# How could a time traveler prove he's from the future? **URL:** \ **Category:** Great Debates\ **Created:** [February 21, 2003, 8:13am UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511 "2003-02-21T08:13:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Ranchoth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranchoth/32/1066_2.png) [@Ranchoth](https://boards.straightdope.com/u/Ranchoth)\ **Post date:** [February 21, 2003, 8:13am UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/1 "2003-02-21T08:13:46Z")
Here’s an odd and somewhat silly question, and one probably more suited to Great Debates than General Questions…If a man traveled back through time from the present day to say, the United States circa 1970, how could he prove he was a time traveler to the people of the time? To be even more difficult, how could you convince the GOVERNMENT that you were really a time traveler, and not just a madman…or even an agent of an enemy government? Well, thanks for your patience, Ranchoth ---
**Author:** ![Dunderman](https://avatars.discourse-cdn.com/v4/letter/d/ecb155/32.png) [@Dunderman](https://boards.straightdope.com/u/Dunderman)\ **Post date:** [February 21, 2003, 8:15am UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/2 "2003-02-21T08:15:28Z")
> [@](#): > > \*Originally posted by Ranchoth \* > **Here’s an odd and somewhat silly question, and one probably more suited to Great Debates than General Questions…If a man traveled back through time from the present day to say, the United States circa 1970, how could he prove he was a time traveler to the people of the time? To be even more difficult, how could you convince the GOVERNMENT that you were really a time traveler, and not just a madman…or even an agent of an enemy government?** I’d bring along some winning lottery numbers and Gray’s Sports Almanac. Should do the trick. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [February 21, 2003, 8:19am UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/3 "2003-02-21T08:19:22Z")
> [@](#): > > \*Originally posted by Priceguy \* > \*\*I’d bring along some winning lottery numbers and Gray’s Sports Almanac. Should do the trick. \*\* Not if time travel alters the course of history. The news of your alleged arrival alone may have enough effect to skew such results. ---
**Author:** ![Dunderman](https://avatars.discourse-cdn.com/v4/letter/d/ecb155/32.png) [@Dunderman](https://boards.straightdope.com/u/Dunderman)\ **Post date:** [February 21, 2003, 8:30am UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/4 "2003-02-21T08:30:02Z")
> [@](#): > > \*Originally posted by scr4 \* > \*\*Not if time travel alters the course of history. The news of your alleged arrival alone may have enough effect to skew such results. \*\* I’ll arrive very, very quietly. Also, if the results are altered, then it was the _altered_ results that were entered into Gray’s Sports Almanac, so the copy I bring back is correct. ---
**Author:** ![TVAA](https://avatars.discourse-cdn.com/v4/letter/t/c57346/32.png) [@TVAA](https://boards.straightdope.com/u/TVAA)\ **Post date:** [February 21, 2003, 8:46am UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/5 "2003-02-21T08:46:14Z")
You can’t change the past by travelling through time. That sort of scenario only makes sense if you assume that the “present” is a privileged reference frame, allowing travellers from it to act without regard to causality while everyone else is frozen into it. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [February 21, 2003, 9:19am UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/6 "2003-02-21T09:19:22Z")
By telling us how to do it ourselves. ---
**Author:** ![E-Sabbath](https://avatars.discourse-cdn.com/v4/letter/e/e19adc/32.png) [@E-Sabbath](https://boards.straightdope.com/u/E-Sabbath)\ **Post date:** [February 21, 2003, 12:14pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/7 "2003-02-21T12:14:01Z")
I’d suggest, say, the newspapers from 1970-1980 on microfilm should do nicely. ---
**Author:** ![lucwarm](https://avatars.discourse-cdn.com/v4/letter/l/e19adc/32.png) [@lucwarm](https://boards.straightdope.com/u/lucwarm)\ **Post date:** [February 21, 2003, 12:25pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/8 "2003-02-21T12:25:10Z")
69, dude ---
**Author:** ![egraaf](https://avatars.discourse-cdn.com/v4/letter/e/c68b51/32.png) [@egraaf](https://boards.straightdope.com/u/egraaf)\ **Post date:** [February 21, 2003, 12:43pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/9 "2003-02-21T12:43:21Z")
I would look into scientific dating methods, like C14 and see if I could find something that people in 1970 would know the exact age for and bring one from the future. For the current time a compact disc would work, it is known when those were invented, so we know how old it can be. The thing I would be bringing would be older than it could possibly be without timetravel. Of course C14 is probably in no way exact enough to show a difference of a few decades, so my scheme might fail miserably. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [February 21, 2003, 4:07pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/10 "2003-02-21T16:07:07Z")
A record of upcoming earthquakes, volcanic eruptions, tidal waves & hurricanes. Human events wouldn’t alter _those_ at all. ---
**Author:** ![athelas](https://avatars.discourse-cdn.com/v4/letter/a/5e9695/32.png) [@athelas](https://boards.straightdope.com/u/athelas)\ **Post date:** [February 21, 2003, 4:09pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/11 "2003-02-21T16:09:49Z")
A clock. Yeah. ---
**Author:** ![Apos](https://avatars.discourse-cdn.com/v4/letter/a/838e76/32.png) [@Apos](https://boards.straightdope.com/u/Apos)\ **Post date:** [February 21, 2003, 4:19pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/12 "2003-02-21T16:19:30Z")
Kill your younger self, thus destroying reality. That’ll show everyone that you’re for real! ---
**Author:** ![vibrotronica](https://avatars.discourse-cdn.com/v4/letter/v/a9a28c/32.png) [@vibrotronica](https://boards.straightdope.com/u/vibrotronica)\ **Post date:** [February 21, 2003, 4:31pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/13 "2003-02-21T16:31:40Z")
> [@](#): > > Kill your younger self, thus destroying reality. That’ll show everyone that you’re for real! Take that, space-time continuum! ---
**Author:** ![Menocchio](https://avatars.discourse-cdn.com/v4/letter/m/9de053/32.png) [@Menocchio](https://boards.straightdope.com/u/Menocchio)\ **Post date:** [February 21, 2003, 4:39pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/14 "2003-02-21T16:39:26Z")
Bosda’s got it. Also, a PDA and tommorrow’s New York Times. Yes, my arrive may displace Page 1’s news, but you’d still see many similarities in the whole paper. ---
**Author:** ![Rider](https://avatars.discourse-cdn.com/v4/letter/r/dc4da7/32.png) [@Rider](https://boards.straightdope.com/u/Rider)\ **Post date:** [February 21, 2003, 4:49pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/15 "2003-02-21T16:49:08Z")
If it could be done, it never has. So never will. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [February 21, 2003, 5:14pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/16 "2003-02-21T17:14:13Z")
> [@](#): > > If it could be done, it never has. So never will. Unless there is an infinite number of orthogonal universes (one of which you merely “jump into”), in which case when the future inventor turns on his machine, he does not appear back in _our_ universe. This also allows paradoxes such as killing yourself, since “you” are merely another person from a different universe with its own causal chain. (I didn’t say I _liked_ this idea…) ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [February 21, 2003, 5:18pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/17 "2003-02-21T17:18:06Z")
Some theorize that perhaps one cannot travel to a time before the time machine is invented, but any time afterwards. I imagine the guy who invents it will be greeted with a LOT a visitors once he hits the ON switch. ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [February 21, 2003, 5:29pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/18 "2003-02-21T17:29:25Z")
> [@](#): > > \*Originally posted by Bosda Di’Chi of Tricor \* > \*\*A record of upcoming earthquakes, volcanic eruptions, tidal waves & hurricanes. > > Human events wouldn’t alter _those_ at all. \*\* Maybe earthquakes and volcanic eruption, but maybe not tidal waves and hurricanes. The latter two events are dependant upon chaotic weather patterns, and it’s quite possible that a single person displacing air could be enough to alter the weather. I assume it would take time to get out-of-synch, so the weather reports would match for a while after the traveler arrived, but eventually they would diverge. And since the traveler would be altering events and other people’s paths and decisions, these differences would spread exponentially throughout human society, making more and more tweaks to the weather. I also wonder if even earthquakes and volcanos have some kind of “chaotic imput” which would make them diverge as well, eventually. Maybe a better choice would be previously unpredicted astronomical events. The actual events happened millions of years before the traveler even arrived anyway, so no matter what he disrupts he can’t have an effect. ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [February 21, 2003, 5:36pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/19 "2003-02-21T17:36:30Z")
Here you go: How would YOU–not someone else, not someone who’s prepared specially, etc.–convince people in the past that you were from the present day if you suddenly woke up, naked and without any possessions (think “Terminator”), in 1970, and with no idea as to how you got there. No studying. No cramming. No bringing back artifacts. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [February 21, 2003, 5:43pm UTC](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511/20 "2003-02-21T17:43:18Z")
> [@](#): > > How would YOU…1970 Wasn’t that the Pele World Cup? I could film an exact recreation of his pass to Jairzhino, his header against Gordon Banks, his dummy to himself _etc_ all from memory before the competition. [Next page](https://boards.straightdope.com/t/how-could-a-time-traveler-prove-hes-from-the-future/156511.md?page=2)