# How to avoid FTL as a plot device?

Many SF stories feature faster-than-light travel as essentially a trope: Roddenberry has stated that the Enterprise travels at the speed of plot. As an allegory of the south seas, or some throw-away method to introduce people to a place to have an adventure or meet a different culture, it's just used to preserve the time scale we are used to.

But “hard” S-F has moved away from FTL over the last 20 years or so, and we see everyone from Greg Egan to Alastair Reynolds crafting mind-bending stories where the speed of light is still a hard limit.

But, more generally, how can we write an adventure story without FTL? How do you deal with the time scales involved? Even Egan’s universe seems less believable with society remaining unchanged for thousands of years while characters are transmitted at light speed.

How can characters encounter “strange new worlds” etc. without resorting to a trope?

• According to the European Space Agency, stars in a globular cluster can be 100-1,000 times closer together than stars in the solar neighborhood. On average, this might be on scales comparable to the edge of the Solar System (though that distance is ill-defined; I don't quite know what they mean by that). Either way, it's a lot easier to travel from a planet orbiting one star to a planet orbiting another star. Jul 14 '16 at 23:00
• Unfortunately, according to Sigurdsson (1992), planets orbiting stars in number densities at this level can stay orbiting for about 100 million years, at most. That's not enough time for complex life to develop, and it means that at any given time, there may be less planets per N stars in a globular cluster. Jul 14 '16 at 23:01
• Travelling at relativistic speed would mean time dilation would be significant. For example, travelling at 99.99% the speed of light to a star 100 light years away would only take 1.4 years (from the traveller's perspective). Jul 15 '16 at 1:26
• @user52673 Of course, a notable side effect is that everyone you knew at home ends up outside of your light cone. Depending on your relationship with them, this may or may not be desirable. Jul 15 '16 at 14:59
• @siliconpi, So, only 50 years pass inside the membrane before the Sun turns into a red giant and engulfs the Earth. Jul 15 '16 at 17:17

Check out the novel Lockstep by Karl Schroeder, it started from the concept of how to write a classic space opera story without FTL.

In Lockstep, the interstellar empire adheres to a system called 360/1 lockstep, where everyone on all worlds and ships spends 1 month awake, then 30 years in cryo-sleep. So, any travel of less than 30 years can effectively be scheduled to happen overnight, and a journey that would take 300 years experientially takes 9-10 months.

• Lockstep is a good novel. Indeed it is a different take on the problem. Jul 15 '16 at 2:54
• @PeterA.Schneider How would technology advance if everyone was asleep? Jul 15 '16 at 21:01
• Why would people submit themselves to such a scheme and how is it enforced? Jul 15 '16 at 22:43
• IIRC (it's been a couple years) the WHY would people submit is, the leaders of the main government had a monopoly on the Cryo unit technology so your choice was either go along with the system, or have no trade, no access to cryo sleep systems, and have to deal with real-time sublight transit if you wished to move between colonies. Basically socio-economic strangle-hold. Jul 15 '16 at 23:56
• @Azor-Ahai In the story the people in "lockstep" (i.e. sleeping most of real time) live in apparently impenetrable fortress- or castle-like structures surrounded by a "normal" inhabited landscape. In the story the surrounding setting seems to be rural/low-tech, and surrounding technology does not appear to change over decades so that the fortresses continue to be technologically superior (which I thought is implausible). But I haven't read the book which may explain how technology is withheld from the fortresses' surroundings so that they can continue to dominate. Jul 16 '16 at 9:39

From my personal experience in storytelling, I found that FTL reduced the possibilities of scenarios as when FTL was involved, stories focused on differences in space dimensions: other location, culture, etc. The absence of FTL adds an interesting possibility to travel in time (one-direction only: the future). For example, should you have a life-suspension feature for travelers which is at least not totally impossible, space travels means that you will never come back in the place you leave before generations : this allows plots when you can play very long-term politics or investments. You could create local clans, empower them, etc. The "space travelers" could become a distinct social class ruling worlds, setting up rendez-vous between themselves thousands of years in advance.

We probably use FTL because our brains are just not capable of considering alternatives without effort, but non-FTL is not-only hard-science, it has the power to be an outstanding source for stories.

• +1 for actually using the interesting physical properties as a source of new plots rather than recycling terrestrial-bound plots in a space setting. Jul 15 '16 at 15:01
• I remember a story from the 70s (I think) where a long-haul astronaut befriended little girls between trips and planted a story of a fairy tale prince or the like in their mind of so that they would wait for him 10 or 20 years later when they were young-grown-ups and he returned from space, not that much older. Jul 15 '16 at 19:34
• Seems like the travelers would be at a disadvantage, having missed out on eons of social change, technological advancement, major events, etc. that were happening planetside while they were away. But I suppose that could make for an interesting story, too. Jul 15 '16 at 20:14
• Alastair Reynolds - House of Suns is a good example of this type of plot. en.wikipedia.org/wiki/House_of_Suns
– Rich
Jul 16 '16 at 18:58
• The sequel novels in the Ender series are another good example, although FTL communication is possible in that universe, the ability to 'skip' history by spending time in travel and the choice involved in leaving home knowing everyone you left behind will age much faster figure heavily into the plot. Jul 21 '16 at 7:22

How can characters encounter “strange new worlds” etc. without resorting to a trope?

Obligatory: Tropes aren't good. Tropes aren't bad. Tropes are tropes.

You always travel at the speed of plot, because that's why the story exists. If you have a good story in mind and you need to use one such trope, then there's no shame in doing so. All you have to do is establish a set of rules and stick to it.

As far as we know, there's no way to travel vast distance in a timely fashion. So if you want to do that, you'll have to make a choice.

If you want to remain in the harder part of the SF spectrum, I would advise to remain unspecific on how the technology works. If you simply state what it does without explaining the how, nobody can tell which laws you're breaking, so really from a certain point of view you aren't breaking any. Alternatively, you can make up one rule that allows FTL under certain conditions. Once again, you don't have to be specific, just consistent.

With that in mind, FTL is one option. That will allow you to have a planet-of-the-week type of adventure, meet new civilisations by the dozen, etc. Alternatively, wormholes, stargates or whatever else you can think of.

FTL by the way doesn't have to be instant, and it doesn't have to be convenient. Maybe you can only travel from and to specific points in space, which means reaching the damn points in the first place, which can be an adventure by itself.

Another option is to keep it only in one solar system, or one planet even.

Consider that on Earth there are many biomes, many cultures, and that you can't really explore it all in a lifetime. If you have a big planet, with big natural separations, you can realistically have widely different cultures, maybe even slightly different species, on a same planet.

If the story is really about meeting new people, all you really have to do is cross the street. You don't need FTL for that.

Another option is to keep it hard all the way (that's what she said - sorry, I had to) and travel at a fraction of c. That means it takes a relative long time to go to another planet. If you have a self-contained adventure on each planet, it doesn't really matter how much time passes.

However, the time difference can be used to add to the strangeness. Even places you know could be radically different. An example of that is The Forever War. Every time the characters come back to Earth from a mission, they essentially are at a different point in the future where everything is new and weird. That would qualify as strange new worlds.

Another option is alternate realities. Granted, instead on relying on speculative FTL it relies on speculative alternate realities. And you'll still need a thingy to do that. There's an episode of Stargate Atlantis where they find a ship that just jumps from reality to reality, and they all are different in some major way.

You can explore strange new worlds this way. It can be actual strange new worlds if the device is in a different location in each reality. It can be our own world where everything is just slightly off. You can explore differences in culture, and differences in one's life based on how events turn out.

Another option is VR. You don't actually go out there to meet new civilisation, explore new world. You just strap a VR helmet and think you do. So the story happens in your mind/in a video game.

Come to think of it, Assassin's Creed is science-fiction and all you do really is exploring a VR space that recreates a portion of history. If your character believes they're living an adventure, is it different from actually living the adventure?

• Right. One of the reasons things like Star Trek, Star Wars and Stargate need as many planets as they do is because they treat each planet as a uniform whole: The ice planet. The desert planet. The gangster planet. Drop the "planet of the X" trope, too. You don't need to get a whole new planet just because your "marsh planet" storyline is done. A smaller number of planets work if you put more on each planet - both environmentally and culturally.
– R.M.
Jul 15 '16 at 14:53
• "Avoid explaining how it works" leads to worlds that are not just scientifically inconsistent but also economically inconsistent - that is, there are obvious consequences to contravention of fundamental physical laws that would allow anyone who exploits them to obtain god-like advantage over anyone who doesn't. Pretending humans just don't take advantage of those things is even less believable than pretending physics has loopholes. See the related recent questions on magic and "cheating physics". Jul 15 '16 at 14:56
• @R.. Except that if you don't know which rules are broken, all you're making is wild assumptions. The only use of hyperspace on screen in Star Wars is travel. You can speculate all day that it could be used to materialize cheese and that it'd make you the richest cheesemeister-general in the galaxy, but at the end of it the only certainty is that you can travel with it. Jul 15 '16 at 16:26
• @R.M.: That reminds me of the Stargate episode where they by mistake go back through a previously unknown second star gate on earth, located in the polar region, and conclude they landed on an ice planet. Jul 15 '16 at 19:01
• "As far as we know, there's no way to travel vast distance in a timely fashion." Relativity is our friend here. Imagine a spaceship that can maintain a 1g thrust for long periods...the time to travel from Earth, to the centre of the galaxy (~30k light years) is of order 10 years. Crucially, it's only 10 years for the crew, if they turn round and come back to Earth they'll find 60,000 years have passed, but it's entirely feasible to have a 10 year mission covering intra-galactic distances without breaking c. There's some engineering problems, obviously, but it's doable. Jul 16 '16 at 0:20

You could limit your story to one solar system. While Battlestar Galactica has ftl I read somewhere that the 12 colonies where meant to be planets in just one solar system (with several suns I think). Also the firefly universe has no ftl (the movie serenity seems to retcon having ftl real time communication but this could be accidentally). All the worlds in firefly are in the same solar system with several (5?) suns. There are competitions to create solar systems with as much habitable planets as possible. They are in the 100 or even 1000 if I read right. Of course this is highly artificial and does not occur in nature.

For the "strange ne worlds" part of you question:

Firefly has not exactly adventures with strange new worlds. But I think we agree that it has diversified adventures even without exploring new worlds. New worlds that could exist where perhaps forgotten moons or asteroids, outposts etc. If you really really want discovery of new worlds and cultures that are untouched by the characters society, I admit this would be difficult.

I think other answers elaborated enough on choosing scenarios where stars are packed more dense together. Combined with some STL but near Lightspeed drive this will give you traveling times in the range of 1 to 5 years. This is not much more we had in medieval times and before on earth I think. And the spacefarer that returns after 20 years to a place while only aged and experienced 1 or 2 years is a good plot point.

• I was just about to answer very similar to this. Our own solar system is actually interesting and still has lots of unknowns. If a sublight generation/cryo based colony ship arrives at a brand-new solar system rich with planets and moons, you have an entirely new setting for exploration at sublight speeds. Jul 15 '16 at 14:18
• Also consider that you needn't limit yourself to only naturally habitable planets - a space faring civilization can have numerous space-stations, asteroid bases, and nomadic 'space cities' (e.g. Eldar craftworlds). Also, considering the rich variety of Earth's cultures and habitats, there's no reason for other planets to be treated as a 'one-shot' single location in a story - even with advanced form of travel and communication. Jul 17 '16 at 16:58
• You can push this idea pretty far, and imagine potentially naturally occurring (but super lukcy) systems with 20+ habitable planets orbiiting a single star (planetplanet.net/2014/05/13/building-the-ultimate-solar-system). If a system is built on purpose (with everything just-so), then celestial mechanics allows for the possibility of hundreds of planets within the habitable zone of a single star: planetplanet.net/2017/05/03/…. Aug 18 '17 at 12:44

TLDR : Make all distances sublight-feasible.

Start your story closer to the center of the galaxy.

If our backwater world is the starting place for your adventures, your characters will need to cover vast distances to get to anywhere interesting.

But if your characters' ancestors left Earth millennia ago and colonized a world in a more crowded neighborhood (like closer to our galaxy's center), then most of the really long journeys are history and your characters can sleep between planets for years rather than centuries.

-- Roll up from comments --

You should probably set your story in a region where the stars are separated by 3-5 light years in all directions. Any closer and the collective radiation from all of your neighboring stars may bake your characters' new home planets. These stellar distances are just an estimate, so further comments are welcome to work out the details.

-- Roll up from comments #2 --

@ToddWilcox made an excellent suggestion that has become the "Too Long Didn't Read" entry for this answer. If we want to tell a story with lots of wonderful locations and if we want to limit our characters' maximum speed of travel, then as world builders, we need to put our worlds close enough together to make that travel feasible given the time-frames of our stories.

• I feel like this is still ignoring galactic scale. How close would these worlds be, in light years? Jul 14 '16 at 22:52
• Our closest neighboring star is Proxima Centauri and is about 4.5 years away at just under light speed. If we use that as a working minimum distance between life-bearing stars, we could probably fit 20 or so such stars around us at that distance with each of them being at least that distant from each other. 5 years is a long time, but with cryogenic suspension and/or extended lifespans, it would be tolerable. A character might hit a dozen planets in their lifetime at those distances. Jul 14 '16 at 22:55
• @NexTerren Stellar density 500-1000 times denser so somethig like 0.5ly instead 5ly. But may be problems, see HDE 226868 comments in question. Jul 14 '16 at 23:37
• "Far out in the uncharted backwaters of the unfashionable end of the westen spiral arm of the galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety million miles is an utterly insignificant blue-green planet, whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea". Jul 15 '16 at 9:47
• Problem - planets near the galactic core are going to be almost invariably irradiated hellholes, due to the density of stellar radiation. Jul 15 '16 at 13:26

I think you have the answer in your question: "Even Egan’s universe seems less believable with society remaining unchanged for thousands of years while characters are transmitted at light speed."

For characters on an interstellar trip, even home is a "strange, new world".

For instance, take Joe Haldeman's The Forever War, the protagonist's travels are periodically broken up by return visits to an Earth which has left him behind.

If you want to write a story with travel across such unfathomable distances, you'll either need some form of FTL (even Hyperion-style farcasters), or you'll have exceptionally long travel times. Turning that limitation into a strength can help you build a very interesting narrative.

One approach is travel at the speed of light. It needs some handwavium to accomplish but does not create causality paradoxes. For the traveller it is as instantaneous as teleportation, but if he travels 50 light years it is a one way trip 50 years into the future, and the only possible return is to a century in the future of his home.

Check out Ken Macleod's "engines of light" trilogy, where the journey is eight thousand light years, to a destination that was not of the travellers' choice.

A variant is to transport the traveller's mind state by radio or laser signals into a body built at the receiving station. This is easier if s/he is an advanced robotic construct rather than biological. Check out Charles Stross "Neptune's Brood" which includes some intriguing speculation on nature of interstellar money and finance.

• See also Baxter's "Space", which covers the concept well. Humans get "emailed" all over the local area of the galaxy, returning to Earth occasionally to find it decades or centuries in their future. Jul 16 '16 at 0:17
• Greg Egan's Riding the Crocodile also heavily uses the premise of info-teleportation. Jul 17 '16 at 3:39

The speed of travel on any long journey is always a plot device.

If travel is involved, if distance is involved, then the speed of travel and the time taken to travel are key to the plot. If they're not important, if you don't want them to affect the plot in any way, then don't travel.

What FTL travel and FTL comms do is allow characters to not be on the ship, or not be excessively long lived and still see the outward and return journey for a vessel within the space of a reasonable career.

Restricting your ships to STL travel is still a plot device, just as it would be for taking a sailing ship across an ocean, or taking a road trip, rather than flying.

If you want to restrict your ships to STL, that's fine, you just have to consider the implications in a way that FTL travel doesn't.

• With FTL a trip to the next star system is no more significant than a trip on Eurostar from London to Paris.
• With STL it's equivalent to walking to the Channel, swimming across, then walking down to Paris. You're going to have a lot more considerations and a lot more adventures that are part of the trip itself as opposed to start and end destination events only.

Ultimately it's going to be a very different story from one with FTL travel with an entirely different set of considerations. Either way Roddenberry was correct, the ship still travels at the speed of plot.

• What would you say about a story set in an established fictional setting with established technology and travel times, then? Would you still say the speed is a plot device? Jul 15 '16 at 17:45
• @Dronz, I'd say: "ROAD TRIP!" What you end up with is the Scifi equivalent of the road trip story, as you travel towards an arbitrary destination you have adventures. If you don't have adventures then the travel time is completely irrelevant and can be ignored whether FTL or STL. Jul 15 '16 at 17:53

If you can build a rocket capable of accelerating with 1g for the duration of the trip, then time dilation will allow you to travel between any two points in the galaxy while having aged only about 20 years.

A side effect of the constant acceleration is that it will give you 1g of artificial gravity onboard. So you don't need rotation or any other method of achieving artificial gravity.

With 1g acceleration you will achieve relativistic speeds within a year. But to avoid too much aging, you still need to accelerate during the entire trip, even while already moving at relativistic speeds.

If your passengers can live with more than 1g of artificial gravity, you can get to your destination with even less aging.

But regardless of how fast you accelerate there is a caveat. Should you decide to go back to Earth millennia will have passed even if you didn't age.

And though this approach avoids FTL, it still leaves open the question of the energy source for this constant acceleration.

This article will give you much of the math behind travel at relativistic speeds.

You could have your story take place in a parallel universe with different laws of physics. You could have your story take place in a universe that only has newtonian physics and non relativistic quantum mechanics along with some other adjustments that allow life to exist in this universe. Also you could set the speed of light to be much higher than in our universe so that even traveling to a planet $10^{14}$km away in a few hours would be traveling at less than the speed of light.

Have bazillions of space habitats in a single solar system (whether our own in the future, or some other one) and let the diversity of humanity just explode.

Our own solar system could support trillions of people - or thousands of times more than that! There'd be so many people who all do so many things that nobody could keep up with the news... strange, new worlds can be isolated just by huge volume - and thus explored by someone not that far away by distance, but really far away by culture, etc.

Traveling a million miles could pass a trillion people. Months journey (or weeks or days, just say there's more or less infrastructure to get the travel time you want) and thousands of Earths. And don't forget how big and diverse our one Earth is!

Roddenberry is basically right. Indeed most of the episodes of original Star Trek could have been set on a relativistic starship on a 500 year mission to explore strange new worlds etc etc. Then the speed of plot would be sublight.

Flash Gordon has adventures on the planet Mongo. The characters in an adventure Sf story could at sublight velocities, in biosuspension if necessary, and rollick around one earthlike planet in one planetary system. The problems start if you want to have the adventures taking on more than one planet. More especially so if the characters are rattling forth and back between multiple planetary systems.

There are indications there could be planetary systems with more than one planet in the Goldilocks Zone. Also, there is a set-up like Jack Vance's Rigel Concourse where there at least 26 earthlike planets in its Goldilocks Zone. Vance never says this abundance of planets was formed. Suspicious minds are inclined to the dubious hypothesis this was the work of godlike alien super-beings. Others suspect this was the work of super-advanced hypertechnology used by not-so-godlike alien puny beings.

Star clusters and the regions of the galactic centre have a higher stellar density so there are stars with separation distances ranging from 100 to 1,000 AU. This means the nearest stars will be tens of light hours to around a light week away. Spacecraft will still need to have high rates of acceleration to travel from one system to another in times suitable for an adventure story. The main problem plotwise is how human characters got themselves in these astronomical locations in the first place. Unless the characters are all native to such denser regions in an immersive adventure story.

Of course, planetary systems might be close together in an alternative universe where gravitation operates on a different set of principles. Perhaps gravitation becomes negative over suitably large enough volumes of space if the average density of matter exceeds some critical value.

The most difficult way of writing adventure SF in a fictional world where sublight interstellar travel is absolutely commonplace. The real problem is imagining what the social and political institutions will be like in such a world. Naomi Mitchison's Memoirs of a Spacewoman was set in a world where long-range interstellar travel was normal and ordinary, but she didn't spend much time delineating what sort of society this was like.

Imagining super-duper-technology is easy compared to devising the social, cultural and political structures and behaviour in a sublight galactic civilisation. In fairness to Egan, if his society has reached a cultural and technological plateau then there will be relatively little change over even thousands of years. The last time we had something like this here on planet Earth was during the long millennia with palaeaolithic and neolithic cultures. Present Earth cultures social, political, economic, scientific and technological are going through a period of rapid change. Don't expect it to last. Just a ting blip between two long plateaus without very little change. Except, of course, for fashion and other social status game playing.

One example of adventure SF that almost qualifies for no using FTL travel. That is Joe Haldeman's The Forever war. The reason I say almost is because of the collapsar jump travel. But otherwise its interstellar war could have taken within one hundred light years of the solar system and all travel could have been relativistic sublight (if we excise the FTL collapsar jump because it wasn't entirely essential to the working out of the story) and the story wouldn't be very different.

For adventure SF to be gallivanting around the galaxy and somehow remaining in the character's timeframe, both for the adventurers and their stay at home pals, the FTL trope is obligatory. There are a few ways of changing locations to where higher stellar density brings other planets closer, but this stretches things. Loping off to alternative universes is conceptually feasible, but it feels like all too Rube Goldberg a solution.

Biting the bullet and staying conscientiously below lightspeed will require imagining societies and cultures that will be quite alien and unlike anything we have seen historically. Setting adventure fiction in milieux like will be extremely difficult to create and write, and most likely unpalatable for readers.

I like the idea of Virtual FTL that I dreamt up once for a short story I wrote:

1. A slower than light ship with replicators and a receiver dish sets out on a voyage to a distant destination.
2. When the ETA of the ship to its destination = the ETA of light from the starting point to the destination, a laser or other light-based communications medium transmits a digital copy of the crew to the ship's receiver.
3. The ship receives the data, replicates bodies for the crew, and uploads their digital essences into the new bodies.
4. The crew experiences instantaneous travel while remaining forever in their own light cone.

This isn't FTL, strictly-speaking, because nothing is going faster than light, but perceptually to the crew it will be instantaneous.

• How is this any faster than cryo sleep during the trip? The data does not travel faster than light. Jul 15 '16 at 14:59
• The rather important distinction between this and cryosleep is that cryosleep requires the person to actually be inactive for however long the trip takes. Assuming the ship is not traveling at lightspeed but rather some fraction of it, my approach would instead allow crewmembers to be active and carrying out tasks etc. up until the moment would come where they would need to be digitally transferred to the ship - which would take place at the speed of light. It also has other advantages, such as not having to haul around bodies and cryotank mass for the journey, etc. Jul 15 '16 at 15:41

All Warhammer 40K it's made in a universe without FTL.

The universal bureaucracy between planets using oracles and the years and years of delay to send a single order, different generations of a family living all their lives in the same ship through an only travel from one planet to another, using magic to "space-time travel" with a lot of risks...

It's really interesting to read about how they surpass or at least patch the difficulties of conquering the universe without FTL technology.

• That's incorrect. The WH40k universe has FTL travel of the "hyperspace" flavor. It just is extremely dangerous due to its unreliability, possible random side-effects and being populated by eldritch abominations. Jul 15 '16 at 23:07
• Yeah, that's the 'using magic to "space-time travel" with a lot of risks' point. It's FTL in some way, but I see it more like a "entering" another dimension and using it in your favor. There are too much negative factors to consider it a regular form of travel. Jul 18 '16 at 8:38
• It's still not "conquering the universe without FTL technology". It's "conquering the universe with unreliable FTL technology". Also, certain people (like Space Marines for example) travel around the galaxy all the time when there is a war to fight somewhere. Jul 18 '16 at 8:45

If you want a lot of planets without resorting to FTL to reach them, pack your solar system full of planets instead!

This can be due to extreme terraforming - our own system has quite a number of worlds to work with (if you include moons). With advanced enough technology, you could put people on all of them.

Another, similar idea is to set your story in a star system that was engineered by absent precursors. If you include dual-moon systems orbiting around gas-giants, put more planets in the Lagrange points, and double it up with a dual-star system you can squeeze quite a large number of habitable worlds within easy commute of one another. This page has a design for a single solar system with 60 stable Goldilocks-zone worlds - or even more if you allow stellar engineering as well - a great setting for a space opera.

• That’s the same as Hothie and Adam D. Ruppe posted already. Jul 21 '16 at 8:17