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Is there a way to make a world without a sun even halfway believable?

I have a world that has no sun or moon and I need a way to make it halfway believable to support life. So far, I've got heat fissures in the ground that provide the necessary heat. There is an atmosphere, but the people live underground in natural caves to stay close to the heat. These caves have shafts up to the surface for air. There is no soil, just many different types of rock. The main plants that grow there are fungi and lichen, but I would like to have more, if possible. It is a fantasy setting, so the world won't have any tech or much of it at least, I don't want it to be sci-fi. It is a heavy magic world, but magic doesn't solve all the problems. There are several races there, including; humans, elves, dragonborns, vampires, shifters, dragons, and the rest are more ethereal spirit type creatures.
Quick run-down of the magic system:
Everything, sapient or not, has a soul. Magic users are called Whisperers, and they can communicate with the souls of things. They convince the souls to do what they want. They cannot change the item or make it larger or smaller than it was before. Whisperers are born with their ability, though it is possible to learn it, but it is hard enough to do that most people don't bother. (To those who have read Brandon Sanderson's Stormlight Archive, it is similar to Soulcasting. Except without the Soulcaster, you don't change the thing, and it can be done with anything as long as you are convincing enough.)

What I am looking for is ways to improve the world and how it should function so that, life in that world is not too far-fetched. I know that magic can be used to solve those problems, but I want to be a little more creative than that. I'm not looking to be super scientific about it, I just like to have a good mix of both. Hopefully, that made some amount of sense.
Any ideas or advice would be greatly appreciated.
 

Stable_Idiot

Dreamer
I think the advantage of it being a fantasy world is that you don't need too much science to back it up. You could have a setting where the only light source was feint aroura in the sky and just build in around that. You just have to show how it affects the characters. What they think about it? Was it ever different?

You've already said you don't want to have tech in the world, which would imply limited science too, so it would be believable to have your characters attribute their situation to magic or the god / gods.

As usual it's more of a show not tell situation. By explaining it too much you draw attention to it and if it's not plot central, in my opinion, you don't really want to do that.
 
As usual it's more of a show not tell situation. By explaining it too much you draw attention to it and if it's not plot central, in my opinion, you don't really want to do that.
I know, but it's the type of thing that I like to know for myself whether or not it actually comes into play in the story. Because as you already said, what I do will make a difference in how my characters think and act. But the fact that the world is completely lacking in a sun is pretty significant, so not drawing attention to it is not an option.

Go the Tolkien route. Light comes from a gargantuan glowing tree. Or maybe immense luminous gems set on mountaintops, each with it's storied history.
It's a good idea but I'm not looking to replace the sun with an alternate light source. Light isn't one of the things that I am overly worried about.

I guess I should have been more specific since light is the first thing that would come to mind. It is always dark but there is some kind of light from the stars that gives enough light for everything to be seen in as shades of grey on the surface. I want ideas on what would people do without light and how does that affect the world? There never was real light on this world so those who live there don't know what they are missing. I want to use the absence of light, not replace it.
 

ThinkerX

Myth Weaver
I know, but it's the type of thing that I like to know for myself whether or not it actually comes into play in the story. Because as you already said, what I do will make a difference in how my characters think and act. But the fact that the world is completely lacking in a sun is pretty significant, so not drawing attention to it is not an option.


It's a good idea but I'm not looking to replace the sun with an alternate light source. Light isn't one of the things that I am overly worried about.

I guess I should have been more specific since light is the first thing that would come to mind. It is always dark but there is some kind of light from the stars that gives enough light for everything to be seen in as shades of grey on the surface. I want ideas on what would people do without light and how does that affect the world? There never was real light on this world so those who live there don't know what they are missing. I want to use the absence of light, not replace it.


Ah...you'd still need heat though, or the planet would be an icebox, unless your inhabitants dwell several dozen miles below ground.

A bit of real world science. New 'earth-like' planets are discovered fairly often these days. Owing to the detection methods used, the vast majority of these worlds orbit very faint 'Red Dwarf' stars. How faint? If our sun was a 100 watt light bulb, these stars would be teeny-tiny LED lights...at best. Make matters even worse, many of these faint sparks are 'flare stars' - meaning that at erratic intervals they put out monster solar flares that can double their apparent brightness.

'High noon' on such a planet would be more like 'faint twilight' here on earth. It'd also be on the cold side. And the flares would be downright deadly.
 

elemtilas

Inkling
Write me a good story, with good characters, an engaging plot, and a delightful world, and I'll believe anything you tell me about it!


Magic is a thing, which is great, and you've already got some ideas cooking.

You might want to take a look into rogue planets. These are actual planets that have been given the boot from their parent star systems and literally wander through the heavens.
 
I get the power from the geothermal or hyrogenerator if you would like the science fiction round. The snow piecer dystopia here we go. If you want to go the fantasy novel, the crystals in rpg game explains everything for some reasons.:cat:
 

Saigonnus

Auror
I think the idea has genuine value, and should be fleshed out a bit more. Though I am certainly not an expert, I believe that scientifically, the planet wouldn't need a sun or moons to still be viable for life. As long as you can figure out exactly how the various processes interact with each other to provide for the life they give. If the planet is like earth; with a molten iron core, then you'd have a natural magnetic field, the start of an atmosphere. Another option would be a "magic field" surrounding the planet serves as the same thing, but given how you described your magic, that probably wouldn't be right.

If there is an atmosphere, then there is no reason the sapient creature couldn't live on the surface. Either they would cluster near the hot water geysers or hot springs, or since there is an atmosphere, perhaps the surface temperature is something that can be tolerated with special clothing or genetic adaptation. You wouldn't actually "need" a sun to provide enough heat. An idea would be the magnetic pull of the planet attracts a few "energetic" meteors or asteroids that wick off something that interacts with the atmosphere, creating a thermoreactive process. A simpler process might involve particles in the air thrown up by the plumes that serve as a blanket, keeping the surface temperature at a habitable level given the heat from the core can't escape into outer space.

Any plantlife on the surface wouldn't follow the photosynthetic model, but would likely absorb sulfur or ammonia (from the vents) and could excrete oxygen. The vents/geysers/plumes might also expel hydrogen and nitrogen, or maybe the fungi reacts with the ammonia and excretes one or the other, there are many possibilities scientifically. As for the watershed, it wouldn't be far-fetched to think there is a series of fresh water aquifers kept warm by the same geothermal heat, and are expelled onto the surface via springs or geysers. Having something like that could add moisture to the atmosphere as well (perhaps the geysers are more like plumes that shoot the water to the stratosphere, adding hydrogen and oxygen). For light, the denizens would probably have adapted to low-light conditions; and iridescent plants might provide a bit of natural illumination; similar to those plants on the movie Avatar.
 

Ruru

Troubadour
Sounds like an interesting concept. One of my first thoughts was what impact having next to no light would have on your characters. Do they not really use facial expressions? Expressions became critical to humans in a group context, but that's visual, so if you have little to no light, would your characters give their social ques through another means? E.g is everyone super tactile, as in you touch when you talk, maybe touching faces is a form of greeting. What about pheromone based communication? Art might be touch or scent based. Maybe music is a really big deal to people? Would the languages be much more tonal, since sight has a back seat in your world? Audio would become a big deal, perhaps that would mean developments were made early in long distance speaking, well ahead of any other tech? Or maybe your races are telepathic to some degree? Writing would likely be tactile in some form or another, like braille I suppose.

I love world building, but I'm definitely more on the sci-fi side of things when it comes to the way a world might work, so apologies if I've gone too far that way. Heat would be a huge issue on a plant with no sun, but if your planet had a hotter core than Earth does, that might be enough to give you live-sustaining warmth. Or perhaps your cities have a form of magical heating. That would create a job system too; civil servants that keep the spells fresh. You could delve into that as a socio-economic thing too: 'country' folk might not have the means to run heating spells, but the cities do.

Your food sources could be a lot of fun. With no sun, your ecosystems would have a chemical energy source, rather than light energy trapped by plants. On earth, most of those systems are deep underwater in thermal vents. I once dreamed up dragons that ate rock and were essentially organic nuclear reactors, using the breakdown of elements to generate energy and fire. You could do things like that without needing to delve into the details much.

Religion is another place there would be a big impact. Many of earths earliest religions revolved around the sun. What would your races worship?

Sorry for the brain dump, but there are some thoughts!
 

Stable_Idiot

Dreamer
I know, but it's the type of thing that I like to know for myself whether or not it actually comes into play in the story. Because as you already said, what I do will make a difference in how my characters think and act. But the fact that the world is completely lacking in a sun is pretty significant, so not drawing attention to it is not an option.

If you have to know that I'd make the explanation rooted in fantasy rather than science, that way you avoid the temptation of introducing ideas that don't fit your world.

As mention above Tolkien had the Two Trees of Valinor or in my previous example the Aurora could be the breath of a dying God -- rather than radiation from a dying star hitting the magneto sphere of the planet.
 

A. E. Lowan

Forum Mom
Leadership
According to astrophysics... maybe. The problem with having no sun is that there is no larger body for the planet with a bigger gravity well to orbit, thereby leaving it to wander aimlessly through space, usually dead and lifeless. A possible alternative to this might be found in the moon Europa, which is completely covered in frozen oceans with a thin layer of liquid water near the bottom. But, with Europa, you have a distant sun and a closer planet contributing to heat generating tectonic activity.

You see, with no sun, you have no heat. You basically have a rock wandering loose in space with no sun to fuel atmospheric processes or a rudimentary water cycle. So you're going to have to think carefully about generating heat, about comets, asteroids, and other bodies that will be attracted to your planet's small gravity well.
 

Stable_Idiot

Dreamer
According to astrophysics... maybe. The problem with having no sun is that there is no larger body for the planet with a bigger gravity well to orbit, thereby leaving it to wander aimlessly through space, usually dead and lifeless. A possible alternative to this might be found in the moon Europa, which is completely covered in frozen oceans with a thin layer of liquid water near the bottom. But, with Europa, you have a distant sun and a closer planet contributing to heat generating tectonic activity.

You see, with no sun, you have no heat. You basically have a rock wandering loose in space with no sun to fuel atmospheric processes or a rudimentary water cycle. So you're going to have to think carefully about generating heat, about comets, asteroids, and other bodies that will be attracted to your planet's small gravity well.

If you were writing a sci-fi fiction I'd say you might need that level of detail, but in a fantasy world I'm not sure your characters would ever look at it that way. The point I was trying to make is that a fantasy world doesn't have to follow the rules that exist in our universe. Pratchett's books don't lose out because his world is a disc carried by four elephants on the back of a giant turtle drifting through space; it's the plot that carries a reader through your story. I think Hir i-Chorvath's world makes sense as it is. If the fact that the world is dark has particular significance to the plot then by all means explore it, otherwise the fun is in simple writing how it effects the characters lives.
 

Stable_Idiot

Dreamer
But the fact that the world is completely lacking in a sun is pretty significant, so not drawing attention to it is not an option.

Also just want to point out that the lack of a sun is only significant to your characters if at some point they've experienced the world when it had a sun. Otherwise they have nothing to compare it to, it would just be the way the world is. There's a well know philosophical concept called Plato's Cave that explores the idea, in essence we can only know the things that we know unless something enters the system from the outside and introduces new knowledge.

Having said all that, it could make for a fun plot in of itself. If the world was light in recent memory or one of the characters discover a source of information that there had been more light at some point, could add some mystery to the world. :)
 
Ok, thanks for the input so far.

If you were writing a sci-fi fiction I'd say you might need that level of detail, but in a fantasy world I'm not sure your characters would ever look at it that way. The point I was trying to make is that a fantasy world doesn't have to follow the rules that exist in our universe. Pratchett's books don't lose out because his world is a disc carried by four elephants on the back of a giant turtle drifting through space; it's the plot that carries a reader through your story. I think Hir i-Chorvath's world makes sense as it is. If the fact that the world is dark has particular significance to the plot then by all means explore it, otherwise the fun is in simple writing how it effects the characters lives.
You have a good point there, but I like to use science to come up with ideas for my worldbuilding. I won't keep it as science, I plan to twist it and make it magic that is grounded in science. I think that it makes the world more realistic. I know that isn't the point of fantasy, but that's just the way I like to do things. I blame it on my dad since he's a physicist/engineer.

Sounds like an interesting concept. One of my first thoughts was what impact having next to no light would have on your characters. Do they not really use facial expressions? Expressions became critical to humans in a group context, but that's visual, so if you have little to no light, would your characters give their social ques through another means? E.g is everyone super tactile, as in you touch when you talk, maybe touching faces is a form of greeting. What about pheromone based communication? Art might be touch or scent based. Maybe music is a really big deal to people? Would the languages be much more tonal, since sight has a back seat in your world? Audio would become a big deal, perhaps that would mean developments were made early in long distance speaking, well ahead of any other tech? Or maybe your races are telepathic to some degree? Writing would likely be tactile in some form or another, like braille I suppose.
You bring up a lot of good points here. Unfortunately, I did not have the foresight to think about any of this and I don't have any answers. So thank you for those questions, I will figure out the answers to those.

From the ideas that have been given to me so far, this is what I have:
The world has several naturally formed chasms, caverns, tunnels, and rifts. Most people live underground but others still live on the surface. The surface is similar to a desert.
There are no seasons for obvious reasons, same as there is no night or day. This means that the plants all grow like weeds and keep growing, otherwise everyone would probably starve.
There are rivers of lava that come from the core or just exist and for unknown reasons stick around. I'm not going to get scientific with that one. Something to do with dragons.
There are several underground lakes and seas, water gets to the surface through geysers, but the water just stays there in stagnant pools. That is as scientific as it gets right there.
There is raw magic called Siar which is liquid and only appears on the surface of the world, forming in said pools. Certain types of stone have their own special abilities though the locals wouldn't call them magic because to them, it's normal. Same as some plants, which I have yet to come up with in any significant amount of detail.
The magic system just relates to the magic that humanoids and other sapients can use and not to the things that happen naturally.
humanoids have two types of vision, heat and normal. (similar to darkvision as described in the Drizzt Do'Urden series by R. A. Salvatore) I have been toying with an idea given to me by a friend that their eyes or some other part of themselves glow or they can make that part of themselves glow at will.
I am going to look over the whole asteroid/gravity mess, I'm okay with saying that magic solves that problem or maybe the god.
Types of stones so far:
- Emit light, more of a soft glow than anything else.
- Emit heat, only found around the rivers of lava.
- Still working on the kinks in this one but when a certain process happens to it then it bursts into water.

And I guess that I should have mentioned this way before now, but there is some overlying plot to the origin of this world:
I have four worlds that I have been building and a couple of stories that take place on each. There are two gods and two goddesses and each created one of those four worlds. They are all siblings and are relatively new to the whole being a diety thing. They were supposed to work together and create one world, but as siblings often do, they disagreed with each other and didn't get along. So instead each of them made their own world. Since they didn't work together as they were supposed to, each world is flawed and will eventually die. This world was made by one of the gods who decided that his world didn't need a sun for no other reason than everyone else had one. He thought that he could make a world that was just fine without one and that is what he did. The overlying plot continues but that's all that's is relevant to building the world.

So now that I've got this kind of figured out, I'm going to narrow down the focus of my questions to things that would have been impacted by the world but not necessarily about the actual world itself, though feel free to keep up with the previous.
What would be some interesting types of plants that might grow there that aren't fungi or lichen? (magic-based, just wondering what comes to mind)
What are the opinions on my friend's suggestion that eyes or some other body part should glow?
Other types of stones?
What would people use instead of wood?
What would clothes be made out of?
If anyone has ideas on how to connect rivers of lava and dragons that would be appreciated. The dragons that I use are western/D&D type.

Thanks for taking the time to read this and putting up with my scatterbrained ideas. :)
 

Saigonnus

Auror
What would be some interesting types of plants that might grow there that aren't fungi or lichen? (magic-based, just wondering what comes to mind)
What are the opinions on my friend's suggestion that eyes or some other body part should glow?
Other types of stones?
What would people use instead of wood?
What would clothes be made out of?

Well, hypothetically, dwelling underground for long periods of time without light could make a race completely blind. They might use infravision (sees gradiations of heat rather than light) or if there is a bit of light (from crystals, mosses, lichen etc...) then low-light vision. It might even cause the irises or eye themselves to become larger to take in more light when very little exists.

Given that magic is common, perhaps like the Drow in D&D, your races might employ magic to create light, and keep a light/dark cycle; which would likely be based more on their natural sleep/circadian rhythm. If they are elves and only need to sleep 4 hours, then it would be darker for those hours and the rest of the time would be more brightly lit. Since they are a "created" race, the god would dictate their particular needs for sleep, you could use any sort of light cycle you want. You could use a natural 12 hour on/off cycle or a 4 hour on/off cycle; whatever would make the world interesting. You might even have crystalline stalactite and stagmites that glow constantly.

For wood, you might have roots that grow constantly and quickly, or dried mushrooms, or even the manure of livestock. With magic, you may not even need it. Think about how your race would actually use it. For cooking, you could have enchanted flat rocks that you can grill stuff on, and the same could be true for heat.

Clothing can be made from the silk of spiders, worms, grasses, natural fibers from the aforementioned roots or if you have livestock, leather.
 

scink

Acolyte
I have a world that has no sun or moon and I need a way to make it halfway believable to support life. So far, I've got heat fissures in the ground that provide the necessary heat. There is an atmosphere, but the people live underground in natural caves to stay close to the heat. These caves have shafts up to the surface for air. There is no soil, just many different types of rock. The main plants that grow there are fungi and lichen, but I would like to have more, if possible. It is a fantasy setting, so the world won't have any tech or much of it at least, I don't want it to be sci-fi. It is a heavy magic world, but magic doesn't solve all the problems. There are several races there, including; humans, elves, dragonborns, vampires, shifters, dragons, and the rest are more ethereal spirit type creatures.
Quick run-down of the magic system:
Everything, sapient or not, has a soul. Magic users are called Whisperers, and they can communicate with the souls of things. They convince the souls to do what they want. They cannot change the item or make it larger or smaller than it was before. Whisperers are born with their ability, though it is possible to learn it, but it is hard enough to do that most people don't bother. (To those who have read Brandon Sanderson's Stormlight Archive, it is similar to Soulcasting. Except without the Soulcaster, you don't change the thing, and it can be done with anything as long as you are convincing enough.)

What I am looking for is ways to improve the world and how it should function so that, life in that world is not too far-fetched. I know that magic can be used to solve those problems, but I want to be a little more creative than that. I'm not looking to be super scientific about it, I just like to have a good mix of both. Hopefully, that made some amount of sense.
Any ideas or advice would be greatly appreciated.

Your story appears to use base human characteristics and limitations. Maybe transcend the restrictive essence of human ways and evolve species that have senses beyond those that we understand. Magic is a human fantasy creation which basically allows the laws of science to be broken. It is way too simple a mechanism. The creatures existing within your world would have evolved in a way to suit their surroundings. Less human more shape shifting , melding, telepathic beings that traverse as mist and reform to suit changing conditions. Races and cultures that control the mechanisms for survival and group in like environments. Focus on the nutrients and the sustenance given from rocks, fungi and gases and consider the controlling ways species would have evolved to persist in this environment.

If you bring into the story the lack of moon and sun in a human type environment then you also remove gravity and any form of heat. The science of that world needs to be beyond anything that you can imagine and will only exist if its base science has a different vocabulary completely. The sun and moon and planetary bodies are in a state of equilibrium based on time and our understanding of it. Loop outside of that constraint and form a whole new evolutionary strain of creatures that have never perceived light or dark or heat or gravity. The senses we have are a product of our environment. In your world without the balance of light, dark, gravity and warmth from a controlling body you would need to replace with other defining factors.

You do not need to explain and make sense of anything in your world. Your rules and your definitions. Also look for one element or significant factor that holds the world together. You need something to replace the light.
 
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skip.knox

toujours gai, archie
Moderator
If there's no sun there's no energy. Everything is dead. There are no tunnels or crevasses, no heated core. There's nothing at all. Sorry, but thermodynamics is unforgiving.

I suppose you could posit a planet orbiting another, larger planet--might require a system of planets--and tidal pull could work up a smidgen of heat, but that would dissipate and in any case could never work up enough energy for life to evolve.

Now, if you took a living, working planet, then threw it out of a solar system somehow, there might be a century or two in which to write a story, but not long enough for there to be any real biologic adaptation.

Full disclosure, I'm a historian not a physicist, so I am happily corrected on any of the above points. But I don't see how one has such a world without a healthy dose of handwavium.
 
There are two main possible sources of energy. There's either magic, which allows some handwavium to explain the world.
And there is nuclear fission. This produces heat, keeps the core molten, which in turn gives you thermal energy as well. You probably need more radioactive material then what you find in our world, but it could work I guess. Not sure if you get intelligent life on such a planet, but then, why not... I think there are earth bacteria which survive and even thrive in high radioactive environments.
It could give an interesting feature to creatures living there. The biggest issue with radioactive material is that is destroys DNA. What if the creatures would have "fluid" DNA, which changes as desired. It would counteract the radiation's effects and you could potentially have a race of shape-shifters.

As for the question is there kinds of planets exist. It is believed they do. Mainly as planets that escaped from their star's gravitation. But since they are dark, they are close to impossible for us to find. So we can't prove it
 

Miles Lacey

Archmage
I had the idea of a giant lightbulb instead of a sun. It doesn't have to be logical or scientific. It just has to be an alternative to a sun. And the idea of a Great Divine who turned on a light that, in His lifetime, is a few hours, but for the people on the planet is a billion years.
 

Insolent Lad

Maester
There was an Asimov novel (or series?) in which a portal of sorts is discovered that allows the transfer of energy from one world/universe to another. Endless free energy (but there proves to be a catch, as I remember it, like the universe overloading and exploding or something like that). I've used a variant of that for the demon character in my WIP—it has to open a portal to its home world now and then to 'feed' from the light of the red sun there. Anyway, that's one pseudo-scientific and/or magical way to provide energy to an energy-less world.
 
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