Designing a Sky World

[Davian]

EDIT: I do intend for this thread to move in the direction of this forum section's intended purpose, so I apologize if the initial post possibly falls a bit outside the lines, and I'll gladly adjust as necessary. Wasn't 100% certain.

I'll admit that for a long time, I've been a sucker for fiction revolving around the whole "sky pirate" motif, as seen in games like Crimson Skies. They're often filled with colorful characters, cool diesel-punk technology, and exciting adventures. Often, they take inspiration from the whole 1920s pulp aesthetic. And some works, like Skies of Arcadia, go even further by placing the whole thing in a fantasy "sky world", where islands and continents float among a sea of clouds, and aircraft serve in place of naval vessels.

But obviously... Such worlds require a *huge* amount of suspension of disbelief on the part of the audience. And to be clear, that is 100% fine in my book. Often, the setting gets away with it through the pure charisma of its characters and aesthetics.

Still, I've been working on a little project, and thought it would be fun to try my hand at designing a setting in this vein. Basic ecology, geology, etc and then extrapolating the social and economic factors that would shape human society in such an environment. The audience obviously doesn't need to know every detail at play under the surface; over-explanation can easily get in the way of good storytelling. But I think laying out some ground rules for my own reference could provide a lot of fertile ground for interesting scenarios.

I've already thought a lot about it and written down my ideas, and I'll put together another post that lays out the very basics if people are curious. And if the conversation takes root, I'll gladly share more too.

But to start, I'm just curious as to whether anyone can recommend any good references of settings that have attempted to apply rules to such a blatantly ridiculous concept. Any feelings on what was done well or poorly in that regard, or thoughts on what would make such a setting more or less compelling to you?

[JeenLeen]

There's a Playstation video game called Granstream Saga (wikipedia link). It took place between floating continents. A big thrust of the plot was that the <whatever> that was keeping the islands afloat is failing, so they'd occasionally have to cut away part of the land to keep the rest afloat.

I forget the details of the metaphysics or how well the game went into it, but it was a pretty cool game and setting. You might find some inspiration.

[Tvtyrant]

I think the best version I saw was one where the islands were held up by electromagnetic leylines, which when they intersected made nodes. The soil on the islands is a kind of iron sand held to the nodes by magnetism, and iron steam ships move along the leylines between between the islands.

So the leylines make stable shipping routes, but to go outside of them people use none-ferous dirigibles (removing iron from the leyline system is nearly impossible.) This meant pirates and smugglers used wood airships, the main powers and merchants used iron ships.

I forgot what the name of the setting it, sorry.

[JeenLeen]

Thinking on this some more, I think I came up with a somewhat reasonable magi-tech way to design such a world.

Basis: due to <some catastrophe>, the ground is no longer safe for habitation. Monsters, pollution, radiation, whatever. So, before it got too dangerous, power wizards either created or levitated chunks of ground into the air and set up portals to help stabilize them such that they can continue to exist as stable environs even if the wizards die out.

On the bottom of each floating island are several portals to the Elemental Plane of Air. Fast air pushes out of the portals, creating lift akin to a rocket. The portals are created such (or keyed to areas of appropriate air pressure) that they mostly keep the island stable. This could let the island drift, either randomly or in a trackable pattern, depending on desire of the setting.
Alternative: portal to the Realm of Fire for streams of fire like literal rockets holding the islands afloat.

On some mount near the top of each island, there is a portal to the Elemental Plane of Water. This provides a river that gives fresh drinking water.
Alternative: it gives salt water, but folk are used to evaporating the water to make drinking water. Large and wild animal life is somewhat scarce as rain is the only source of freshwater for wildlife.
Alternative 2: perhaps rain water is toxic due to whatever catastrophe caused folk to flee to the air, so this 'portal water' is the only clean source of water. (Rain water shouldn't be so toxic that it ruins crops or kills by touch, but perhaps enough to sicken if drunk or ruin crops if overly exposed. Thus, perhaps there are many coverings used to guard crops and protect livestock.) But that might be more trouble than it's worth to explain, since usually rain water is clean of toxins due to evaporation, and presumably the islands are high enough that the rain wouldn't absorb it from falling through the sky to the islands.

Something about a majestic green island, with a waterfall coming out of a portal running down a river into a lush valley and medieval village, with violent and large bursts of flame underneath really appeals to me as a cool juxtaposition

Environmental thoughts: people can maintain crops and livestock. I could see a tendency to smaller animals that give lots of offspring, like chickens, as opposed to things like cows. Animals that don't spook easy could also matter: you don't want your herd of sheep panicking and rushing off the edge of the island.
Wildlife could be whatever could be supported on the size of the island, as people from the ground could have carried some up there. Though most islands probably only have animals that people cared to take with them (or that tagged along, like rats or roaches), I reckon some would have a variety of natural life as some people cared to try to preserve nature. Birds are probably common and versions of birds might replace wildlife.

Trade: if the islands are stable or follow a fixed pattern, folk could know how to get to other islands (or when they are floating near one) and trade appropriately. I could see magitech ships using smaller versions of the portals for levitation. Or (as is probably better) if that tech is lost, perhaps trade is done by gliders: climb to the top of a peak and glide to the lowland of a nearby island. Depends on how easy you want to make travel between islands.
If island flow erratically, then meeting a new island is probably a tense thing. Great chance to trade news or for rare goods, but maybe they're hostile?
Perhaps some birds tend to fly away from islands, and whether or not they return by nightfall is a good indicator if an island is nearby. An order of Birdwatchers could be an island's military and/or merchants, using them as cues for when to be ready for whatever may come.

[DeTess]

The core setting of the Warbirds TTRPG uses the skyworld concept. The system as a whole might be a good thing for you to look at, as it includes everything else you'd need to run a sky pirate game as well.

Anyway, for settings like this, I think it's better to just ask the players to suspend their disbelief regarding floating islands than to try and cook up a pseudo-science explanation, as such an explanation can easily be torn down by someone feeling contrarian. If you do want some sort of explanation, make sure that you've thought through its consequences. If you've decided that the islands float because of a big crystal in its center, expect the players to try to sink an island at one point or another by blowing up that crystal, of if there's some kind of material in the ground keeping the islands up, expect a player to ask what would happen if that material got mined. If you're ready to deal with these questions than going more in-depth on why the islands float could be nice, but imho its fine to just say that the islands float,a s long as that's the only big suspension of disbelief I have to do for the setting.

[Mechalich]

A question I think is important for designing such a world is whether or not you want there to be ground at all. Meaning, to the sky islands float in clouds that descend potentially forever, or is there some distinct ground layer below that can be seen by everyone and potentially even visited it just happens to be a largely uninhabitable wasteland. This makes a difference, especially if the ground is accessible enough to mine for resources.

Also, in terms of being more believable, you can say that your world of sky islands is set within the life zone of a gas giant. It's not impossible for a segment of atmosphere with a fairly traditional oxygen-nitrogen mix to exist within such an environment. Then your islands represent a substrate that accretes into being around massive organisms of some kind, like giant floating reefs, complete with sub-surface buoyancy bladders that keep them suspended at a viable height. If your reef structure builds downward to chemically rich lower layers, then the surface might be a hardened layer of silicate-based rock thousands or even millions of years old and could develop it's own surface ecology along more traditional earth-like lines. You could even mine the oldest floating islands for oil or coal in such a scenario.

In terms of generalized play structures, the cloud islands scenario, regardless of the specific construction, is less like a scenario with islands in an ocean, and more like isolated oasis settlements in a desert, because empty air is much more of an obstacle like barren desert compared to a life-filled ocean. Additionally, unless you have some sort of abundant lighter-than-air gas resource or other way to provide bulk transport without using resource-hungry engines, resource scarcity is going to be a rule in your setting in the same way it would in a desert one.

[Max_Killjoy]

If you want to go full-on not-in-Kansas skyworld, you might look at Larry Niven's The Smoke Ring and The Integral Trees for some inspiration.

[Wizard_Lizard]

Have you read the edge chronicles?
That has sky pirates.
Thy use rocks to fly!

[shawnhcorey]

I don't know why people feel they have to come up with a "scientific" explanation for their fantasy world. The best stories are defined by their characters. Their aesthetics are just a bonus. If you want characters living on the clouds and mining rainbows for their gold, go ahead. Let your players comes up with reasons if they want to but you don't need to worry about it.

[Tvtyrant]

I don't know why people feel they have to come up with a "scientific" explanation for their fantasy world. The best stories are defined by their characters. Their aesthetics are just a bonus. If you want characters living on the clouds and mining rainbows for their gold, go ahead. Let your players comes up with reasons if they want to but you don't need to worry about it.

It isn't science per say, having rules just makes it easier to maintain coherency. If there are no rules then any exploit feels like fiat instead of cleverness, and you can't know ahead of time if a plan will work.

People like rules, it is inherent to our natures to look for rules and patterns.

[noob]

Simplest sky worlds: gravity diminish with range much more(maybe cube of range instead of square of range?) and none of the life forms evolved around air and there is no air so people can go from one planet to the other with rockets much easier (since you get out of the attraction of a planet much easier).
Maybe by calculating right the force of gravity and adding a force of repulsion that have a lower dropoff speed but a lower starting strength you can even have clumps forming but not getting over a given size and clumps near the size where the force of repulsion is strong enough to start tearing parts off are easier to escape if you are on the borders of the clumps. (With the right values you could have people jumping from one clump to the other)
I mean why do everybody wants lifeforms to need air and then make complex explanations on air: skyworlds are easier to make without air.

[JNAProductions]

I think the best version I saw was one where the islands were held up by electromagnetic leylines, which when they intersected made nodes. The soil on the islands is a kind of iron sand held to the nodes by magnetism, and iron steam ships move along the leylines between between the islands.

So the leylines make stable shipping routes, but to go outside of them people use none-ferous dirigibles (removing iron from the leyline system is nearly impossible.) This meant pirates and smugglers used wood airships, the main powers and merchants used iron ships.

I forgot what the name of the setting it, sorry.

This sounds very interesting.

[Palanan]

Originally Posted by Max_Killjoy
If you want to go full-on not-in-Kansas skyworld, you might look at Larry Niven's The Smoke Ring and The Integral Trees for some inspiration.

In addition to these, check out Endymion by Dan Simmons. He has a superb description of the oxy-nitro layer of a gas giant, as seen from the perspective of someone sailing through the clouds in a flying kayak.

Sounds wacky—and it is—but he makes it work and then some.

We just won't talk about the radiation hazard.

[DeTess]

Simplest sky worlds: gravity diminish with range much more(maybe cube of range instead of square of range?) and none of the life forms evolved around air and there is no air so people can go from one planet to the other with rockets much easier (since you get out of the attraction of a planet much easier).
Maybe by calculating right the force of gravity and adding a force of repulsion that have a lower dropoff speed but a lower starting strength you can even have clumps forming but not getting over a given size and clumps near the size where the force of repulsion is strong enough to start tearing parts off are easier to escape if you are on the borders of the clumps. (With the right values you could have people jumping from one clump to the other)
I mean why do everybody wants lifeforms to need air and then make complex explanations on air: skyworlds are easier to make without air.

The reason people assume air is that things become really weird if you assume there's no air, requiring handwaving on the same level or higher as 'there's air around my skyworld chunks of rock' to keep a workable setting. Without air, projectiles aren't slowed down and communication is impossible. Weather is no longer a thing and water immediately evaporates, so the people in your world also can't need water, nor anything else that needs water (like plants). I'm certain there's a whole bunch of other things that'll go wrong without air,but these should give you an idea.

[noob]

The reason people assume air is that things become really weird if you assume there's no air, requiring handwaving on the same level or higher as 'there's air around my skyworld chunks of rock' to keep a workable setting. Without air, projectiles aren't slowed down and communication is impossible. Weather is no longer a thing and water immediately evaporates, so the people in your world also can't need water, nor anything else that needs water (like plants). I'm certain there's a whole bunch of other things that'll go wrong without air,but these should give you an idea.

So you are saying there is no ice asteroids?(easy source of water you just need a combustion reaction to reheat so you could have living stuff that feeds on combustibles and water)
Also projectiles not being slowed down is not a problem(it just means it zooms in space until it collides with something or slows down enough due to gravity or the repulsion force(although those two things can also speed up the projectile depending on cases)) and communication is 100% possible with light (you could have most creatures use bioluminescence) and who cares about weather?
Of course stars might be not possible with the rules I indicated(unless fusion rules are changed but then it would give other problems) but with gravity that diminish more firmly over distance maybe black holes would radiate faster(we would need the exact calculations to see if it is meaningful)
and black hole radiation might provide the world with the heavier elements(stuff beyond hydrogen) that is needed for making lifeforms.

Furthermore it is not air that creates weather on its own so on your skyworld you need one handwave for air then one for weather that is a separate handwave because there is not the kind of phenomenons that could create wind(a combination of the rotation of the thing on which air is and of the fact the air stays close to the thing thanks to gravity in the case of earth) and the varied elements of weather.(clouds for example)

[DeTess]

So you are saying there is no ice asteroids?(easy source of water you just need a combustion reaction to reheat so you could have living stuff that feeds on combustibles and water)
Also projectiles not being slowed down is not a problem(it just means it zooms in space until it collides with something or slows down enough due to gravity or the repulsion force(although those two things can also speed up the projectile depending on cases)) and communication is 100% possible with light (you could have most creatures use bioluminescence) and who cares about weather?
Of course stars might be not possible with the rules I indicated(unless fusion rules are changed but then it would give other problems) but with gravity that diminish more firmly over distance maybe black holes would radiate faster(we would need the exact calculations to see if it is meaningful)

A combustion reaction requires oxygen, which is not plentifully available in a world without air. There's also the temperature problem, as without an atmosphere to trap heat it'd generally be very, very cold.

Then there's the problem of food. Even the simplest plants need nore than water to exist.

What you're trying to do isn't impossible, but the resulting setting has just as many, if not more, departures from reality than just accepting a skyworld with atmosphere, and that setting is at least recognizable to the players. The atmosphere-less setting as you describe it would continually run into mundane issues like 'can I whisper with bioluminessence?'

[Davian]

(PLACEHOLDER: Hey, wow! This blew up more than I expected. Sorry that stuff came up IRL, but I'm going to go back and read over everyone's input! I'll edit this post once I get my thoughts in order.)