Interesting Geographies - Worlds that are not planets

[brian 333]

In one of my adventures I took a page from The Bible and had my seafaring adventurers eaten by a sea monster of immense size. Once inside they discovered a group of scrags living within who had never see of the outside, and who viewed the periodic washes of food-filled water as blessings of their god.

Of course, they also wanted to eat the adventurers. Let's just say it got messy after that.

However, a society which evolved within the belly of an immense beast is limited only by the size of the beast and its basic chemistry. An air-bladder in a giant fish might be a suitable habitat if access to food is available, or the first of a series of stomaches. If the creature is large enough it may even appear to be a world of some sort. What happens to the inhabitants when the world-fish decides to swim away from the home-star to seek out other opportunities?

[Illogictree]

I've enjoyed creating some strange settings myself, probably inspired by my reading Weiss' Death Gate Cycle back when I was a kid. Some of these were intended as settings for RPGs, some not. I don't really have any names for them, either.

The first, and probably most boring by the OP's standards, was the Pathfinder-based flying islands/continents setting. In this case, the islands are floating over a vast flat land similar to the 'infinite' planes of DnD. The islands drift, or more accurately orbit, across the lands according to regular patterns, bringing different lands nearer and farther apart. The twist to the setting was that the flat land was neither flat nor infinite - it was simply another super-gigantic, convex island, the shape implying that the setting was the shattered remains of a Dyson sphere. The exterior side was the "light" side, illuminated by an orbiting star and inhabited by humans, elves, halflings, mythology-based monsters, etc. The interior "dark"side had its own gravity oriented in the opposite direction and the sky was illuminated by the massive negative space wedgie that probably used to be inside the Dyson sphere, and its weird gravity fields were the cause of the strange gravity and floating islands. This dark side was inhabited by the drow, fetchlings, duergar, wayang, aberrations and other weird fantasy monsters, etc.

Another setting was partially inspired by the world of Chelestra in the aforementioned Death Gate Cycle and also dictated by the needs of the sorts of action I wanted in the setting. In this case, it took place in space, with the inhabitants living in vast caverns within the shells of gigantic living creatures called shell-worlds. These shell-worlds lived in a huge pod that followed a star through its travels around the galaxy, feeding off its energy and living in symbiosis with the creatures living in their shells. Their shells themselves were many kilometers thick and riddled with roughly spherical bubbles, from as small as a pinhead up to kilometers in diameter. Several intersect, forming a complex of caverns. Some of the larger ones intersect the exterior of the shell and are actually open to space. An 'anti-gravity' force emits from the shell-world, pushing objects away from it, and a sort of 'integrity field' keeps air and water inside the shell-world. The shell-world grows light- and heat-emitting organs into the ceiling of the larger bubbles (or grottoes, as the inhabitants call them). The upshot of this was that there were large habitable areas inside the shells such that several had central 'pools' that lead outside into space, giving a convenient area for space vessels to enter and leave by.

I think that's probably enough for now, since those were rather wordy.

[SirKazum]

I've been playing around in my head with a few different ideas for campaign settings that try out different shapes and such. One of them is the "Spheres" setting, where all known land is located in a series of spheres (more like bubbles). There's a single definite "down" direction (at least from each sphere's point of view), so you have earth accumulated on the bottom and air above. The spheres themselves are clear and transparent, and also unbreakable by any means anyone has ever tried - maybe they're force fields? Anyway, the idea is that each sphere (which can range from a couple miles across to several hundred miles across) has a single type of climate and terrain - for example, you have a forest sphere, a desert sphere, an icy sphere, and so on. Not all of them have solid land - one sphere might be completely filled with water, another with half water and half air (just a huge ocean), another just air (and home to flying creatures), another completely filled with earth and with creatures living in caverns, and so on. Those spheres are all linked to one another through portals, which work in varying ways - some portals are permanently open, others open periodically in a predictable manner, others are unpredictable, and some open only when a specific "key" (an action or an item) is present. The idea is to have a bunch of different cultures and ecosystems interacting with one another through the portal network. The whole setting was obviously built by intelligent beings - not just due to its strange premise, but there are also clues left behind such as buildings, inscriptions etc. - which take action to prevent the rise of mortal beings powerful enough to jeopardize the structure of the spheres, or also figure out what's the secret behind them. Unbeknownst to everyone, the crochety old man who runs a ratty little tavern in a sphere-wide city is a former Builder, exiled for unknown reasons...

Another idea I like is a world that's folded onto itself along the fourth dimension, similar to a hypercube or a hyphersphere. To visualize how that would work in practice, imagine the world looks flat from its surface, i.e. you see no noticeable bend in the horizon, but if you walk long enough along a given direction you end up back where you started, as in a sphere. Besides, if you dig down, you'll eventually reach the center of the Earth, which is also the center of gravity (i.e. where everything falls to), and if you keep digging along the same direction (but now digging up), you'll reach the opposite point on the world. Again, like a regular sphere. The cincher is that, if you fly straight up... you eventually reach the center of the sky, which is the anti-center of gravity (i.e. everything falls away from it), and if you keep flying in the same direction (now straight down), you'll also reach the opposite point on the world's surface from where you started. In fact, if there was a perfectly clear line-of-sight (i.e. no clouds, no haze, no sun obfuscating your vision etc.), you'd also see that antipodal point by looking straight up. So it's sort of like a regular world and the "hollow world" idea both at the same time. As a D&D setting, I like to imagine the center of the sky as the central nexus of positive energy, from which all life-force flows, and which strongly repels anyone trying to approach it, while the center of the earth is the nexus of negative energy, which sucks everything down into it like a black hole, including the world's lifeforce. That would enable you to put pretty much all planes in one single continuum - the sky far above the clouds is the stereotypical Heaven where Good outsiders reside, caverns waaay far underground are the stereotypical Hell of Evil outsiders, and other "planes" (elemental, other alignments) could be simply regions in this freakishly large world. Even in more traditional settings, I like to imagine the Inner Planes organized along a similar four-dimensional structure, as they seem particularly suited for that...

[Tvtyrant]

My current setting is one where the planet has a constant series of reality maelstroms rolling across the surface. Everything, including the land, that gets caught in one gets bounced to another dimension. Life bounces back after a few days but the rocks and dirt stay changed, with the result that the surface is constantly changing and trees and animals can actually rain from the sky.

[Kislath]

I've been working on one of those "impossibly huge spaceship full of bio-decks where the inhabitants have forgotten they're on a ship" kind of things for quite awhile, ( Space Ark" http://www.giantitp.com/forums/showt...8875-Space-Ark )
but I came up with some other cool stuff, too:

1-- How about an immense blob of water, planet-sized, orbiting a sun? Inside that water are various creatures and plants, including especially these enormous, city-sized, jellyfish-like critters. The gigantic jellies have gas pockets inside them, and inside those pockets live our people.

2-- Okay, this next one is a bit stranger.
Let's suppose that someone figured out how to make little teleporters based on a small wormhole effect. The idea was very popular, and soon hundreds of them were built, and eventually thousands, all over the world.
One day, though, they went too far, installed one too many, and..
BLOOP!
The whole network of wormholes collapsed in on itself as all of the wormholes started merging together in a huge chain reaction, resulting in one huge bubble.
Inside that bubble are trapped all of the people, the thousands of them, who happened to be using the system at the time. Also with them are tens of thousands of tons of cargo also being shipped.
The teleporter network is fried, the stations themselves sucked into the bubble, and there is no way in or out of the new bubble.

Incidentally, I think I solved the problem with my Space Ark which ground things to a halt, so consider that thread resurrected.

[SirKazum]

That last one reminds me of a setting I thought about, but never developed in any meaningful way, called the "Junkyard". My idea was to use it in a game where powerful characters from all sorts of different settings (fantasy, sci-fi, superheroes etc.) meet to do battle in a huge Mortal Kombat-style deathmatch that's constantly going on. The idea is that the "Junkyard" is a place that's in a nexus of extradimensional space, a sort of "river's elbow" where stuff from teleporting and hyperspace-travel mishaps across all universes end up. Which means it's got "junk" from all sorts of settings, usually high-tech and/or high-magic stuff, as well as all sorts of people. I imagined it as a network of huge caverns, whose outer limits nobody has found so far. Food, oxygen and so on are provided by machinery like replicators (as in Star Trek) and magic items, which are salvaged by scavengers. It's a dog-eat-dog world, where competition for resouces has led to a constant struggle where only the strongest survive, and deathmatch fights (usually one-on-one) evolved to become the standard way to settle disputes and establish leadership. Anyway, Kislath's 2nd suggestion, the "wormhole collapse" setting, could provide a pretty good background explanation for that (if one is ever needed )

[jqavins]

1-- How about an immense blob of water, planet-sized, orbiting a sun? Inside that water are various creatures and plants, including especially these enormous, city-sized, jellyfish-like critters. The gigantic jellies have gas pockets inside them, and inside those pockets live our people.

2-- Okay, this next one is a bit stranger.

Oh, 'cause the first one was completely mundane!

Let's suppose that someone figured out how to make little teleporters based on a small wormhole effect. The idea was very popular, and soon hundreds of them were built, and eventually thousands, all over the world.
One day, though, they went too far, installed one too many, and..
BLOOP!
The whole network of wormholes collapsed in on itself as all of the wormholes started merging together in a huge chain reaction, resulting in one huge bubble.
Inside that bubble are trapped all of the people, the thousands of them, who happened to be using the system at the time. Also with them are tens of thousands of tons of cargo also being shipped.
The teleporter network is fried, the stations themselves sucked into the bubble, and there is no way in or out of the new bubble.

So, are they just floating in a void?

[Kislath]

Well, the floating in a void thing IS a problem, admittedly.
I suppose that the easy fix would be to say that as the system grew, the makers decided to build some huge hub station areas, and a big central HQ station.
After all, a wormhole can only connect two places at a time, right? So, in order to get where one wants to go, he can either take numerous hops until he finally connects to a teleporter that might connect to his destination eventually, or he can go to a big hub station and catch the much more convenient wormhole going right where he's going.
While they were at it, why not build some big shopping centers, restaurants, housing, etc...all in tax-free interdimensional space?
This gives us some sizeable patches of land that people can cling to, or maybe they could even get all mushed up together into a weird floating junkyard town which is itself floating in a big void.

[Valefor Rathan]

Read a sci-fi book where the "world" was a giant double helix. The different regions were able to see the curves but getting to them was such a massive undertaking that the residents didn't bother. A group of humans crash-landed their space ship and then tried to fly around/between regions.

[aspekt]

Along the lines of the previously mentioned Yggdrasil Bush there is an older European made mmo called Ryzom the setting for which is a round world, but one completely made of a tree.

[lt_murgen]

I always liked the idea of Mongo, from the 80s Flash Gordon. Kingdoms on their own space islands, floating about in a giant nebula that was itself moving.

[Eldan]

Just an idea I had... how about what looks like a normal planet, but gravity is reversed, pointing away from the planet? (The atmosphere stays on for some inexplicable reason.)

Everything, essentially, is hanging down from the ground. People would build rope bridges between cities, hanging down from the earth above. Or they'd dig caves into the ground, for safety. Plants would look totally different, hanging onto the ground with roots that extract nutrients. Drop any object and it vanishes into the sky, carabiners for everything would be essential.

I'm not sure where weather and things such as water would come from, though. Bit of a puzzle.

[Lord Raziere]

I once had an idea for a world that was an infinite waterfall, and that people lived on the various jutting out of this waterfall. they would get water from the rivers that flow from this waterfall, but due to the waterfalls constant erosion, its only a matter of time before one of the....how to say it....sideways islands? would get worn down enough at the place where water falls the most, and thus the side ways islands would at some point start falling into the unknown expanse below from the erosion, not knowing what lies at the bottom. There are people who go seeking the top and bottoms of the waterfall in airships but they are never seen or heard from again...

and thats pretty much it. I wish could've developed the idea more really.

[Eldan]

That sounds like quite a tragic world... I mean, living space would become rarer and rarer. People would war over them, knowing that it wouldn't help, in the long term.

[Lord Raziere]

hm. yes. and I'm not good at tragedy. don't like it. needs modification. perhaps say instead of rocks, the ledges are weird big branches and that the waterfall is constantly watering them so that they are slowly growing over millions of years. you can still get relatively little branches that fall off though...

[jqavins]

Just an idea I had... how about what looks like a normal planet, but gravity is reversed, pointing away from the planet? (The atmosphere stays on for some inexplicable reason.)

Everything, essentially, is hanging down from the ground. People would build rope bridges between cities, hanging down from the earth above. Or they'd dig caves into the ground, for safety. Plants would look totally different, hanging onto the ground with roots that extract nutrients. Drop any object and it vanishes into the sky, carabiners for everything would be essential.

I'm not sure where weather and things such as water would come from, though. Bit of a puzzle.

There are ways, such as described, for life to deal with this bizar situation. But how would life ever get started there?

I once had an idea for a world that was an infinite waterfall, and that people lived on the various jutting out of this waterfall. they would get water from the rivers that flow from this waterfall, but due to the waterfalls constant erosion, its only a matter of time before one of the....how to say it....sideways islands? would get worn down enough at the place where water falls the most, and thus the side ways islands would at some point start falling into the unknown expanse below from the erosion, not knowing what lies at the bottom.

FWIW, I would call them "shelves." Also, when a shelf falls, not only is it lost but it imperils all the other shelves below it as it crashes to the bottom.

That sounds like quite a tragic world... I mean, living space would become rarer and rarer. People would war over them, knowing that it wouldn't help, in the long term.

How about if the terrain around the fall is tectonicly active in a way that is constantly creating new shelves, some that grow gradually and others that break out abruptly? Naturally, they'd appear at a rate that just balances the rate of loss to errosion.

[Inevitability]

There are ways, such as described, for life to deal with this bizar situation. But how would life ever get started there?

Long ago, Myrtherius the Mad, a powerful but insane mage, sought out worlds to shape into pools of madness and terror. He created a world overgrown by thorned plants, whose residents had no protection from the sharp barbs and had to life in continuous pain. He created a world where all who died would rise as undead, feasting upon the flesh of those they loved. He created a world where, by the will of near-omnipotent creatures known as Overseers, all good was continuously being eliminated.

Myrtherius was not content, however. He decided to create a world that was the complete opposite of his own, so that humanity would be forced to live a life they had never learned to live.

A party of adventurers killed him just after he created life and reversed the planet's gravity, however, so it ended up being only moderately inhospitable. The adventurers, being your typical murderhobos, left the place be (after searching it for loot, of course) and went to the closest tavern to celebrate.



TL;DR: A wizard did it.

[Kapow]

I don't know anymore where I got the idea (could very well have been this forum). But I worked on it...

The world is essentially a (giant?) bubble in an endless mass of water. On the inside-surface of the bubble are mostly floating (sorry ) islands and some stable. In the center is something like a tiny sun surrounded by rocks.

The idea was, that once there was all water, filled with strange powerful beings (gods?, Elder Evils?,...), one of them wanted to be special, so he became fire. Others started fighting him and finally caged him into a mystically enforced "Rock". In the meantime, huge parts of the water had vaporised and in the process of the caging, big chunks of rock had fallen of the prison.

In this world, the people fear the gods, as they are either deep-sea monsters or a fiery psychotic in a cage, and the job of the priests/clerics/shamans/... is to keep their attention on them, so that the common folk won't be disturbed.

[Roxxy]

You just gave me a cool idea for my own campaign setting. The world is a shallow bowl shape. The outside is the Surface. The inside is the Underdark, and never sees daylight, but it does have stars, galaxies, and nebulai that are brighter than anything the outside gets, and they light the Underdark during their day cycle (the stars, galaxies, and nebulai disappear at night). It still looks and feels like starlight, just somewhat brighter. Somebody from the Surface would call an Underdark day dark, and would be able to see about half as far as during a normal surface day. The Underdark is dangerous, but it's native races, such as dwarves and drow, are not inherently evil. It is possible to sail from inside the bowl to outside the bowl. It is also possible to tunnel between the Surface and the Underdark (Be extremely careful, though. The crust between the Surface and the Underdark has underground rivers and magma chambers in between the areas of solid rock.).

Should I be using the term Underdark, or is that specific to the Forgotten Realms only?

I have another idea: Imagine the Surface as a curved disc. People live all around the surface this disk, except for the part in the middle. The wind always blows outwards near this area and is powerful, so sailing ships cannot get inside. But now metal hulled ships propelled by powerful fuels concocted by Alchemists are available, and they can get through the winds to the other side. The first few (known) expeditions have been sent, and more will be going soon. What have they found so far? Strange, inhuman peoples and unfamiliar creatures, and lands filled with all sorts of never before seen terrain, like flying cities that people live in or islands made of fire (that people live on) or huge underwater cities and people that are part human and part fish (!). Most confusing, however, is the fact that this place in the center of the world actually seems to be much larger in diameter than the wall of powerful winds that surrounds it. It should not be able to come anywhere close to fitting within the boundaries set by the windwall.

[jqavins]

Should I be using the term Underdark, or is that specific to the Forgotten Realms only?

Meh, so what if it is?

I have another idea: Imagine the Surface as a curved disc. People live all around the surface this disk, except for the part in the middle. The wind always blows outwards near this area and is powerful, so sailing ships cannot get inside. But now metal hulled ships propelled by powerful fuels concocted by Alchemists are available, and they can get through the winds to the other side. The first few (known) expeditions have been sent, and more will be going soon. What have they found so far? Strange, inhuman peoples and unfamiliar creatures, and lands filled with all sorts of never before seen terrain, like flying cities that people live in or islands made of fire (that people live on) or huge underwater cities and people that are part human and part fish (!). Most confusing, however, is the fact that this place in the center of the world actually seems to be much larger in diameter than the wall of powerful winds that surrounds it. It should not be able to come anywhere close to fitting within the boundaries set by the windwall.

Running with this: Obviously, the wind wall is only partly created by the tangible winds, but is also a dimensional barrier. (That's why the space beyond the wind wall is bigger on the inside.) Crossing it is dangerous as much as it is difficult; think of the ST-TOS energy barrier at the edge of the galaxy. People who aproach thinking it is just wind would tend to assume that getting back will be easy, or at least easier, because downward wind at the top of the dome would create rimward surface winds that you fight to get to the top, but you are going with the go back. Imagine their surprise on finding that this makes very little difference, as the wind is only a minority part of both the diffuculty of crossing and the danger of doing so.

[SiuiS]

Just an idea I had... how about what looks like a normal planet, but gravity is reversed, pointing away from the planet? (The atmosphere stays on for some inexplicable reason.)

Everything, essentially, is hanging down from the ground. People would build rope bridges between cities, hanging down from the earth above. Or they'd dig caves into the ground, for safety. Plants would look totally different, hanging onto the ground with roots that extract nutrients. Drop any object and it vanishes into the sky, carabiners for everything would be essential.

I'm not sure where weather and things such as water would come from, though. Bit of a puzzle.

Hmm.

The planet itself.

The planet exudes atmosphere, which rains down (outward) until it gets far enough away that it's density causes it to gravitate together. There's a thick ozone layer band at the terminus point where the planet core's weird gravity is perfectly countered by the gravitational effect if everything else in the system behaving normally.

It's also an incomplete view if the system. The plate which exudes in the material is the default, known planet, but it has contiguous form in the deep ethereal. Here, gravity obeys normal laws, such that the ethereal obeys any normal laws, and the two planets are actually one. Half of it exudes gravity, throwing thigs away, allowing life to form as it rains water and atmosphere and life. The other half draws in things that get so far lost they become spiritual; the dark half of the world sucks in dreams, ghosts, memories, and metabolizes them. The underworld/afterlife is a series of crystaline caves that convert passed on residue to energy which the light, physical half re-converts into air, water, and nutrients, passing the dead back to life.

I once had an idea for a world that was an infinite waterfall, and that people lived on the various jutting out of this waterfall. they would get water from the rivers that flow from this waterfall, but due to the waterfalls constant erosion, its only a matter of time before one of the....how to say it....sideways islands? would get worn down enough at the place where water falls the most, and thus the side ways islands would at some point start falling into the unknown expanse below from the erosion, not knowing what lies at the bottom. There are people who go seeking the top and bottoms of the waterfall in airships but they are never seen or heard from again...

and thats pretty much it. I wish could've developed the idea more really.

Ooh, neat. That's actually kinda how Ysgard works in the great wheel, isn't it? The base plane is a river of lava with rocks in it that collide and spark and erode? This is much more interesting though.

That sounds like quite a tragic world... I mean, living space would become rarer and rarer. People would war over them, knowing that it wouldn't help, in the long term.

It's an infinite water fall, though. Plus, post apocalyptic airship world! Everyone moves to air platforms and you've got the quarians, scrabbling to keep everything in good enough condition to keep everyone alive. Spelunkers develop specialized ships, launching drill systems that plow through the rushing water, burrow into the rock beneath, and start harvesting raw materials, sending them out on the anchor cable through the ungodly torrent to the harvester ships.

Eventually, two new techs emerge. The wall cracker ships, designed like miniature mining towns all on their own; they fire two or more anchors deep in to the water and rock, then play some slack. They use the downward force of the waterfall to bury them into the rock wall beneath, and then fire two more anchors, which float along the water's surface until torque and tension drive them into the rock wall. Splayed between multiple anchor sites, the city begins operation, men and women living in submarine isolation to retrieve the raw substance of survival across months before the cables snap and they need to retreat home.

The other, the struts, the race and struggle to supplement the few remaining shelves with fantastic feats of fabrication to support them, bear their loads and anchor the shelf firmly enough to effectively combat erosion. Yes. That's amazing.

I don't know anymore where I got the idea (could very well have been this forum). But I worked on it...

The world is essentially a (giant?) bubble in an endless mass of water. On the inside-surface of the bubble are mostly floating (sorry ) islands and some stable. In the center is something like a tiny sun surrounded by rocks.

The idea was, that once there was all water, filled with strange powerful beings (gods?, Elder Evils?,...), one of them wanted to be special, so he became fire. Others started fighting him and finally caged him into a mystically enforced "Rock". In the meantime, huge parts of the water had vaporised and in the process of the caging, big chunks of rock had fallen of the prison.

In this world, the people fear the gods, as they are either deep-sea monsters or a fiery psychotic in a cage, and the job of the priests/clerics/shamans/... is to keep their attention on them, so that the common folk won't be disturbed.

And at night, when the sun find and the darkness takes us, we are surrounded by billions of points of light. These aren't stars, though, no.


These are the glaring, hateful eyes and angler-fish-lures of the many legions of the aervants of the gods.

[Mr.Cobalt]

While I have not played Xenoblade myself, I recall it had a rather interesting setting: your civilization lived on the still-standing corpse of a dead god. Its limbs were even still outstretched, lending itself to some pretty unique geography.

[Eldan]

It's an infinite water fall, though. Plus, post apocalyptic airship world! Everyone moves to air platforms and you've got the quarians, scrabbling to keep everything in good enough condition to keep everyone alive. Spelunkers develop specialized ships, launching drill systems that plow through the rushing water, burrow into the rock beneath, and start harvesting raw materials, sending them out on the anchor cable through the ungodly torrent to the harvester ships.

Eventually, two new techs emerge. The wall cracker ships, designed like miniature mining towns all on their own; they fire two or more anchors deep in to the water and rock, then play some slack. They use the downward force of the waterfall to bury them into the rock wall beneath, and then fire two more anchors, which float along the water's surface until torque and tension drive them into the rock wall. Splayed between multiple anchor sites, the city begins operation, men and women living in submarine isolation to retrieve the raw substance of survival across months before the cables snap and they need to retreat home.

The other, the struts, the race and struggle to supplement the few remaining shelves with fantastic feats of fabrication to support them, bear their loads and anchor the shelf firmly enough to effectively combat erosion. Yes. That's amazing.

You know, I'm on board with that. Normally, I'm pretty instantly turned off when either "airships" or "flying islands" are mentioned, as I find both very overused and generic by this point. Step into a forum and yell "Creative Setting!" and in the first five replies, someone will say "flying islands".

But here? This is actually pretty damn cool. What would people do for food, I wonder?

[Tragak]

How about a Hollow Earth with several layers… each larger than the one on top of it?

The outermost layer is a sphere whose surface corresponds to a radius of 5 miles (area 314 sq. miles), but then digging through 1 mile of earth and falling through 1 mile of atmosphere takes you to a second surface corresponding to a radius of 25 miles (area 7850 sq. miles).

2 miles of earth + 2 miles of atmosphere beneath that: surface with radius 125 miles (area 196,000 sq. miles)

3 miles of earth + 3 miles of atmosphere beneath that: surface with radius 625 miles (4,910,000 sq. miles)

…

The "Mobius planet's" star only directly warms the outermost layer of earth, while each layer beneath is only warmed indirectly by the earth directly above. The uppermost layers are inhospitably warm, and there are a finite number of hospitable layers further down, but all layers beneath are believed to be completely frozen.

Do to the distortions in apparent distances between non-adjacent layers, the gravity of this planet cannot be calculated as reliably as can that of any other planet, so it is not even known whether the frozen layers are finite in number, let alone what that number might be if indeed it is finite.

[Lord Raziere]

You know, I'm on board with that. Normally, I'm pretty instantly turned off when either "airships" or "flying islands" are mentioned, as I find both very overused and generic by this point. Step into a forum and yell "Creative Setting!" and in the first five replies, someone will say "flying islands".

But here? This is actually pretty damn cool. What would people do for food, I wonder?

they same thing they do for any setting! some of the waterfall waters flow through rivers on the shelves that they divert into farms for irrigation. they don't know what rain is though. some probably make little mobile farms that go back and forth between the sunny zones of the shelf, and the more "rainy" zones near the waterfall itself, but not actually in the waterfall.

the sun, it eternally shines in the sky, the inhabitants don't know what a cloudy day is, they never had one, when they look down, they just see this big fluffy expanse far beneath them they call the Fog, and a big blue expanse opposite from the waterfall that they have no idea about, so they just call it The Big Blue.

as a result their directions are: Sunwards (up), Fogwards (Down), Bluewards (Away From The Water Fall), Fallwards (Towards the Waterfall) and Left and Right.

[Eldan]

I like that. Access to soil and especially fertilizer could be a problem, but they could practise hydroponics fertilized with dung, I guess.

Alternatively, periodic floods à la the nile floods. Once a year, the waterfall swells and turns a muddy brown, depositing valuable silt on the fields.

[Lord Raziere]

dude, where soil comes from is one of the last questions that need to be answered about a setting. down there with everything else pretty much irrelevant to the story, unless its real important to focus on a drought or famine for some reason, and even then, best to stick that to one shelf and leave the details open for other shelves to have different situations for more plot variance. best not to write yourself into a corner with something like this. leave details open until they don't need to be.

[Eldan]

I like details like that, and I like imagining them. I mean, do what you want in your world, but I find the idea of a vertical nile flood exciting.

[the_david]

What I came up with was a solar system (technically not a planet.) with the celestial bodies as the elemental planes.

The sun would be the plane of fire, with the planes of air (Gas giant), earth (Solid planet) and water (Liquid planet)

Easy enough right? Well, until you have to start figuring out all the orbital mechanics and the other stuff.
Things to consider:
All of the planets would be pretty inhospitable if they where made up purely of their elements. All the planes would need an atmosphere. Gravity is another one, I'd prefer to have gravity equal to Earth on all planes, but that would result in really wonky orbital mechanics. How big would each of the planes be if that was the case?
The liquid planet would benefit from polar ice caps. That means it has an axial tilt, which doesn't seem right for a ball of liquid. It could be tidally locked though, leaving one side as a massive ice cap. Big enough to have some adventures on.
The solid planet would need a body of water to sustain lifeforms on the surface. It would be more like Earth and less like Mars. It might even need a molten core if you want to do vulcanoes, and use all the other benefits the Earths molten core gives to us.
The sun would need oxygen if you'd want to put a City of Brass there, otherwise it would be just a hot ball of plasma.

Okay you got me. I don't know enough about solar systems to make this plausible.

[jqavins]

What I came up with was a solar system (technically not a planet.) with the celestial bodies as the elemental planes.

The sun would be the plane of fire, with the planes of air (Gas giant), earth (Solid planet) and water (Liquid planet)
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Okay you got me. I don't know enough about solar systems to make this plausible.

If you want it to be plausible for both physics as we know it and life anywhere close to as we know it an the sun, you're SOL (no pun intended.) It's not as bad on the water planet; life starts in the sea, so no real problem if it never moves out. Could life start in a gas planet instead of water? Pretty far fetched, but not necessarily outright impossible. A dry land planet? As you stated, pretty much not a chance.

But, you really don't need it to make sense in physics as we know it. Elemental creatures, i.e. magical creatures of each of the elements could certainly exist in environments made entirely of those elements; never mind real world physics and biology. Add a planet where the four elements coexist to be the material plane and you're good to go. Characters travelling to the elemental planets would need magical protection and other help to survive the experience.

The orbital mechanics are not really a problem either, even for real physics; space the planets out appropriately and you're fine. The Earth-like material plane planet and the water planet have to both be in the goldilocks zone, but that's not impossible, and the rocky and gas giant planets don't need to be. Getting one standard gee on the gas giant will need a little magic hand waving and once again, for the star, needs a total magic hand and full body wave.

What about moons orbiting the elemental planets for para-elemental planes?