# If Time Travel is possible **URL:** \ **Category:** In My Humble Opinion\ **Created:** [January 21, 2014, 2:20pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365 "2014-01-21T14:20:05Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [January 21, 2014, 4:37pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/21 "2014-01-21T16:37:44Z")
Since this requires speculation, let’s move it to IMHO. Colibri General Questions Moderator ---
**Author:** ![Folacin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folacin/32/3195_2.png) [@Folacin](https://boards.straightdope.com/u/Folacin)\ **Post date:** [January 21, 2014, 5:27pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/22 "2014-01-21T17:27:39Z")
> [@Keeve](#): > > Cute idea, but I think you’re wrong. You are confusing time travel being _impossible_ with time travel being _discovered_. > > In other words: As you describe, it is quite likely that with all of those millions of different pasts, the world would stumble into a history where time travel hasn’t been discovered yet. But tomorrow it might get discovered. Or next year. Or eventually. But it will happen - unless it is impossible. And for it to be possible in one sequence of events, but impossible in another, doesn’t make sense to me; you’d need not merely a change to events, but some sort of change to natural law. I think I read the ‘cute idea’ in a Niven article first. However, you’re missing the point by saying “not discovered yet”. If time travel is possible and the past can be changed, that scenario is saying the only stable path for history/existence is one where it isn’t discovered. Any timeline where it is found will be changed until it isn’t discovered. And that would happen as many times as necessary, I guess. ---
**Author:** ![Telperion](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telperion/32/509_2.png) [@Telperion](https://boards.straightdope.com/u/Telperion)\ **Post date:** [January 21, 2014, 5:37pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/23 "2014-01-21T17:37:54Z")
It would be hilarious if it was discovered that time machines have been invented dozens of times and work exactly like in _The Terminator_, but nobody wanted to write a paper on how they turned up in the Victorian era buck naked. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [January 21, 2014, 5:42pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/24 "2014-01-21T17:42:12Z")
> [@Keeve](#): > > Cute idea, but I think you’re wrong. You are confusing time travel being _impossible_ with time travel being _discovered_. > > In other words: As you describe, it is quite likely that with all of those millions of different pasts, the world would stumble into a history where time travel hasn’t been discovered yet. But tomorrow it might get discovered. Or next year. Or eventually. But it will happen - unless it is impossible. And for it to be possible in one sequence of events, but impossible in another, doesn’t make sense to me; you’d need not merely a change to events, but some sort of change to natural law. No, the point is that there’s a timeline where time travel isn’t discovered at all. Are you arguing that in millions of different timelines, there isn’t even a single one where time travel isn’t discovered? It doesn’t matter how obvious it is - it’s possible that the idea got missed. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [January 21, 2014, 5:43pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/25 "2014-01-21T17:43:48Z")
I don’t believe time travel to the past is possible at all, and it never will be. What’s happened has happened, and there’s no going back. Now, I do believe we could send someone to the future. That would require a really fast space ship though, but at least it’s possible. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [January 21, 2014, 6:07pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/26 "2014-01-21T18:07:56Z")
> [@Czarcasm](#): > > Sounds loopy to me. More like timey-wimey…wibbely-wobbely…_stuff._ ---
**Author:** ![Keeve](https://avatars.discourse-cdn.com/v4/letter/k/f07891/32.png) [@Keeve](https://boards.straightdope.com/u/Keeve)\ **Post date:** [January 21, 2014, 6:34pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/27 "2014-01-21T18:34:13Z")
> [@Leaffan](#): > > Now, I do believe we could send someone to the future. That would require a really fast space ship though, but at least it’s possible. Or you can just take a nap, and in 5 minutes, a whole hour will have passed! Alternatively: We’re ALL traveling into the future, and we’re doing it at a rate of 60 minutes per hour. ---
**Author:** ![Chimera](https://avatars.discourse-cdn.com/v4/letter/c/8e8cbc/32.png) [@Chimera](https://boards.straightdope.com/u/Chimera)\ **Post date:** [January 21, 2014, 6:37pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/28 "2014-01-21T18:37:50Z")
[Begging for contact from Time Travelers never ends well](http://www.smbc-comics.com/?id=3243#comic). ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [January 21, 2014, 6:44pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/29 "2014-01-21T18:44:46Z")
> [@Keeve](#): > > Or you can just take a nap, and in 5 minutes, a whole hour will have passed! > > Alternatively: We’re ALL traveling into the future, and we’re doing it at a rate of 60 minutes per hour. [Steven Wright]I put instant coffee in a microwave and almost went back in time.[/SW] ---
**Author:** ![weemart](https://avatars.discourse-cdn.com/v4/letter/w/f14d63/32.png) [@weemart](https://boards.straightdope.com/u/weemart)\ **Post date:** [January 21, 2014, 10:31pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/30 "2014-01-21T22:31:16Z")
> [@Leaffan](#): > > I don’t believe time travel to the past is possible at all, and it never will be. What’s happened has happened, and there’s no going back. > > Now, I do believe we could send someone to the future. That would require a really fast space ship though, but at least it’s possible. If it’s possible into the future but not the past then that means it’s a one way trip. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 21, 2014, 10:46pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/31 "2014-01-21T22:46:06Z")
> [@Laggard](#): > > Isn’t it true that you cannot change something that happened in the past? For example, if you went back to when your dad was a child there is no way you could kill him because that would mean you never existed? So you could try to kill him but you would never succeed? Easily gotten around by postulating that the Many Worlds model of quantum mechanics is true; you travel back in time and kill your parents, and all you do is create a new universe where they and you no longer exist while your original past remains intact. I’ve heard that used as an explanation for why we don’t see time travelers. Every time someone comes back they split off a new alternate universe; so if a million time travelers show up at an important historical event like the Crucifixion there’s not a mob of a million time travelers, there’s a million new universes with one time traveler each. Most of whom may well try to blend in, making it even harder to find evidence. ---
**Author:** ![Atomic\_Alex](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/atomic_alex/32/175_2.png) [@Atomic\_Alex](https://boards.straightdope.com/u/Atomic_Alex)\ **Post date:** [January 21, 2014, 10:51pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/32 "2014-01-21T22:51:16Z")
> [@Chimera](#): > > [Begging for contact from Time Travelers never ends well](http://www.smbc-comics.com/?id=3243#comic). I thought this one was pretty good: _caution for swearword and talking cartoon animals_ [![](https://www.weasyl.com/~ness/submission/366425/ness-mexican-food-gets-amazing-in-2067.png) ](https://www.weasyl.com/~ness/submission/366425/ness-mexican-food-gets-amazing-in-2067.png) ---
**Author:** ![weemart](https://avatars.discourse-cdn.com/v4/letter/w/f14d63/32.png) [@weemart](https://boards.straightdope.com/u/weemart)\ **Post date:** [January 21, 2014, 10:56pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/33 "2014-01-21T22:56:41Z")
> [@Der\_Trihs](#): > > Easily gotten around by postulating that the Many Worlds model of quantum mechanics is true; you travel back in time and kill your parents, and all you do is create a new universe where they and you no longer exist while your original past remains intact. > > I’ve heard that used as an explanation for why we don’t see time travelers. Every time someone comes back they split off a new alternate universe; so if a million time travelers show up at an important historical event like the Crucifixion there’s not a mob of a million time travelers, there’s a million new universes with one time traveler each. Most of whom may well try to blend in, making it even harder to find evidence. Would all 1 million ppl try to blend in? I think if 20 ppl went back to then it would be difficult to make even all of them agree to blend in for many different reasons. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [January 21, 2014, 11:09pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/34 "2014-01-21T23:09:39Z")
> [@Chimera](#): > > [Begging for contact from Time Travelers never ends well](http://www.smbc-comics.com/?id=3243#comic). Reminded me of “Vintage Season”. ---
**Author:** ![runningdude](https://avatars.discourse-cdn.com/v4/letter/r/e9c0ed/32.png) [@runningdude](https://boards.straightdope.com/u/runningdude)\ **Post date:** [January 22, 2014, 2:49am UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/35 "2014-01-22T02:49:43Z")
> [@weemart](#): > > If a person who can time travel where to read this story today and email these guys before August 2013 as requested would the story automatically change to say they got 1 reply? Would I remember that I had read the story with no reply received or would I now remember that they got 1 reply? Or would I need to re-read the story to see that they got a reply? Does the fact that they’ve had no reply mean they’ll never get a reply or is it possible that a person who can time travel will reply once they read the story? > > My head hurts. > > weemart It would show up as a perfectly normal reply; once in the past, the time traveler would interact with the world just like any other person. In fact, before the person went back, he would be able to read the post his future self would have left in the past! Source: personal experience (I read this post on January 28, 2014, just before I arrived _today_ to post it)! ---
**Author:** ![weemart](https://avatars.discourse-cdn.com/v4/letter/w/f14d63/32.png) [@weemart](https://boards.straightdope.com/u/weemart)\ **Post date:** [January 22, 2014, 3:15am UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/36 "2014-01-22T03:15:54Z")
> [@runningdude](#): > > It would show up as a perfectly normal reply; once in the past, the time traveler would interact with the world just like any other person. In fact, before the person went back, he would be able to read the post his future self would have left in the past! > > Source: personal experience (I read this post on January 28, 2014, just before I arrived _today_ to post it)! So in that case they’ll never receive a reply since the reply would already be there and the story would have said they got 1 reply. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 22, 2014, 6:05am UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/37 "2014-01-22T06:05:15Z")
> [@weemart](#): > > Would all 1 million ppl try to blend in? I think if 20 ppl went back to then it would be difficult to make even all of them agree to blend in for many different reasons. The point is that if those 20 people or a million people went back, there would be at least a million separate new universes created, one for each (assuming they went back as individuals). It doesn’t matter if Time Traveler #4629 doesn’t blend in if he’s in another universe; you’ll never hear about him. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [January 22, 2014, 9:00am UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/38 "2014-01-22T09:00:53Z")
> [@runningdude](#): > > Source: personal experience (I read this post on January 28, 2014, just before I arrived _today_ to post it)! I might have done that too, but I won’t know for a while because I wasn’t here then yet. ---
**Author:** ![Laggard](https://avatars.discourse-cdn.com/v4/letter/l/9de053/32.png) [@Laggard](https://boards.straightdope.com/u/Laggard)\ **Post date:** [January 22, 2014, 2:29pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/39 "2014-01-22T14:29:30Z")
> [@Der\_Trihs](#): > > Easily gotten around by postulating that the Many Worlds model of quantum mechanics is true; you travel back in time and kill your parents, and all you do is create a new universe where they and you no longer exist while your original past remains intact. > > I’ve heard that used as an explanation for why we don’t see time travelers. Every time someone comes back they split off a new alternate universe; so if a million time travelers show up at an important historical event like the Crucifixion there’s not a mob of a million time travelers, there’s a million new universes with one time traveler each. Most of whom may well try to blend in, making it even harder to find evidence. Thank you. That makes sense. ---
**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\ **Post date:** [January 22, 2014, 4:03pm UTC](https://boards.straightdope.com/t/if-time-travel-is-possible/679365/40 "2014-01-22T16:03:25Z")
Time travel is possible - in a single direction - to the _ **future!** _ [Previous page](https://boards.straightdope.com/t/if-time-travel-is-possible/679365.md?page=1) [Next page](https://boards.straightdope.com/t/if-time-travel-is-possible/679365.md?page=3)