Time Travel

The Time MachineOne of the great things about science fiction is how it allows an author to explore the human condition in contexts that ordinary fiction cannot. For example, it can explore the idea of immortality. Is boredom a problem? If you are immortal, but others aren’t, what is it like to see everyone you know age and die? Is it as desirable as it seems?

Some themes occur repeatedly in science fiction. Immortality is just one. A very common one is the idea of alien races — or even intelligent machines. Such stories view humanity through new eyes.

Another common one is time travel, and that is the subject of today’s Sci-Fi Saturday!

tick tock

Second by second.

The problem with time travel is that (unlike aliens or immortality) it’s almost certainly impossible. The idea of going into our own past seems inherently contradictory. On the other hand, we all are traveling into the future at the rate of one year per year.

Of course, that’s not what people usually mean by time travel. Just that we’re all doing it together at the same pace without any special machinery or magic makes it mundane and ordinary.

It turns out that, because of Special Relativity, if you board a fast spaceship, travel away from your start point really fast, and then come back (again really fast, or it would take forever), you “time travel” into the future of the people you left behind.


A time machine!

For example, if your spaceship flies at merely half the speed of light (something we can today foresee accomplishing), and you take a trip to a star six light years away, immediately turn around and come back, upon your return you will have aged 20.8 years.

But everyone on Earth will have aged 24! You have effectively traveled almost four years into the future. At higher speeds, this effect becomes pronounced — you can effectively travel many hundreds of years into the future.

The catch is: you can’t come back. It’s a bit like being in suspended animation for those years (assuming you age more slowly) and then being woken up (this, too, is a science fiction theme that traces back to Sleeping Beauty and Rip Van Winkle).

time tunnel

A time tunnel.

Why is time travel into the past problematic?

A common scenario involves traveling back into the past and killing your father before he marries your mother. (Or less violently, just preventing that marriage.) That action prevents you from being born — it prevents you from existing!

So who came back to prevent the marriage? This is another form of the Liar’s Paradox. (“This statement is false.”) Various authors (and some scientists!) have devised answers to this problem. I’ll explore some below.

The logic paradox I like even better is this: Suppose future Wyrd Smythe comes back and gives me the plans to a time machine. I spend years building the machine so that I can come back and give myself the plans.

time car

A time car!

Where did the plans come from?

It’s almost a version of the Fermi Paradox: If time travel was possible, where are the time travelers?

I have time travel on the brain because I’ve just finished re-reading a bunch of Poul Anderson’s Time Patrol stories.

Anderson’s approach is a fairly common one: the past can be changed, and this does change the future. Time travel was given to us by a version of humanity far into the future (and far evolved above us). They establish the Time Patrol to protect the timeline — in fact, to protect themselves.

time thing

A time portal. (For the record, widely acknowledged as one of the very best episodes of TOS. Written by Harlan Ellison and guest starring Joan Collins. It even won a Hugo award!)

But the timeline has a kind of inertia — actually affecting the future requires the right effort at the right time. Anderson often uses the analogy of a mesh of rubber bands. Stretch one part of the mesh, and it snaps back.

Here, if you do manage to affect the future, your future may vanish. The circumstances that created you may cease to exist. But because you’re in the past, you still exist — you don’t suddenly vanish. You can even travel back to the future to a world that no longer contains your parents.

In that new future, if you do and see things, then go fix the past to restore the original timeline, that new future vanishes, but you still remember what you did and saw. Your personal timeline is consistent.

A plot tension point is that, if Time Patrol people in the past innocently return to the future — a future that’s been altered by the past — they, too, can vanish along with that new future if other agents fix the past and restore the timeline.

time slackers

Time slackers!

Some scientists have floated the idea that time travel into the past might be possible, but doing so puts you into a different timeline. If you prevent “your” parents from marrying, you prevent the “you” in that timeline. This is somewhat similar to the Many-Worlds Interpretation of quantum physics. This idea does away with all the paradoxes of time travel.

Another way authors have dealt with the problem is to invoke a form of “cosmic censorship.” The Superman stories used this idea. Superman sometimes traveled into the past (because he’s super) and tried to change events to create a better, or at least different, future.

But something always happens to prevent those attempts. (Ultimately he stops trying.) The universe finds some way of thwarting his effort.

time futility

Time futility…

In the 2002 film of (H.G. Wells’) The Time Machine, the time traveler goes back in time to prevent the death of his sweetheart at the hands of a mugger only to see her killed by a horse and buggy.

A variation on this is that a time traveler ends up causing the very event they tried to prevent. Upon returning to their present and taking a closer look, they find they were always there and always caused that event.

Time travel also has the interesting idea that we can know we did a certain thing in the past before we go back and do it. (Many authors mention the difficulty of tenses when talking about time travel! The Time Patrol has its own language designed to deal with that.) This invokes the idea of having to actually go back and do it. Or not!


…because not even Superman can change the past!

There is also the idea of what is sometimes called the “block universe” — that the past, present, and future, all exist. Time travel just allows you to move around in the block. If you change the past, it turns out you always did.

One of the more intriguing short SF stories I’ve read involves a race that perceives time as a dimension. They know the future as well as the past. An analogy is made to the telling of a known story. The beauty lies in the telling, not the knowing. (There is, perhaps, a hint of Stoicism there.) The other analogy is of how little children can watch a favorite movie over and over. They can know every word of dialog and still revel in the re-telling.

I really enjoyed the film Looper, which has time travel at its center. One of these days I plan a whole post about it, so I won’t describe it here — see the linked Wiki page if you want details now.


Old timer. And Tommy.

One element I found interesting is how, if an older version of you is in the past, and someone damages (or kills) your younger self, the change works its way up your timeline and ultimately affects you.

It is not the case that you were always damaged and always knew you were; you suddenly become aware that you are now damaged. This is not a new idea — that changes in the past propagate forwards at some pace is just one more take on time travel that authors have used.

If I recall correctly, Gordon Dickerson’s Time-Storm uses that idea. Or maybe I’m thinking of another novel. I do believe the series finale of Star Trek: The Next Generation also used it.


Primer: loop-de-loop!

A film widely acknowledged as almost a tutorial on time travel is the rather inaccessible (and hard to find) Primer. I’ve seen this film twice and been utterly lost both times. Even the diagrams I’ve found that try to explain the film are complex and confusing!

Time travel, unlike immortality, or aliens, or even warp drive (which is also probably impossible), is rife with paradox and built-in contradiction. And that just makes it a fun mine field to explore!

I’ll leave you with a quote from Poul Anderson’s The Shield of Time. It comes from a Danellian — one of our highly evolved distant future selves — to comfort two agents who’ve twice restored the prime timeline from disastrous, future destroying, changes. But that also means they’ve vanished two entire timelines filled with billions, some of whom they’ve come to like.

The Shield of Time

Time Novel.

“Some evolutions are, on balance, better than others. This is simply a fact, like the fact that some stars shine brighter than others. You have seen a Western civilization in which the Church engulfed the state, and one in which the state engulfed the Church.

What you have rescued is that fruitful tension between Church and state out of which, despite every pettiness, blunder, corruption, farce, and tragedy — out of which grew the first real knowledge of the universe and the first strong ideal of liberty.

For what you did, be neither arrogant nor guilt-laden; be glad.”

Stay timely, my friends!

About Wyrd Smythe

The canonical fool on the hill watching the sunset and the rotation of the planet and thinking what he imagines are large thoughts. View all posts by Wyrd Smythe

26 responses to “Time Travel

  • Hariod Brawn

    I read all this article Wyrd; honestly, I did. What I seem to have though, is some pathological condition wherein my eyes glaze over and my brain atrophies at the very moment I see the words ‘sci-fi’, or ‘fantasy’ for that matter. I am serious; my interest levels drop to zero and it’s as if the words on the page are no more than gibberish. I know this is entirely my loss, and it would be unfair of me to make any judgement about the genre due to my condition. There is no cure, and I have to say, I really don’t mind.

    • Wyrd Smythe

      I suppose it’s not that surprising that someone not terribly into fiction would be even less inclined towards science fiction. I actually find the whole thing fascinating; a rather unique characteristic, mi Amigo!

      You’re not the first person I’ve met who seems very alike me in lots of ways, but with some striking areas of radical difference. I seem to have the opposite pathology from you on this… ordinary fiction, which I do like, seems kinda dull to me. I need something to spice it up (one reason I like mysteries and comedies)!

    • Wyrd Smythe

      (But thanks for reading, anyway!)

      • Hariod Brawn

        Oh mate, no need for thanks. I always visit every page you publish because I really appreciate the exchanges we have, and more often than not, you write about things which interest me. The articles about sports which are exclusively American, and those about TV programs that are similarly so, leave me with nothing to say in truth, because of course, it’s all way outside the scope of my experience. As to our sameness/difference, I think I project my interest more inwardly, whereas perhaps(?) it’s true to say you have a fascination for how the external world works. I know you are a spiritual person too, but I sense the balance is weighted differently in our respective cases.

      • Wyrd Smythe

        I think that’s a fair assessment. I’ve been into science all my life, whereas philosophy, spirituality, and theories of consciousness, are more recent pursuits. (Baseball is even more recent — that really only started in 2010!)

        And likewise. You’re one of those bloggers I can count on to write posts (and have comment sections) that intrigue me, even if the subject is outside my purview or primary interests. (Our friend Tina is another. You and she are the only bloggers on my RSS feed.) Whatever else might be said of us, we seem to be all about ideas, and I just love ideas!

      • Hariod Brawn

        Tina is a star; a wonderful mix of intellect and self-deprecating humour. Thank you for your kind words mate.

      • Wyrd Smythe

        Agreed, likewise, and you’re quite welcome! XD

  • dianasschwenk

    The thing I love about Science Fiction is that opens the imagination. I read somewhere once that we have cell phones because people were inspired by the communicators on the original star trek. Remember flip phones?? Someone imagines something, someone else is inspired to invent it. ❤
    Diana xo

  • reocochran

    I used to love “Time Tunnel” television show and loved the “Back to the Future” series, too. I liked how you mention that in a sense, fairy tales embraced science fiction and time travel, too. This was an astute observation, I had not heard before. Did you like the movie, with the guy, Calziel from “Person of Interest? ” Shoot, it is about radio waves and how a son hears something that may solve his mother’s death. Dennis Quaid is in it, too. You may not think that “Forever” is a good show but I absolutely recommend checking it out once, at least. If only to see Taxi star still around, Judd Hirsch plays a son of a police coroner. Time is really confusing but amusing in this show, along with some history being thrown into the plot lines. I enjoyed your post, you have taught me that people on Earth would have aged 24 years while I went far into the distant universe and came back only aged 20.8. Details are interesting, you are so smart!

    • Wyrd Smythe

      You know, the Back to the Future movies just might be a set that is universally beloved. I wonder if there is anyone who actively disliked them? Hard to imagine!

      Fairy tales are the original science fiction! Many of them give us key fantasy themes: fairies and elves, princesses and castles, swashbuckling heroes, dragons and unicorns. Science fiction kicks in, of course, when science does. Jules Verne, H.G. Wells, even Jonathan Swift’s Gulliver’s Travels — all early SF. Also Mary Shelly’s Frankenstein!

      We’ve talked about Forever before. I do like it. It’s eerily like Castle — a show I love. Same attractive homicide cop and non-cop partner idea (also found in The Mentalist). Abe (Hirsch) is Henry’s adopted son from WWII. What’s nice is that in a recent episode Abe was able to reconnect with his long lost family tree. It’s a very good show. Great values and lots of love.

      One thing about that space jaunt… not the distant universe. Six light years is hardly off the block. The Milky Way galaxy is 100,000 light years side-to-side! It’s millions of light years just to the closest neighborhood galaxies! Six LY is nothing! XD

  • reocochran

    “Frequency” with Jim Caviezel and Dennis Quaid. Suspending disbelief, of course, it still had me on the edge of my seat, in the movie theater…

    • Wyrd Smythe

      I’ve heard of it, but never seen it. To me it seems more fantasy than science fiction — it has some arm-waving about a “scientific” explanation, but it’s really about as “scientific” as Spielberg’s little ET and his flying bicycle. Nothing wrong with that, it can be a great movie if it’s well done! :\

  • SelfAwarePatterns

    “It’s almost a version of the Fermi Paradox: If time travel was possible, where are the time travelers?”

    I think this is the crux when considering whether or not time travel is possible. If it is possible, we should see tourists from the future. Saying that they’re secret doesn’t cut it, since it would amount to all of humanity throughout the entire future history of our species complying with that secrecy. (Similar to how all the alien civilizations supposedly out there would comply with a Prime Directive type rule.)

    Although, I suppose time travel might still be possible if someone can block certain times from being visited by other time travellers. Of course, if it is possible, then you’d get into issues of the position of Earth, the solar system, galaxy, etc, all of which are constantly in motion and would have to be accounted for to ensure the would-be traveler doesn’t end up in interstellar space when they reach their destination time.

    • Wyrd Smythe

      I’m not sure I can follow you all the way to “crux” (the causality thing is more the crux for me), but it’s a telling point about time travel and aliens. One can posit Prime Directives and even ultra-max government secrecy preventing common us, but given all the possible visitors… the absence is striking. No poachers? No escaping criminals? No wild rich kids on a lark?

      I didn’t follow this up, but judging just by photos I saw mining for ones to use in the article, there may be a thing of people examining old images for supposed time travelers. Looking for anachronisms. The ultimate would be someone using a “cell phone” in a photo from 1880 or something. (Might be fun to plant some made up ones for April Fools. 🙂 )

      Time travel stories have used the idea of government or secret agency control (Poul’s Time Patrol, for e.g.), and various forms of time censorship pop up. You can’t revisit the same time twice is a common one. Varley’s Millennium uses that.

      I’ve always been bothered by the moving frame thing. The Earth moves 1.5 million miles a day just in its solar orbit. Not to mention the helix that makes as the solar system orbits galactic center. Not to mention etc. etc. How in the hell does time travel take that into account?

      Everything points to TT as impossible. Causality. Visitor paradox. WTF with moving frames. And time is strange; not really a dimension, it just plays one on TV sometimes.

  • rung2diotimasladder

    Aw, you and Hariod are so kind! I was pleasantly surprised to find you talking about me. 🙂

    “One of the more intriguing short SF stories I’ve read involves a race that perceives time as a dimension. They know the future as well as the past. An analogy is made to the telling of a known story. The beauty lies in the telling, not the knowing. (There is, perhaps, a hint of Stoicism there.) The other analogy is of how little children can watch a favorite movie over and over. They can know every word of dialog and still revel in the re-telling.”

    I think this is an interesting premise that you don’t hear too often. I watched some movie last night (believe it or not, I’ve already forgotten the title) and the plot was very predictable, but I couldn’t stop watching it anyway. It’s as if the point is not to find out what happens, but to take in the details of how it happens. I notice that a lot of stories take advantage of this peculiarity of human nature, but rarely do they face it head on.

    I used to watch Alice in Wonderland over and over as a kid until I had the movie fairly well memorized. I remember “playing” it in my head on long car trips, and I’d actually hit “rewind” if I screwed up a line. If I knew I was getting a line wrong but couldn’t remember it, the story would get stuck there and I might have to start the whole thing all over again. It’s so strange how important those details were to me and how joyfully I wanted to see them again and again!

    • Wyrd Smythe

      I love the thought of hitting “mental rewind”! I think part of what’s going on with kids is that they exist in a world crammed full of new things. Nearly everything is new. I think they find some comfort in having something that isn’t new, that allows the onslaught of new information to cease briefly. (It’s the ‘comfort of sameness’ I mentioned in the next post.)

      As an aside, I’ve been impressed by how small children can walk into a room of their house or classroom and instantly spot something that’s changed. Adults take longer or never even notice the change. I think it’s part the high level of attention children pay to their surroundings and that they haven’t been conditioned to expect sameness, yet. They’re incredibly sensitive to changes in their environment!

      Kids aside, there is also about complex stories that we don’t get or see everything the first time around (or second or third). Movies, especially, with visual and narrative, if they are well-done movies, reveal new things on repeat seeings. Good books do that, too. As you say, after the first time through, it’s no longer about what happens, but how it happens. (And that’s a good point that some stories are so obvious in their plot arc, that even the first time through isn’t really about what happens. I hadn’t thought of that before, so thanks for a new thought!)

      I’m planning a post about the “spectrum of repeatability” — how some art works remain enjoyable, even moving and fulfilling, with repeats. Songs and poems seem at one end of that spectrum. Paintings and sculptures, perhaps even more so. The complexity of the narrative seems to push a work towards “once is fine, thanks,” but plays (which have strong narratives) don’t go along with that as much. That may have to do with the variations of each performance (let alone different stagings). Performance of a piece changes each experience of it, even if only slightly.

      Last night, I watched Being There (the classic Peter Sellers film), which I’ve seen several times before (but not in a long while). It was definitely about how the story was told, but also bringing all I’ve experienced and learned since then illuminated it in new ways. (In particular I was trying to see if the title and story really did have any connection with Dasein, but since that’s a new and very dim, fuzzy concept to me so far,… I have no idea! :\ )

      • rung2diotimasladder

        Kids do notice a lot of things about their environment and people too. I wonder if it’s a part of the learning process somehow. For instance, in watching a movie over and over, in seeing the same room again and again, I’m better able to grasp the relationships of things. If everything kept changing on me, I wouldn’t have time to explore those relationships. Children seem to thrive in strict routines (lining up at the door, snack time, nap time, etc).

        Looking forward to your post! For me, certain works deserve repeated study by virtue of their depth. These are often quite complex, but may offer a surface-level satisfaction that beckons you to explore more.

        I just got your email about the movie on TV. Unfortunately, even if I had checked my email in time, I wouldn’t have been able to watch it. We only get a few channels and I basically watch no TV except for PBS. My husband watches all the news we can get, then we’re onto Netflix at night.

      • Wyrd Smythe

        There are even adults who thrive on the sameness of routine (perhaps we all do a bit — the world is ever-changing for us, too). Repeatability is clearly not from just one thing, but multi-faceted. That’s what might make it a decent post, I’m thinking.

        I really enjoyed seeing Being There again (and now hoping all the more you’ll see it and compare it with Dasein — I was wondering if his being a gardener, and the central point point involving “nurturing the garden,” might not connect with “care”). This time through, though, I noticed some aspects that I hadn’t really noticed before.

        It turns on a “mistaken identity” motif (but not a “masked identity” one), and those are really hard to write. The dialog needs to be carefully constructed to carry double-meaning. The character people have mistaken for someone else has to say things that are authentic and natural for that character, but which can be misinterpreted by others. Making that dialog sound right is a challenge, and to my ear they were forced a couple times to cheat a little. I don’t want to plot-spoil, so I’ll just say (if/when you see it) pay attention to the lines, “I like to watch TV,” compared to “I like to watch,” and what results from the latter (twice). That latter line seems a little forced to me, but it has to be said that way to get the desired results.

        Minor quibble, though. It’s still a fantastic movie, and I’d watch it again just to hear that funky jazz version of Also sprach Zarathustra. Actually, silly me, I’m still not used to living in a YouTube world. Here it is. (Also: Y/T seems to have the whole movie available!)

        As you watch, realize that he has never left the confines of the house he grew up in; he has never seen the outside world, except through the (largely sanitized) TV. The only humans he’s ever known are “the old man” (in whose house he lived and was the gardener for) and the maid, Louise, who raised him. (And I don’t know if it’s intentional, but that shot just before he exits the house really invoked Magritte’s The Son of Man to me in how it’s framed and in his costume.)

      • rung2diotimasladder

        I will have to watch it. It looks really different! I might be able to pick it up at our favorite video store…the old fashioned way 🙂

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