I'd like your opinion on the real world consequences that this technology would have in the near future (let's say year 2015). Time travel is possible, but you must set a starting point beacon and you'll then travel to it. Imagine the beacon as a car sized electronic device (it has a two meter spherical living space). The recaller is a watch sized device, that you must wear with you, and that will transport anything two meters around it, to the beacon. The process is: - Put recaller on arm. - Get inside the beacon. - Activate beacon at midnight 00:00. Set it at 4 hours. - Exit the the beacon. - Do whatever you want. - At 04:00, everything in a two meter radius sphere around the recaller appears inside the beacon at 00:00 How would that be used? What limits would you set up to be able to use this in a short story? [Edit: I'll add an example of two people using the machine.] Timeline Alpha (the normal one) 00:00 - Person A uses the beacon (4 hours trip). 00:05 - Person A exits beacon. 00:05 - Person B gets into beacon. (2 hours trip) 00:10 - Person B exits beacon. Timeline Beta (Diverges from Alpha at 00:05) 00:05 - Person B' comes back from his two hour trip. 00:10 - Person B' exits beacon. Timeline Gamma (Diverges from Alpha at 00:00 00:00 - Person A' comes back from his 4 hour trip. 00:05 - Person A' exits beacon. 00:05 - Person B gets into beacon. (2 hours trip) 00:10 - Person B exits beacon. Timeline Delta (Diverges from Gamma at 00:05) 00:05 - Person B' comes back from his 2 hour trip 00:10 - Person B' exits beacon.
Obviously the beacon must only exist for a limited time. The longer it exists, the larger and fuzzier the beacon becomes. It is also a single use terminal. If it is used more than once, you have multiple travellers arriving at the same point in time and space, making a nice mess. Variation: The beacon has a time-varying parameter, and the recaller can be tuned to home in on a specific value of that parameter, so the traveller can tune to any elapsed time after the beacon is activated, until the beacon is shut down or destroyed. Perhaps the tuning range of the beacon is limited (the parameter cycles through all it's distinguishable range in, say, 37 hours). There is still a possibility of traveller collision (traveller jelly), but it isn't a certainty. What happens when a traveller activates the recaller? Does a spherical chunk of traveller, the ground he is standing on, air, and the half of a passerby who wander too close pop out of existence at that point in spacetime (followed by a BOOM as air rushes in to fill the space)? And what about matter displaced in the beacon's arrival chamber? Before you say it only transfers solid matter, think about the conseqences of selectively ransferring matter based on the density. Do vital chemicals of life get left behind? Does the traveller die if holding his breath? What about fluids? A two-meter radius sphere is pretty big, by the way. And instead of wearing like a watch, I would put it on a band worn around the abdomen, as close as practical to the traveller's center. Why does the traveller have to start out inside the beacon? Seems to me that as long as the recall time is predetermined, the traveller can be anywhere. Having the recall time determined only by the beacon makes for a decent story limitation. The traveller can't just use it as a Get Out of Peril Free card by punching the recall button just as he sees a gunman pull the trigger on the Uzi aimed his way.
Cog raises important questions about the 2 metre thing. The only way I can see it working is if there is some kind of pressurised chamber. ALL matter inside would then get transferred to the new site. But this might mean it's hardly portable, unless the pressure is created inside some kind of force field. But that still doesn't answer the question of whether or not the traveller can breathe.
Hmm, why? Actually, it can be used as a phone booth, as long as you don't get inside while someone's already inside, nothing can happen to you. Timeline Alpha (the normal one) 00:00 - Person A uses the beacon (4 hours trip). 00:05 - Person A exits beacon. 00:05 - Person B gets into beacon. (2 hours trip) 00:10 - Person B exits beacon. Timeline Beta (Diverges from Alpha at 00:05) 00:05 - Person B' comes back from his two hour trip. 00:10 - Person B' exits beacon. Timeline Gamma (Diverges from Alpha at 00:00 00:00 - Person A' comes back from his 4 hour trip. 00:05 - Person A' exits beacon. 00:05 - Person B gets into beacon. (2 hours trip) 00:10 - Person B exits beacon. Timeline Delta (Diverges from Gamma at 00:05) 00:05 - Person B' comes back from his 2 hour trip 00:10 - Person B' exits beacon. (I'll paste this in the original post, for clarification.) Yes. Exactly. Congratulations for thinking on the air rush. Not displaced, replaced. No limits. Anything in the sphere, including matter and energy. You're right. An abdomen piece could hace a more conservative, thus safer, radius.
The beacon marks a point in TIME and space. If a fixed beacon doesn't vary over time, the longer it exists, the bigger and fuzzier that "point" in spacetime becomes. An exchange? In that case, it's inherently a two-way transfer, and a traveller can move forward in time to a place preselected by a scout traveller, or even by an unmanned robot probe. The traveller travels forward to the designated time, and has his own recall device to return home after a predetermined interval.
Ha, that's what I was going to say. Fantastic film and despite the fact nobody really understands the plot (even, I dare say, Mr Carruth himself) it's an essential watch for anyone into the whole sci-fi time-travel thing. Edit: Not sure how that would work. You'd turn up to the beacon and just as you were activating it, a second you would appear (together with a desk lamp and a pair of knickers or whatever you were doing 4 hours down the line). You need to deal with the space aspect.
What happens in the 2 metre sphere of nothingness left when the traveller gets taken back to the beacon? Horizon Noise - can I just say the desk lamp/knickers part made me laugh heartily. Thanks
I don't follow but am very interested in the reasoning. Please elaborate further. The beacon is used only for the instant it's activated. In that moment it opens two timelines, one is the standard reality, the other is born with the return of the traveller. No, the current occupant stops existing, he's permanently overriden by the returning traveler.
Imagine a river. Water represents reality, distance to the source represents time a floating item in the water is the traveler. At point A (km 0) you put the beacon. in the river. The beacon, in this alegory, is a mechanical device that can deviate the river to a new riverbed. The traveler passes through km0 and keeps going downriver. After 4 km you pick up the traveler take it back to the beacon, put it inside the beacon and deviate the river. The river now goes through the second riverbed, with the traveler, who's wet with water that's 4km older than the water around him. In the original riverbed there's still a 4km long mass of water going downstream with a "hole" where the traveler was when you picked up (and that's now filled with water, as Cog pointed out).
In that case you'd need to transport back to time T0+n, as my point still holds true (n being the amount of time you need to get out of the room before you2 returns). If you transport back to the exact point of activation you'll get the problem I described. Unless you're talking parallel worlds, in which case that takes all the fun out of time travel, epitomised by the grandfather paradox.
Correct, my image of how time works is non-paradoxical. Otherwise I'd have to remove the contradiction in the paradox which is, by definition, impossible. I agree that single timeline paradigm brings the classic time travel fun, at the cost of being absurd. I believe there's fun to be discovered in a multi-timeline paradigm. The question is, what would be the real world consequences of such a machine? Would they be grave enough to force me to limit the machine to a few people of I could try to manage a world where this technology is open to the public.
An actual point in spacetime has zero height, zero width, zero depth, and zero duration. "length" in the time dimension is the duration. For one point in spacetime to locate another, the target point needs to be clearly defined. You called the base unit a beacon, so I assume the recall device locates the point in spacetime defined by the beacon's activation. If the beacon is activated more than once, the beacon is a split target (unless it DOES have a time-varying property), and the recall device has no way of knowing which of the identical signatures to home in on. I am troubled by the "ceases to exist" notion. If you are talking about branching timelines, both exist in metatime. It seems an arbitrary choice as to which is the "real" timeline. And consider this scenario: Traveller enters the chamber, straps on the recall device, and starts the timer for three days. He is replaced by a sphere of freshly hardened concrete. In the traveller's timeframe, he removed the recall devise, and tossed it into a foundation that is being poured. he then goes about his business for three days. Does the traveller cease to exist for three days and then become real again? What about the foundation? Is there now a big empty bubble down there? What is the mechanism that makes this all work out? Where is matter/energy being transferred and balanced?
Oh, I see now. Yes, the beacon needs to send a time signal additionally to its identification, much like a GPS satellite. It's a great detail to add to the description and to play with in a story twist. Thanks. Let me tell you that you're either really smart or have spent way too much time thinking about time machines. There is no "real" timeline. In metatime there's a straight timeline and x hours of branched timeline, with a length equal to the distance from the moment of "ceases to exist" to the moment of the recall and that keeps going forward in standard time. In that scenario: - The traveler keeps living happily in his time-frame/timeline. - There is indeed a bubble inside the foundation. - In the branch they have to clean the machine and remove all the concrete. What do you mean with "the mechanism"? To keep the balance, you have to replace matter by matter-time, which remains constant. ... ... No, it doesn't, crappity, crap, crap. Ok, I see your reasoning, I need to think of a way to transform the "ceased to exist" matter into energy and send it to the "void" in the other side to keep the matter-time balanced. I don't really like the idea of sending the replaced matter, as it is, to the future point, as that would make the base timeline much too complex for the story.
Oh my gosh, that's confusing. If you're actually using this in a short story how would you ever explain it?!
You're spoiling my next thread. Yes, it's something I've though about for a long time. I hope that a more elaborate version of the river allegory works.
What would you be using it for? Why would the travellers want to use this device? Could the same effect not be achieved by creating a computer-generated world that would exist for four hours. This would allow the traveller to live out a scenario risk-free. (I think there was a Bruce Willis film that was similar to this recently - Surrogates, I think it was called.) There seems little point in "diverting the river" as it were, if it's inevitably going to go back to the original state anyway. Anything that happens in that time is pointless. The same effect could be more simply achieved by a computer-generated world that would be so much easier to create and explain, and also avoid all the problems Cog has outlined. That is, unless the beacon was to go wrong, leaving the traveller in the "wrong" time - is that the point in the story? This could also work with the computer-generated world not shutting down as ordered, leaving the traveller stuck.
With the difference that you actually get to live the "future". Imagine you're thinking about doing something risky (not physically, but economically, romantically, etc). You activate the beacon for 24 hours, try your idea and, if it does work out, you do it again in your own timeline. If it doesn't work, you forget about it. A computer generated world can't predict the future. The computer simulation can't tell you whether your cute neighbor will go out with you on a date. The simulation won't tell you which horse will win the race. The simulation can't tell you if your rocket prototype will explode during launch. It can't tell you that North Korea is about to launch a nuclear attack on your country. From there, we enter the world of consequences: - Would betting games still exist? - What would be the effects on the trade market? - What would be the changes on international politics? Which it what I'm trying to imagine. The most important thing I need to understand is: Can I have such beacons on every home and still have a stable world? Or I'll have to restrict it to a single point, possibly controlled by the military. It's the difference between robot stories and, for example, Stargate. You can have a stable world with robots on all homes, you can't have one (or at least it'd be really complex) with stargates on every home.
But what about entropy, and chaos theory? Sure you could go ahead and try something, but there is no way to know that you will get the exact same effects every time.
Not the exact same effects but certainly neither a wild difference. For example, it may be part of the story that a guy does a trip to try to get a date with a girl he likes, which works. Then he goes back and, full of confidence, does it in the updated timeline, and fails, because his confidence is unatractive to the girl for whatever reason. On the other hand, if one guy sees a meteorite coming towards Earth and goes back one day, whatever his changed self influences on Earth, the meteorite is still coming. Inbetween both cases are all the events that are not compeltely independent of the traveler neither completely dependent.
It can if you want it to, just as a time machine can work if you want it to. You're the writer! And it's not even pure fantasy to think such a thing. For example, weather-predicting computers are pretty accurate already. What's the stop a machine predicting a nigh-perfect outcome if it's given the right information to start with. Here's an example: a traveller goes into the future to see the outcome of a boxing match. He then comes back and puts a huge bet on the winner. The winner's odds are then shortened by the bookmaker due to the overwhelming demand. The boxer consequently gets put under severe pressure as the favourite. It gets to him and affects his performance. He loses, losing the traveller a lot of money. Why would the traveller bother with the time machine ever again? And this kind of problem will happen every time. The "real" future will never run the same way as the "diverted stream" because a small thing will change it (see the butterfly effect) even if it's just the knowledge the traveller has from his visit to the future In this way, the computer-simulated world would be no less accurate. Given everything in this thread, my answer would be 'no'. What you can do, however, is use your idea to tell a few butterfly effect stories, but with a twist of the traveller having some idea of what will happen. This could more simply be achieved by using a computer simulation and avoiding all the philosophical questions of time travel. That's my opinion anyway.
You've all left me way back at the starting post. Surely in sci-fi anything goes. Why get embeded down in technology. Let your imagination run riot and tell a good story.
No, in science fiction it's not "anything" goes. The word "science" is in the title of the genre for a reason. If you're really writing science fiction you need to follow accepted scientific principles, or logical extrapolations from those principles (and you can get into highly theoretical areas), or, if you deviate from known science or scientific theory, you need to have a good explanation for it. If you want "anything goes," you should write fantasy. Even so, fantasy has to be internally consistent and logical, but you can do anything you want within the framework you establish.
