travel,but he disappointed when astronomers told that universe is expanding,but the net spin of the...
  43. M

    The quantum physics of time travel

    anyone read or have opinions on The Quantum Physics of Time Travel by David Deutsch and Michael Lockwood? He talks about closed time like curves and if we followed them it would end up taking us to the past to participate in events, shake hands with former selves etc I was a little...
  44. J

    Light speed spaceship time travel conundrum

    Let’s say we have a spaceship capable of traveling at the speed of light, and a planet we can visit 50 light years away. From earth’s perspective if we can track the ship we would be able to see it was traveling at the speed of light and we would also see it has taken 50 years to complete the...
  45. V

    What does General Relativity Theory say about time travel?

    I am going to give write an essay about time travel. What does science say? What is the arguments for possibility and against possibility. And what does General Relativity Theory say about time travel? Theoretical possible, but not practically?
  46. L

    Faster than light time travel through controlled, spatial distortion

    I have recently heard of a theory that states that faster than light time travel is possible by disrupting the fabric of space-time using tachyons, to create a makeshift wave behind a future spacecraft of some sort. It states that by doing this, one creates a bubble around the spacecraft ...
  47. S

    Is this idea of time travel consistent with relativity?

    This is the explanation I give people when they ask about time travel. I am only an undergrad so I just want to ask the more experienced people here if this is correct. Thanks... Time travel in the context of Einstein's relativity: So we all know that time travel into the future is easy...
  48. T

    Exploring Einstein's Theory of Relativity: Can Time Travel Be Possible?

    Time time time Can the laws of gravity permit curving space and time in such a way as to make time travel possible. Einstein's theory of relatively states that the space/time continuum can be flat, but it can also be curved by gravitational fields. Perhaps time has three folds 1...
  49. S

    Debunking Time Travel Speculations: The Truth Behind Going Back in Time

    From what I've seen, most speculations of time travel seem to say that when you go back in time, everything else around you returns to an earlier state that it used to be. For example, if you stand outside your house and go back in time, the house will "un-build" itself and there will be nothing...
  50. D

    Do wormholes actually exist and can they be used for time travel?

    How is time travel possible? i understand that we can warp and modify time but i don't understand the concept... Is there any evidence to suggest that there are wormholes? if so how are they created?
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