How could a time traveler prove he's from the future?

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,


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.

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.

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.

By telling us how to do it ourselves.

I’d suggest, say, the newspapers from 1970-1980 on microfilm should do nicely.

69, dude

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.

A record of upcoming earthquakes, volcanic eruptions, tidal waves & hurricanes.

Human events wouldn’t alter those at all.

A clock. Yeah.

Kill your younger self, thus destroying reality. That’ll show everyone that you’re for real!

Take that, space-time continuum!

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.

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…)

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.

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.

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.

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.