Does this prove that time travel is impossible?

Physics and electronics discussion, revision, exam and homework help.

Announcements Posted on
TSR launches Learn Together! - Our new subscription to help improve your learning 16-05-2013
IMPORTANT: You must wait until midnight (morning exams)/4.30AM (afternoon exams) to discuss Edexcel exams and until 1pm/6pm the following day for STEP and IB exams. Please read before posting, including for rules for practical and oral exams. 28-04-2013
Sign in to Reply
  1. oh_1993's Avatar
    • Benevolent Member
    • Posts: 673
    Does this prove that time travel is impossible?
    I came up with an idea. In an infinite amount of time, everything that is possible happens. This means that if time travel is possible, it will eventually be discovered and used to travel back in time to a time before the present day.

    But in an infinite amount of time, everything that is possible will happen an infinite amount of times so an infinite amount of people will be travelling to an infinite number of locations at an infinite number of times. That would mean that there would be an infinite number of people entering every possible location on Earth in the present day, which clearly is not the case.

    We would be connected with people on an infinite time span everywhere. And if it is possible then given infinite opportunities it will happen infinite number of times!

    Please tell me what you think. Thanks
  2. StuAndMma's Avatar
    • Exalted Member
    • Posts: 356
    Re: Does this prove that time travel is impossible?
    You think too much.
  3. SnoochToTheBooch's Avatar
    • Vengeful, Imperial Overlord of The Student Room
    • Posts: 4,370
    Re: Does this prove that time travel is impossible?
    I don't know if there's any reason to expect an infinite amount of time, but if there is then I suppose what you say sounds about right.
    Also if you had a machine that could go back any amount of time, you would need something that could somehow transport you through any amount of space too. Otherwise, if you stepped into your time machine today and tried to go back even a short time, you'd just emerge in what at that time would be some lonely place in space, just waiting for the earth to catch up as it travels through the galaxy. I definitely don't think it's possible in the hollywood sense.
    Last edited by SnoochToTheBooch; 28-02-2012 at 23:09.
  4. Stonebridge's Avatar
    • Community Assistant
    • TSR Demigod
    Re: Does this prove that time travel is impossible?
    It only proves that you can't apply the concept of infinity to the real physical universe.
  5. morris743's Avatar
    • Banned
    • Posts: 4,343
    • Warning points: 1000
    Re: Does this prove that time travel is impossible?
    (Original post by StuAndMma)
    You think too much.
    I suppose some people have to think when the majority go fourth like mindless sheep.

    The thinkers are clearly bored...and who can blame them.
  6. Simplicity's Avatar
    • TSR Demigod
    • Posts: 6,688
    Re: Does this prove that time travel is impossible?
    (Original post by Stonebridge)
    It only proves that you can't apply the concept of infinity to the real physical universe.
    He just saying the arrow paradox again.

    The problem is that this has been worked out 150 years ago when analysis was developed.
  7. StuAndMma's Avatar
    • Exalted Member
    • Posts: 356
    Re: Does this prove that time travel is impossible?
    (Original post by morris743)
    I suppose some people have to think when the majority go fourth like mindless sheep.

    The thinkers are clearly bored...and who can blame them.
    Forth*

    Don't walk off that cliff.
  8. angrydanmarin's Avatar
    • Exalted and Worshipped Member
    • Posts: 1,079
    Re: Does this prove that time travel is impossible?
    Though i'm pretty sure that infinity is commonly known as a mathematical and physical impossibility? Thus cannot be grounds for justification of anything physical
  9. Billy Pilgrim's Avatar
    • Exalted Member
    • Posts: 377
    Re: Does this prove that time travel is impossible?
    Yeah it's a pretty old argument, but still a powerful one. Certainly it would suggest that radical time travel is impossible. However, it doesn't affect something more localised; e.g. people may be able to travel back 50 years or so in another couple of thousand years.
  10. morris743's Avatar
    • Banned
    • Posts: 4,343
    • Warning points: 1000
    Re: Does this prove that time travel is impossible?
    (Original post by StuAndMma)
    Forth*

    Don't walk off that cliff.
    Proving my point :rofl:

    Thanks to whoever negged you for this. PM me if you see this please (the negger, not you).
  11. Simplicity's Avatar
    • TSR Demigod
    • Posts: 6,688
    Re: Does this prove that time travel is impossible?
    (Original post by angrydanmarin)
    Though i'm pretty sure that infinity is commonly known as a mathematical and physical impossibility? Thus cannot be grounds for justification of anything physical
    Actually no.

    Mathematician have definitions of infinity and you can deduce useful properties from them. For example, you can deduce that some infinities are bigger than others.

    In physics you have infinities, but you have tricks to get rid of them. Renormalization being the most famous thing.
  12. Raiden10's Avatar
    • Exalted and Worshipped Member
    • Posts: 1,363
    Re: Does this prove that time travel is impossible?
    (Original post by oh_1993)
    I came up with an idea. In an infinite amount of time, everything that is possible happens.
    Why?
  13. nick2012's Avatar
    • Junior Member
    • Location: Luton
    • Posts: 25
    Re: Does this prove that time travel is impossible?
    I have Doctor Who on speed dial for when I need to go back a century or two :cool:
  14. El_Sid's Avatar
    • Exalted Member
    • Posts: 326
    Re: Does this prove that time travel is impossible?
    (Original post by morris743)
    Proving my point :rofl:
    Mmm... Not really, no.
  15. lukas1051's Avatar
    • Vengeful, Imperial Overlord of The Student Room
    • Location: London
    • Posts: 3,680
    Re: Does this prove that time travel is impossible?
    Who says time is infinite? There are many reasons time travel will never be possible, such as the huge number of logical paradoxes.
  16. AGrumpyMole's Avatar
    • Adored and Respected Member
    • Posts: 464
    Re: Does this prove that time travel is impossible?
    (Original post by SnoochToTheBooch)
    I don't know if there's any reason to expect an infinite amount of time, but if there is then I suppose what you say sounds about right.
    Also if you had a machine that could go back any amount of time, you would need something that could somehow transport you through any amount of space too. Otherwise, if you stepped into your time machine today and tried to go back even a short time, you'd just emerge in what at that time would be some lonely place in space, just waiting for the earth to catch up as it travels through the galaxy. I definitely don't think it's possible in the hollywood sense.
    But the people, or beings, may use another dimension that is invisible, to time travel.
    Last edited by AGrumpyMole; 28-02-2012 at 23:31.
  17. around's Avatar
    • Vengeful, Imperial Overlord of The Student Room
    • Location: back row rebel
    • Posts: 3,592
    Re: Does this prove that time travel is impossible?
    (Original post by oh_1993)
    I came up with an idea. In an infinite amount of time, everything that is possible happens.
    If you flip infinitely many coins (in an infinite amount of time), the probability that you never flip a tail is 0...
  18. StuAndMma's Avatar
    • Exalted Member
    • Posts: 356
    Re: Does this prove that time travel is impossible?
    (Original post by morris743)
    Proving my point :rofl:

    Thanks to whoever negged you for this. PM me if you see this please (the negger, not you).
    Ah but of course, you labelling someone a conformist by using a term that is ubiquitously used to label people as such makes me the 'sheep'.



    Oh, and try not to cry over the neg. I'm almost tempted to neg you myself now just so that you'll have trouble sleeping, but fortunately for yourself I couldn't give one.

    As a last attempt to get back on topic:

    Attached Thumbnails
    Click image for larger version. 

Name:	BITCH-PLEASE_o_103613.jpg 
Views:	4 
Size:	30.7 KB 
ID:	134287   Click image for larger version. 

Name:	time-tunnel.jpg 
Views:	6 
Size:	33.0 KB 
ID:	134289  
    Last edited by StuAndMma; 28-02-2012 at 23:31.
  19. SnoochToTheBooch's Avatar
    • Vengeful, Imperial Overlord of The Student Room
    • Posts: 4,370
    Re: Does this prove that time travel is impossible?
    (Original post by AGrumpyMole)
    But the people, or beings, may use another dimension that is invisible, to time travel.
    I kind of think if it was possible then we'd know about it by now, there would have been future time travellers at every gig hendrix ever played
  20. Simplicity's Avatar
    • TSR Demigod
    • Posts: 6,688
    Re: Does this prove that time travel is impossible?
    (Original post by around)
    If you flip infinitely many coins (in an infinite amount of time), the probability that you never flip a tail is 0...
    Semantically speaking what you are implying is incorrect. Something having a probability of 0 doesn't imply that it won't happen.

    Picking a real number at random has probability zero for each number. But, that doesn't stop me saying 1 even through the probability of me picking 1 out of all the real numbers is 0.
Sign in to Reply
Share this discussion:  
Article updates
Moderators

We have a brilliant team of more than 60 volunteers looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Reputation gems:
The Reputation gems seen here indicate how well reputed the user is, red gem indicate negative reputation and green indicates a good rep.
Post rating score:
These scores show if a post has been positively or negatively rated by our members.