# Fermi's Paradox and Time Travel. **URL:** \ **Category:** Great Debates\ **Created:** [February 10, 2011, 6:01am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867 "2011-02-10T06:01:44Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Sitnam](https://avatars.discourse-cdn.com/v4/letter/s/6a8cbe/32.png) [@Sitnam](https://boards.straightdope.com/u/Sitnam)\ **Post date:** [February 11, 2011, 12:01am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/21 "2011-02-11T00:01:10Z")
Maybe this era is like flyover country. ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [February 11, 2011, 12:29am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/22 "2011-02-11T00:29:13Z")
> [@bouv](#): > > I think if time-travel is ever developed, it will only be one way…to the future. What do you mean by “ever developed”? :dubious: We can already time-travel into the future. ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [February 11, 2011, 12:53am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/23 "2011-02-11T00:53:06Z")
I think this relates to Fermi’s Paradox perfectly. The reason we apparently are alone in the Universe is because every time one of the trillions of advanced alien species visits us, some temporal cops from the future come back and stop them from making their presence known. Just yesterday a malfunctioning alien ship vaporized the White House instead of quantum sampling it. Oops! The T-Cops fixed it though. ---
**Author:** ![The\_Tao\_s\_Revenge](https://avatars.discourse-cdn.com/v4/letter/t/73ab20/32.png) [@The\_Tao\_s\_Revenge](https://boards.straightdope.com/u/The_Tao_s_Revenge)\ **Post date:** [February 11, 2011, 12:53am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/24 "2011-02-11T00:53:07Z")
> [@Steve\_MB](#): > > If time travel into the past prior to the creation of the time machine is possible and the outcome of events is not fixed, there is a risk of altering history in a way that erases the machine from existence. As the number of trips increases, the probability of this approaches one: Further intelligence means the machine will be rediscovered given enough time, so the only stable time line is the one where intelligence fails to evolve, or is snuffed out. This may answer the Fermiparadox as well. Any species that advances long enough to invent time travel ceases to exist as an intelligent species. ---
**Author:** ![The\_Tooth](https://avatars.discourse-cdn.com/v4/letter/t/c67d28/32.png) [@The\_Tooth](https://boards.straightdope.com/u/The_Tooth)\ **Post date:** [February 11, 2011, 1:05am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/25 "2011-02-11T01:05:19Z")
> [@Czarcasm](#): > > Time travel into the future is very complicated- Pfft. I can do it in my sleep. I often find it to be later than it was. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [February 11, 2011, 1:16am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/26 "2011-02-11T01:16:26Z")
> [@levdrakon](#): > > I think this relates to Fermi’s Paradox perfectly. > > The reason we apparently are alone in the Universe is because every time one of the trillions of advanced alien species visits us, some temporal cops from the future come back and stop them from making their presence known. > > Just yesterday a malfunctioning alien ship vaporized the White House instead of quantum sampling it. Oops! The T-Cops fixed it though. They aren’t meticulous though. Any time you notice something that doesn’t quite make sense…that’s leftover phase variance of the timeline. Only explanation. ---
**Author:** ![sisu](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@sisu](https://boards.straightdope.com/u/sisu)\ **Post date:** [February 11, 2011, 1:47am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/27 "2011-02-11T01:47:38Z")
Yeah I am time travelling into the future, it’s just in real time! ---
**Author:** ![Susanann](https://avatars.discourse-cdn.com/v4/letter/s/7ab992/32.png) [@Susanann](https://boards.straightdope.com/u/Susanann)\ **Post date:** [February 11, 2011, 2:42am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/28 "2011-02-11T02:42:44Z")
> [@John\_DiFool](#): > > [Cue the old lady who was apparently on her cell phone in a 1920’s movie](http://cubiclebot.com/videos/time-traveler-spotted-in-charlie-chaplins-1928-film-the-circus/)… Amazing! ---
**Author:** ![That\_Don\_Guy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/that_don_guy/32/538_2.png) [@That\_Don\_Guy](https://boards.straightdope.com/u/That_Don_Guy)\ **Post date:** [February 11, 2011, 4:02am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/29 "2011-02-11T04:02:38Z")
> [@Alessan](#): > > Maybe time travel creates an entirely new universe (the whole “trousers of time” effect). In that case, maybe we’re the original reality - the one that invents time travel - and the ones we travel too will be alternate earths. That’s my theory as well, sort of. Assuming that teleportation is impossible without passing through the points between the source and destination in some way, presumably the same applies to time, so in order to go back to some time in the past, you go through all of the moments in time between now and then. The problem is, just as you can’t move through space if there is something solid there, there will always be something solid preventing your travel into the past - namely, yourself. Your time-traveling self you would have to occupy the same space that the “1/1,000,000,000 of a second ago” version of you was occupying at that time. (I chose such a small amount of time because even if you were moving at the speed of light, the most you could move in that time is about 30 cm.) The only way to get to the past is through some hole connecting two different universes, one of which parallels our current one but in its past. – Don ---
**Author:** ![Heyoka13](https://avatars.discourse-cdn.com/v4/letter/h/b9e5f3/32.png) [@Heyoka13](https://boards.straightdope.com/u/Heyoka13)\ **Post date:** [February 11, 2011, 4:26am UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/30 "2011-02-11T04:26:01Z")
Perhaps some universes in the multiverse have as an innate characteristic of their existence the allowance for mobility in the time dimension. (for the moment, I am assuming our universe is not like that) For universes with ‘easy’ mobility in time, the subset of universes that also allow changes in their timeline would seem to be a given. However (and yes, there is a clause in the operating system of our universe that requires these ‘howevers’ in threads like this) those universes with ‘easy’ time travel, and that also ‘tolerate’ changes to their past, would rapidly become Chaotic (yes, capital C Chaotic) and would not be suitable for life forms. For instance, for microbes on a planet with evolution allowed, upon encountering something that will eat them, eventually one will by accident, evolve the ability to ‘blink’ back in time and ooze in the other direction and avoid being eaten. This will disrupt all subsequent evolution on that planet, and since all the descendants of that microbe will have the ability to ‘blink’ and avoid being eaten, and without ‘death’, this most advanced life form on that planet (this time mobile microbe) will be a dead end for life on that world. And all the worlds in that universe will face the same problem. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [February 11, 2011, 1:30pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/31 "2011-02-11T13:30:30Z")
> [@Heyoka13](#): > > Perhaps some universes in the multiverse have as an innate characteristic of their existence the allowance for mobility in the time dimension. > > (for the moment, I am assuming our universe is not like that) > > For universes with ‘easy’ mobility in time, the subset of universes that also allow changes in their timeline would seem to be a given. However (and yes, there is a clause in the operating system of our universe that requires these ‘howevers’ in threads like this) those universes with ‘easy’ time travel, and that also ‘tolerate’ changes to their past, would rapidly become Chaotic (yes, capital C Chaotic) and would not be suitable for life forms. > > For instance, for microbes on a planet with evolution allowed, upon encountering something that will eat them, eventually one will by accident, evolve the ability to ‘blink’ back in time and ooze in the other direction and avoid being eaten. This will disrupt all subsequent evolution on that planet, and since all the descendants of that microbe will have the ability to ‘blink’ and avoid being eaten, and without ‘death’, this most advanced life form on that planet (this time mobile microbe) will be a dead end for life on that world. And all the worlds in that universe will face the same problem. If we culture them, could we harvest all-organic resublimated thiotimoline? ---
**Author:** ![Asympotically\_fat](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)\ **Post date:** [February 11, 2011, 2:29pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/32 "2011-02-11T14:29:30Z")
I guess we’re not ready for this thread yet, but our kids are going to love it. ---
**Author:** ![BMalion](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@BMalion](https://boards.straightdope.com/u/BMalion)\ **Post date:** [February 15, 2011, 5:54pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/33 "2011-02-15T17:54:10Z")
> [@these are my own pants](#): > > one of the biggest problems facing time travllers is the power needed to facilitate their temporal sojourns. You need something of the order of 1.21 gigawatts, which is only obtainable by stealing plutonium from libyans or from a lighting bolt striking a clock tower. **1.21 gigawatts!!!?** ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [February 15, 2011, 7:57pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/34 "2011-02-15T19:57:29Z")
> [@Czarcasm](#): > > Time travel into the future is very complicated-wouldn’t it be easier to shoot that conduit backwards and let the Big Bang provide the juice? A big mystery is why there is more matter than antimatter in our universe. You just solved it - people from the future siphoned the antimatter off for use in energy generation. Could I come to your Nobel ceremony? ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [February 15, 2011, 8:04pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/35 "2011-02-15T20:04:46Z")
> [@Voyager](#): > > A big mystery is why there is more matter than antimatter in our universe. You just solved it - people from the future siphoned the antimatter off for use in energy generation. > > Could I come to your Nobel ceremony? You will/did. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [February 15, 2011, 9:06pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/36 "2011-02-15T21:06:04Z")
As I’ve said before. If you have a virtualy infinite number of future time/space travelers that have a virtually infinite number of time/space destinations to visit then any given time/space coordinate will not be overrun by time travelers. Hell, if time travel is hard or expensive or not many folks do it (and honestly, even if feasible I can’t imagine that NOT being the case) then at any particulary time space coordinate you’d be fortunate to have ANY time traveler “there”. Its like moonites wondering why the hell the moon isnt overun by human vistors. And that doesnt even take into account that traveling through time might be like traveling through space in a highway sense…there might be a finite “volume” of space/time available to “pass through” to reach a given destination…so even if every historian from the future wants to see JFK get shot, only a finite number can get through the keyhole to see it. IMO this “where are all the time travelers” paradox is just like the Fermi Paradox. It makes for an interesting discussion but once you get back to some semblance of reality there aint no paradox to be found. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [February 16, 2011, 1:55pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/37 "2011-02-16T13:55:21Z")
> [@These are my own pants](#): > > I guess we’re not ready for this thread yet, but our kids are going to love it. Don’t you mean our grandparents will love it? ---
**Author:** ![moldybread](https://avatars.discourse-cdn.com/v4/letter/m/7ea924/32.png) [@moldybread](https://boards.straightdope.com/u/moldybread)\ **Post date:** [February 16, 2011, 5:04pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/38 "2011-02-16T17:04:02Z")
Time travel is possible and is happening all the time, just not as you might think. Read about time dilation [http://en.wikipedia.org/wiki/Time\_dilation](http://en.wikipedia.org/wiki/Time_dilation) ---
**Author:** ![Asympotically\_fat](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)\ **Post date:** [February 16, 2011, 5:24pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/39 "2011-02-16T17:24:01Z")
> [@moldybread](#): > > Time travel is possible and is happening all the time, just not as you might think. > Read about time dilation [http://en.wikipedia.org/wiki/Time\_dilation](http://en.wikipedia.org/wiki/Time_dilation) That’s slightly different, Fermi’s paradox refers to people travelling backwards in time. ---
**Author:** ![kaylasdad99](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kaylasdad99/32/3398_2.png) [@kaylasdad99](https://boards.straightdope.com/u/kaylasdad99)\ **Post date:** [February 16, 2011, 6:05pm UTC](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867/40 "2011-02-16T18:05:13Z")
> [@Jim\_B](#): > > I don’t know if Fermi’s Paradox is the right term, but seems to apply here: If time travel is possible (a _big_ “if” I realize), then where are all the tourists from the future? Okay, I can’t resist any longer; I’m tellin’ him. **Jim B** , _all_ of us are the time tourists. You, personally, are one of only 435,016 people currently on the planet who originated in this timeline. And you’re the only one on the SDMB. [Previous page](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867.md?page=1) [Next page](https://boards.straightdope.com/t/fermis-paradox-and-time-travel/570867.md?page=3)