As previously stated, I am constructing a world that has a day lasting nine years. The inhabitants must always be on the move in order to avoid the freezing wastelands of the night, but not so fast as to enter the scorched noon zone.

Most of the people live on the Dusk side, where they evolved. Others have discovered the poles and set up permanent cities, the closest analogs to Earths. Some have even circumnavigated the latitudes to end up at the dawn side.

I am more concerned with the nomadic people. Historically civilization started in the river valleys, where is was easier to set up shop and farm; rather than migrate, hunt or gather. These civilizations would become the empires that lead the way to our modern nations millennia later.

But this world would lack that spark. Imagine that humans live on this world, how does civilization come to be?

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    $\begingroup$ Are there native crops which can live all over the planet's surface? $\endgroup$ – Lio Elbammalf Sep 11 '17 at 7:44
  • $\begingroup$ How wide is the habitable zone on each side of the world? That tells you how long individuals can stay in one place, and perhaps how many different camp sites they'd need to use during a full "day" cycle around the world. Does the world have any major oceans? It's hard to imagine stone-age humans (or the animals they'd be preying on) migrating across something like the Atlantic or Pacific every nine years. $\endgroup$ – Blckknght Sep 11 '17 at 8:37
  • $\begingroup$ @LioElbammalf The plants either drop seeds along the dawn side or asexually reproduce like vines in the dusk. The plants are more mobile here. But yes, the plants do also use fruits to spread seeds $\endgroup$ – TrEs-2b Sep 11 '17 at 9:02
  • $\begingroup$ For example in the time of Sumer, we had what I will call a hybrid. There were a lot of migratory people herding goats and so on and some population in cities. This does not answer your question (hence a comment), but maybe you should consider hybrid solutions and how they might work $\endgroup$ – Raditz_35 Sep 11 '17 at 9:03
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    $\begingroup$ A small thought: If this is not Your first question regarding this particular world, maybe it would be nice to give links to other questions. I, for one, am curious about more details, even if at first glance they don't seem to be directly relevant to this question. $\endgroup$ – Maciej Sep 11 '17 at 16:11

16 Answers 16


The earliest civilizations started in great river valleys, like Sumer (Mesopotamia), Egypt (Nile), China (Yangtze) and India (Ganges). This was because the land near the rivers was easy to irrigate and became fertile for crops. People settled down and abandoned the hunter-gatherer culture when they started to harvest crops. This is called the agricultural revolution and it was the beginning point of civilization.

This is how our civilizations started - they key points is that we settled down because we could produce more food from irrigating the land and harvesting crops than we could from our old hunter-gathering methods.

So if you want to have a civilization that begins without the settling down part, you need to have a way of harvesting lots of food without the need for irrigating land and growing crops. As others have mentioned, animals can move from place to place, but meat is intrinsically more difficult to harvest with a potentially lower yield (consider wheat takes 6-9 months before it is ready to harvest, whereas animals take several years before they are ready for killing).

My solution is to have something like wheat but mixed with something like this plant:

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My thinking is that if you want your civilization to start off on the move, then have them cultivating and harvesting plants that will naturally move with them. Tumbleweeds are one of the best examples of plants that move from place to place, and if they were easily cultivated they might give rise to civilizations that moved with them.

These tumbleweed/wheat plants could be moving slowly across your world, carried by the dusk and morning winds - and as such they could be the only vegetation that can survive all year around (I am assuming night time is too cold & day time is too hot).

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    $\begingroup$ Great idea! For some reason, tumbleweeds never even crossed my mind, but they would probably be the most common type of plants shape, most movement for least effort. Also, I can't help but call them tumblewheat $\endgroup$ – TrEs-2b Sep 11 '17 at 12:05
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    $\begingroup$ tumblewheat is a great name! also, uneven terrain is often described as rolling, but you could give this description a whole new meaning with a line like "the rolling fields of tumblewheat"... $\endgroup$ – Jimmery Sep 11 '17 at 12:19
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    $\begingroup$ Just one problem, how does the tumblewheat survive? $\endgroup$ – G Allis Sep 11 '17 at 22:23
  • $\begingroup$ Survival is an important question - even if you can sort out the nutrient issue, the water issue is practically "insoluble" because water introduces mechanical problems with a dry plant mass that requires open dusty expanses to roll through. In fact, many real tumbleweeds have evolved to explicitly stop tumbling when they reach a wet area so the seeds they carry can germinate. $\endgroup$ – talrnu Sep 12 '17 at 6:16
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    $\begingroup$ @talrnu - I don't see why it couldn't work the same way as long as the tumblewheat is on the dawn side. During the night, any rainfall would be ice/snow and as the night ends, it thaws and creates something like wetlands. The tumblewheat would hit it and stop to germinate. As the day progresses, the wetlands would dry out and the tumbling would resume with a fresh, young crop. Then you just make sure the winds are strong enough to carry the wheat from the late morning areas after germination to the early morning areas to germinate again without noontime catching up. $\endgroup$ – TheIronCheek Sep 12 '17 at 13:57

Your inhabitants could be following big herds of animals, migrating in the same way they do.

If the animals are big, you basically have familiar clans joining to hunt them. Soon, they snatch a few baby animals (perhaps after watching for several "awake cycles" which mother is less aggresive) and tame them. This requires time and patience, but with more people forming a tribe it is possible. The result: beasts of burden.

If they are in the move, they need wheels and carts soon to carry more than a single person can (they could develop sledges, too). Perhaps they follow the path of the big herds because they make the terrain flatter and the manure can be used for many things (they could even eat some things they can't digest themselves unless they have suffered the stomach acids of the herd animals).

People riding carts and wagons can use their time for developing more complex things like the loom.

Perhaps they could use the herds for everything: their bones and teeth in substitution of strong metals they can't harvest.

With all those things, you only need a surplus of food to get tribe leaders, priests and artisans, the start of civilization.

I don't know how they could get that surplus, though.

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    $\begingroup$ Scythians describe the nomadic pastoralists of Central Asia. Cultures who follow this lifestyle existed all the way up through the Mongols. As noted they invented horse riding, and the cart. They had a rich culture. They built durable structures too; "kurgans" in which esteemed dead were buried. Although the Greeks did not consider them civilized. $\endgroup$ – Willk Sep 11 '17 at 12:16
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    $\begingroup$ The beasts could get large enough to build houses on maybe even cities if they are large enough. $\endgroup$ – Totumus Maximus Sep 12 '17 at 7:53
  • $\begingroup$ @TotumusMaximus For cities they should be massive! $\endgroup$ – Alberto Yagos Sep 12 '17 at 9:04
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    $\begingroup$ @AlbertoYagos It might be a good reason for them to be nomadic then. Though resilient it must find food and water to survive. You probably won't find much food and water after such a massive creature stays in one place for a while. $\endgroup$ – Totumus Maximus Sep 12 '17 at 9:28
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    $\begingroup$ @AlbertoYagos I can't stop thinking at the novel Mortal Engines (the cities became giant moving machines and started predating smaller and/or broken cities for materials) $\endgroup$ – frarugi87 Sep 12 '17 at 15:56

In caves, protected from sun and cold. Possibly carved out by a meltwater river during the days. A couple of days, a generation, to learn how to live without moving and time to expand the cave system into something more suited to habitation. Maybe they got lucky and found metals and coal in the cave.

It would have to happen many times, rumours that it was possible to survive the day in a cave if you were too injured to outrun the dawn. A story that someone once survived the night in a cave with a hot spring. Tribes in dire need of a safe place forced to take the risk. Some live, some die, one thrives.

  • $\begingroup$ I'm not interested in working on such a world currently so I will not bother too much with it, but I like this idea because it leads to a bunch of other interesting problems, for example: Will they be able to breathe while living in a cave during eternal night and a very hot day? Where does that oxygen come from? What about the meltwater you spoke of in the spring? ... $\endgroup$ – Raditz_35 Sep 11 '17 at 9:22
  • $\begingroup$ @Raditz_35, meltwater floods while trapped underground are going to be fun, they'll have to be very lucky to survive the first time. I think worrying about hot/cold air above basic ventilation would detract from the telling of a story. $\endgroup$ – Separatrix Sep 11 '17 at 9:31
  • $\begingroup$ Coal mines could make people want to range out from the poles, spending a night in the coal-warmed mines of Moria ;) and travelling back and forth to the pole during the day. Near the poles would be easier, of course. $\endgroup$ – JollyJoker Sep 11 '17 at 11:26
  • $\begingroup$ That raises a thought, what about other extreme sources of temperature? Smoldering coal-veins, volcanic activity, etc. for the long night, the remnants of glacial caps for the long day? * brain stutters * high-tech underwater cities... $\endgroup$ – G Allis Sep 11 '17 at 22:28
  • $\begingroup$ @GAllis I'd imagine those would be an oasis in the otherwise deadly noon/night sides $\endgroup$ – TrEs-2b Sep 11 '17 at 23:44

It would be a really long circuit in this case but a lot of the ancient hunter-gather/herding nomads used to follow an "annual round" of the same sites at the same stage of the season year on year. This creates a reasonably reliable, stable resource budget for the group allowing for some leisure at certain stages of the trip around so that they can work on non-essentials, the trappings of a "material culture" that we would start to recognise. This only really works when there is a level of dependable resource repetition i.e. what was here last year, yesterday in this case, is there again this year. Many herding cultures move/moved with their animals constantly but have/had very advanced material culture and reasonable levels of technology up to and including the working of Iron so there is a precedent.


Several people have commented on how food surplus is the key factor. Let's take this a step further and say that specialists are what you need for civilization (smiths, philosophers, artists, potters). That is, you need enough surplus food that you can afford to have people not busy in food production, be it farming or herding.

So to solve your problem you can either make herding more productive (fast growing animals; plants explode into bloom when the "good zone" passes over them), or posit that local flora, including wheat analogues, are clever enough to drop seeds which then wait for the next cycle. You can have time-lapse farming, though your timing has to be good to end up with your own fields the next year. (Plenty of opportunity for conflict there, mind)

Failing that, you can have civilized ideas, techniques and goods spread from the poles. You have a rough mapping of latitude to civilization level, where extreme North/South tribes are pretty civilized, but equatorial tribes are howling savages. Makes for good quest fodder -- "You must travel through the wild lands to the opposite pole to retrieve the Holy MacGuffin"


Migratory people will start off as hunter/harvester, like we did on Earth. But...

On Earth we had the issue of gathering enough food, and as Jimmery pointed out, rivers were an excellent answer to the need of harvesting enough food.

But your people live in perpetual motion around the globe to chase the light zone. Same will do also plants and animals. In particular the plants will tune their life cycle to the day/night, so that they grow fruits and produce seed during the day.

If you set the migration speed to the proper value, you can be sure to always reach a place where ripe fruits are present and you don't need to worry about harvesting in scarcity. Over generation you can even build up memories of best locations, and plan the migration accordingly.

Now, with such a bonanza, why would you need "civilization"? Just migrate, harvest, eat, sleep, repeat. And mate in between.


Other answers suggested mobile plants, like the "tumblewheat". This would work especially well on the dusk side due to the wind, which conveniently is where people initially evolved.

Said wind would probably be constant and very strong, from the night side to the day side. On the day side, air is heated, creating a low pressure zone. The cold, high pressure air of the night side rushes in, creating the wind. Night air is renewed by opposite winds at high altitude from day to night side, creating a giant convection cell. (This is assuming that air doesn't freeze on the night side, which would slightly complicate things.)

Dusk wind would help plants and animals to move with it, and humans could tap it for movement as well. They could use wind-propelled animals and sailing crafts. This also means that dusk would extend further toward day with the cold wind compensating the hot ground. The temperature difference, which may be considerable at reasonable depth in some places, could be used by fast-growing plants in addition to sunlight. Those plants would probably have a seed or dormant state that can survive extreme heat and cold, with an explosive growth at dusk, and possibly dawn. They could be harvested by the migrants, and even cultivated by planting the seeds for the next passage.

This may give them the necessary surplus for developing a civilisation. If they use fast-growing plants, it will have major impacts on their worldviews. Expect them to be long-term planners.

Polar cities could use those constant winds for industry with windmills, and even for observation with semi-permanent crewed kites. Migrants could also use lighter versions of those, but they would have to be either mobile, fast-disassembled or fast to build for one-time-use. For polar cities to be viable, axial tilt is probably very small, and even then they may have inactive periods when people lock themselves up to escape the near-unbearable heat and cold.

Dawn dwellers may have a harder time, as wind is on the wrong side. If advanced enough, or if animals or plants evolved it, they can use tacking to sail in the right direction. The existence of dawn dwellers may have serious impact to the dusk civilisations, as they could both help fast-growing plants agriculture and hinder it by feeding on them without replanting. This could destroy a dusk civilisation, but also the foolish dawn dwellers as there will be nothing to eat on the next passage.

Being migrants doesn't prevent them to build permanent structures, though. The most obvious ones are roads, flattening the ground so the next passage is easier. Reshaping the ground for easing agriculture or herding is also a possibility, as well as ground foundations, even walls and other erect structures that would only have to be minimally completed with temporary materials for usable buildings. Again, dawn dwellers could have an impact. Maybe this is even why dawn was settled, to help dusk civilisations for agriculture and to build faster per cycle.


You're conflating "civilisation" and "buildings". The two aren't necessarily connected. Most obviously, Genghiz Khan came from a tribe of nomadic herdsmen, and managed to construct a continent-wide empire. Not only that, his empire was governed by rule of law in a way which other European countries of the time were conspicuously lacking.

"Civilisation" simply requires philosophy, debate, a way to record the results, and a formal system of norms by which citizens are expected to live.

The main thing agriculture provided was population density. It's much easier for farmers to live together in large groups than hunters, and the more people you've got, the better the discussions are going to be. It's not the only solution to this problem though - fishing is another popular way to feed your population, for instance. Or as with nomadic tribes on the Steppes, or Europeans practising transhumance, you can domesticate livestock and move with them to new grazing sites.

There are plenty of options which don't need agriculture.

  • $\begingroup$ I'm not sure that the Mongol Empire would have been possible had the various peoples they conquered been nomadic. (It should perhaps also be noted that the word "civilization" derives from the Latin word for "city", but not taken too seriously.) $\endgroup$ – Harry Johnston Sep 12 '17 at 3:33
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    $\begingroup$ @HarryJohnston You're right about the origin of "civilisation", of course, but also consider that the Latin for "savage" ("homo indominitus") literally meant "a man who won't be beaten". Sometimes language tells you stuff about cultural preconceptions. :) As for the Mongol Empire, it was all about the trade routes, so I don't see there would have been a big issue with the people along the way being at least somewhat migratory. It's an interesting "what-if", anyway. $\endgroup$ – Graham Sep 12 '17 at 11:42
  • $\begingroup$ Surely the trade routes in question only existed because of the cities at either end? Nomadic cultures do carry out trade, of course, but I wouldn't have thought it was ever large-scale enough to have supported a major empire. (This is most definitely not my field of expertise, I may well be wrong.) As you say, it is an interesting what-if, but perhaps it needs to be fleshed out a bit more. $\endgroup$ – Harry Johnston Sep 12 '17 at 22:50
  • $\begingroup$ @HarryJohnston Not exactly my area of expertise either. But the trade routes weren't so much between cities as between trading centres. Medieval fairs were about local traders and cross-country traders all pitching tents in the same place for a few days, then all heading home again. Usually they happened near a town, but they vastly outnumbered the host and basically became their own town for those few days. Nomads could easily meet at a particular fixed place for a few days, then wander off again. $\endgroup$ – Graham Sep 22 '17 at 10:11

Another point that you haven't taken in account is vegetation, which would need to find a way to survive scorching summers during 4.5 years and extremely low temperatures during the other side, which would make any form of vegetation and animal life extremely scarce and limited to extremophile single-celled organisms, any form of plant and animal evolution would either have to happen deep underwater, or, as you said, to exist in the poles, where there is a stable temperature year-round (not accounting for the axial tilt, which could cause some problems depending on its angle)

Most of the scenarios that deal with intelligent life that always must be in the dusk/dawn to avoid being fried/frozen exist in planets tidally locked to their star, this way, there is a ring where the temperature is constant throughout a 'very long time' and life can evolve as it normally would, but in your scenario i find that the only form of plant life that could survive year round is some sort of fast growing shrub, fungi or grass that spreads quickly, but if there is any continental separation that could be another problem, as the plant wouldn't be able to spread from one side to the other, that brings us back again, making so that any form of life would need to develop deep underwater, where temperatures would be constant during summer and winter due to the thermal protection given by water.

But, as explored by our other reviewers, human civilization arose from the fact that we went from nomadism to sedentarism, our modern civilization only exists due to the fact that we stopped moving, so for a large civilization to arise in such a planet, discarding the effects of its particular day cycle, they would either have to find some way to survive on the poles, find a form to survive deep underground for years until dawn/dusk comes (which is highly unlikely) or only exist in large nomadic tribes which developed a more efficient method of organization to make sure the tribe is well fed and alive and always in the move, but you already specified that that is about how they live.


Writing seems to have been developed, far as I can see, by traders. Travelers, moving from place to place to buy and sell things - including non-physical things like skills and techniques and training and news... and trainees, skilled artisans, marriage partners, and slaves who bore those in their heads and spread those knowledges.

So writing and numeracy, which I'd say is ultimately core to any civilization, can be created by people who need to travel constantly.

If you're moving, you need to keep track of things. Quantities of things. You want to make a living profit, so you need to keep track of prices and how much you have of stuff, and where you sold things, and what you earned, and also metadata like "butter up the headman of this area for better profits", and "this guy owes us for last time".

Note that this is for people moving relative to other people, but I think in a continuously-migratory people, that would be quite common: they wouldn't clump together so fiercely, since they already have the means to move back and forth.

Most stories of this type tend to have a "habitable layer", between the melting day side and the frozen night side, essentially making civilization one-dimensional: each tribe or culture rules a stretch of the habitable zone.

You can also slice it the other way, into subcultures that handle the different heats - seeder specialists plant the crops on the leading edge, harvesters take the trailing edge, and trade happens between the two.

Winds would constantly flow from night to day.

The day-to-night edge would have different culture and harvesting approaches to the night-to-day edge. In one, the harvesters would forever be in the chill twilight, harvesting tumblewheat that rolls towards them with the wind; in the other they would forever be retreating from the baking sun, chasing the tumblewheat. They may not even be needed, as the tumblewheat will roll back towards the seeders on its own.


Tumblewheat and plant life with seeds that can survive long hibernations are excellent ideas to begin with. The prevailing winds due to the convection cell inspired me to consider travel by wind power.

What if someone had the brilliant idea to create a hot air balloon equivalent, and then build large mobile platforms suspended beneath them?

Parts of the platforms could be covered in fertile soil for farming which would produce high yields due to the "explosively blooming" nature of the dormant seedpod plant life which would now always exist in the habitable zone.

The platforms themselves could be steered by sails and slowed down if necessary by stone anchors since gathering metals would be nearly impossible without finding some kind of deposit on the surface.

The balloons could be powered by some form of natural gas that rises from cracks in the planet's surface. The people should have mapped out these "wells" of natural gas and steer their platforms from well to well similar to caravans traveling between oasis' in the desert.

This could introduce some interesting conflicts when a well dries up, or a new, more advantageously positioned one opens.

  • $\begingroup$ Welcome to WorldBuilding! Interesting first answer. If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Sec SE - clear Monica's name Sep 11 '17 at 19:42

Orbital Mechanics:

In 2 body systems, bodies tend towards rotation rates that match the period of orbit because of the way that their respective potentials are shaped. We call this tidal locking. Because stars are much bigger than planets, the planet's rotation slows (usually).

What that means for your world is twofold: such a system may not be in equilibrium, and the planet may shortly become locked: dayside and night side forever. If you don't want that, I recommend a very large planet and moon(s), or a somewhat close-by planet whose orbit has a curious integer relationship with 9-years world.

The second thing to consider is that the planet (especially one without a moon and maybe smaller) was not always so long-dayed. Civilization could have emerged in an earlier time and continued through the planetary changes that led to 9 year days.

Within the premise of your question:

Civilization requires a surplus of calories. Humans first got this by cooking our food, and second by agriculture. Either could happen and be explained relatively easily. There is an abundance of game while chasing dawn/dusk (and with the advent of cooking/food preservation, more calories) and the denizens could leapfrog: plant at dawn, wait for crop, harvest, move on to dawn (or plant in the evening, wait for dusk and harvest in the twilight of the evening before moving back into the heat of the day).

The next requirement is tools which either need to be made in camp, or in bases which the populace moves from and to at intervals as they chase the dawn or dusk. A mobile populace actually has an easier time with this because they will see a planet's worth of geology in their migration, and can set up shop near to mineral resources.

No group thrives without specialization - the genesis of trading. Since there are people on the poles in perpetual twilight, it's possible that both civilizations cannot survive without each other - the polar people need something they can't get from the poles (a type of food, salt, tools, metals, etc...) and that the nomads can't get in their travels (food, salt, technology that's only really possible for people who can stay in one place, etc...).

Civilizations needn't develop independently - mutual benefit is the basis of civilization, and you have set up 3 very clear societies which could benefit greatly from trade, and who might never thrive without it.


I got kinda inspired by many answers here, particularly the Jimmery and L.Dutch's.

A note I will quickly state that there is a strong question 'how do we define civilisation' here. The process of progress in life of humanity started long before homo sapiens was born, not to mention starting agriculture. It started when homo habilis made his first tool. It started even earlier, when whichever homo it was (cant recall) organized his fellows for a first time with speech. I will try to keep to the spirit of Your question the best I can, but please keep this general thought in mind.

1. In my head, some nomads caught on the idea that if they do some field work on the area in which they are at a given moment, on the next year when they pass on that same area it will have more food for them.

2. More food is good, so they slowly started to get rid of plants they don't need, planting the seeds of the plants they like, building some protection against the elements for them. This lead to some minor improvement for them, so the next thing they needed was to always return to the gardens they set up along the way. This forced them to develop geography and navigation, so astronomy, mathematics and eventually writing system for those. Btw their life was harsh and difficult, so I expect codified laws rose pretty quickly and independently in many tribes.

3. Many tribes = many conflicts. Conflicts over naturally rich in food valleys, best hunting spots, rivers richest in fish. Warfare was, historically, the best motor for human development, and probably so it was here. Weapons is one thing, but organisation is another - discipline and communication are a difference between life and death in war. So the conflicts were another motor that driven the development of mobile civilisations.

4. Conflicts and gardens cultivated along the way brought another point. If i cultivated this garden last year, I want to eat from it now. If someone gets to it before me and plunders it's richers, I'm going to be angry. VERY angry. I'm going to build a fortifications around it and next year I'm going to sent in front of me a quick, mobile force with temporary sun and heat shielding so that i am sure that this force gets to the fortress and the garden FIRST and protects it until my main caravan gets there.

5. One of the great questions with this world which pops into my mind is oceans. It's impossible to travel around the earth only on foot. Maybe continents on Your planet are places in such a way that this is possible - but if there are any choke points, I would use them to block the passage for those I don't like for as long as I can, so that they die in the nightwinter behind me - again I would need a mobile force which can hold as long as its possible and then very quickly rejoin the caravan.

6. The oceans bring another point. The first one to master sailing across them gets an enormous strategical advantage. Building ocean worthy ships quickly is tricky, but may be possible - starting with just traveling along the coast maybe (because, You know, big bad tribe is blocking the land passage out of spite), but in the end creating design of vessel which can be built quickly each year, either in great numbers or great scale (massive raft-island?) and is ocean capable.

7. Far into the future, I see Your species advancing technologically to the point they may even have steam or nuclear powered walking cities - still travelling around the planets after millenia, tough perhaps needlessly at this point. But old habits die hard, we, on earth, still keep traditions which have been rendered obsolete generations ago.

On the other hand Poles? Subpolar regions? I don't think I need to elaborate, with right geography they could provide a very interesting alternative avenue for travelling all year round.


Just like on earth. You migrate to far and in such number that you end in Rome or conquering a almost all Asia and part of Europe.

Another thing is how you define civilisation. Remember that the nomadic Jews created a whole book about the magic things that happen when you travel. The rules that are written in there are used to this day.

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    $\begingroup$ 240 miles in 40 years doesn't really count as nomadic $\endgroup$ – Separatrix Sep 11 '17 at 7:50
  • $\begingroup$ If you are talking about the Exodus, then a) there is no archeological evidence of it, rather there is a bunch of evidence against it en.wikipedia.org/wiki/The_Exodus#Historicity and b) even by the Exodus account, they did not start their civilization during the Exodus but were already a civilized people, so it not a good example for the OP question. $\endgroup$ – SJuan76 Sep 11 '17 at 7:52
  • $\begingroup$ @Separatrix You didn't read the book. They were nomadic from the expulsion from Eden. But in seriousness Old Testament is a pocket guide to be nomadic. Not having pork is a staple of such life. $\endgroup$ – SZCZERZO KŁY Sep 11 '17 at 7:57
  • $\begingroup$ @SJuan76 As you mentioned, they were civilized people before. And Old testament is a book about being nomadic and having a civilization. $\endgroup$ – SZCZERZO KŁY Sep 11 '17 at 7:59
  • $\begingroup$ @Separatrix, who said they went straight to the point. All we know that they were wandering in the desert for 40 years, and undefined time before Jacob's family moved into Egypt. $\endgroup$ – user28434 Sep 11 '17 at 8:57

Perhaps the civilization didn't actually evolve on that planet to begin with. You could maybe be dealing with a shipwrecked civilization that has had to adapt to this environment. It's kind of a bit of a trope but it does allow you to hand-wave away the need for the civilization to develop over time.


Perhaps the planet wasn't always this way. Perhaps the days are only 9 years long now but in the past they were much much shorter. A 9 year long day would require that the planet is almost tidally locked with it's star (but not quite as it would need to slowly rotate in opposition to its orbit.

This would be a peculiar orbit so it's interesting to think about how that might have happened. One possibility is that a large rouge gas giant planet passed through the solar system and disrupted the orbit and rotation. Another idea is that some disruption such as the rogue gas giant moved a small rocky planetoid into an orbit around the planet such that the it slowed the planet down.

Another idea is that perhaps the planet was originally in a pole oriented orbit with one pole tidally locked. The civilization could have thrived in the thin strip between the dark and light side. Then at some point a cataclysmic shift occurred (again because of external gravitational forces or even an impact) that shifted the entire orientation of the planet.


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