I got an idea last night for my Sci-Fi x High Fantasy(?) world, where a continent South of the equator on a world not too much unlike Earth is permanently dark (edgy I know, but I could do with more edge in my story ). The concept is essentially a volcano that is constantly* emitting ashy fumes over the continent. An ancient civilization called the Gigas built a floating wall in the stratosphere** that prevents the fumes from spreading past the continent. What would this entail in terms of effects on the continent itself? *Unsure of whether a volcano constantly, and I mean indefinitely, emitting fumes is believable. **If they built a floating wall there (ignore the questions that come with a floating wall, my science magic covers that part), what would the fumes do? Would the leak over the wall and continue through to the rest of the world anyways? Would it have to be a dome? As you can see, I'm not that knowledgeable when it comes to anything past Wikipedia, so I figured I'd come here for some possible insight.
Yes, they would leak through the wall unless it was air tight. A lot of what makes massive volcanic eruptions are such catastrophic to biospheres is not so much the ash, but the gasses it spews. The smoke is particulate matter, which if enclosed would simply sink in the air once it cooled. (While hot though, it would easily reach past the stratosphere so it'd still leak out the top.) Most ash during a volcanic eruption though is from burning coal and trees, which would soon become exhausted. If you look at real volcanoes that spew endlessly like in Hawaii, they produce very little ash. CO2 is the biggest issue with volcanism. It drastically increases the temperature of the planet and turns water into acid.
A permanant dust cloud over your continent would mean no sunlight, which means no plants, which means your civilization would have to work off of a food chain similar to the ones in caves or near deep sea thermal vents. No sun also means it'd be cold. Like damn cold anywhere it isn't near a volcano, and then it'd be pretty darn hot and difficult for humans to live in because of the aforementioned fumes and gasses.
This sounds like an interesting idea to me. Instead of a wall maybe they have some way to extract the gases/ash and sequester them? Or use them as material/fuel/whatever. You could still refer to it metaphorically as a "wall" if they were efficient enough at it that they could extract and sequester all of the gases/ash and kept any from reaching other continents.
That's true, it'd be similar to a nuclear winter. However, it would depend on how long the volcano was spewing CO2 into the air. When that happened on Earth at the end of the Permian, the extra greenhouse gas made the temperature skyrocket.
It would also depend on the carbon cycle of the continent and how the floating wall works, whether it completely contains all gasses and if it keeps out any thermal air or ocean currents.
Thanks for the reply, but this does bring up a few things as well. On the topic of ash and gas production, I don't know if this is possible or what this would entail, but the idea is that there is a crystal in the magma chamber that is constantly using heat from the surrounding magma, and occasionally consumes heat in large bursts (though in moderation). Don't worry too much about the science of it, but the reason it's not crushed from pressure is because magic force-field. Would this consumption of heat make the volcano produce more ash? Or even be possible without solidifying the magma or whatever? This also gave me an idea. I want to keep the wall concept, but I also see that it wouldn't really do much. Maybe vents in the wall would gradually absorb the gases from the cloud, and transfer them to pods in the wall's many columns. The pods would, when filled, shoot down to the coast/sea to be gathered and treated for clean air. Not sure how the treatment process would go though, maybe some magic/alchemy involved. Also if this sounds like doing way too much, it's fine. That's like the theme of my story . I want to make sure it's as dark as possible. The continent is basically going to be the home base for the undead army, and these ones burn in the sunlight (or rather, their souls do).
It's possible without solidifying it, but it'd have to be done slowly as heat travels through the mantle is an insulator. When lava hits water, you'll have a similar sudden cooling process. Most likely, your crystal would end up with a solid layer around it, which it would then have to let melt again before it can draw in more heat. Removing some heat would not produce more ash. It'd be difficult to remove enough heat to really effect it since the amounts of energy contained in the mantle is enormous.
I think you might need to step out of the idea of a volcano as it would have detrimental effects on the planet. Here's a few of my ideas ^^ Depending how large the continent is, you could maybe put it in a dark spot similar how we never see a different side of the moon from earth; If the rotation of the planet around its axis is as fast as it rotates around the star one side would always remain in the dark. Can't remember the name of the movie, but there was a planet that had 22 years of light and 22 years of darkness, because a different planet would orbit infront of it. Same with how the moon can create a solar eclipse, creating a shadow on earth. The above can also be done with a structure; a space elevator falls as fast to the ground as it falls around the planet, meaning it remains stationary in the sky. If you have a huuuuuuge structure, this could darken maybe an entire continent if the creator didn't care about the conscequences to the ones below. Hope this has been of help.
This would require an extremely lucky impacter not far after it formed to get the rotation right (like Venus.) The moon always faces us because of a process called tidal locking, and that only works if the two objects are very close together (the moon used to be much closer.) Planets can not be that close together, they would throw each other out of orbit. However, a planet that is far from the sun and tipped on it's side will have a day that's equal to half of it's year. Uranus is in this configuration. It has about 100 years of darkness followed by 100 years of sunlight. It'd have to be at least as large as the continent and probably quite a bit larger, but doable. There is an object called a Dyson sphere or Dyson swarm that could black out large parts of a planet. (Usually we think of dyson spheres around stars though.)
Luck doesn't matter, isn't that what is basically the creation of anything we know? Technically they could be, similar with how space elevator, but the planets need to go quite a signifact speed around the star for that. If two planets are close to each other, the gravitation force towards each other would either cause them to crash into each other or most likely slingshot one or both out of the (solar?) system. But if the gravational force is as strong as the centrifugation force wouldn't that make it plausible that those planets can remain near each other and the planet closer to the star creating a permanent shadow? It needs to be indeed super large. I don't think a dyson sphere would work as you either have an incomplete one, meaning you'd have inconsistencies within the dark patches, or the entire planet is darkened.
You could have an incomplete Dyson sphere that only covers part of the continent. You’d have to have it in geosynchronous orbit to stay out and be larger than the continent in order to keep t covered as the planet rotates. No, sorry, if two planets get too close to each other, they will pull easy other. There is no stable three body system that would keep two planets close to each other. Not to mention that planets are so far apart that you usually can’t even tell it’s a disc (nobody knew that u til the 1600s.). Venus and Earth are quite close to each other, but we’re still only a dot in each other’s sky.
Well, mathematically you could have a binary planet that orbit each other around their barycentre like Pluto and Charon do, and they could in turn orbit a star, but I wouldn't put bets on that system staying stable for too, too long.
Like I said, centrifugal force needs to overcome the gravitational one. Like @The Dapper Hooligan said, mathematically it could work, most likely not stable though. But in my opinion, with the countless of planets, and anything within the realm of possibilities is usually enough for a story.
In my story, the planet was struck by an external force early on in its lifetime, but I haven't decided on the details yet. I could, to go with the idea of one permanently in the planet's shadow, have the comet that strikes the planet be one large enough that it tips the planet off balance. I don't know exactly what else that would entail though. Where would it have to strike to cause a (let's say Australia sized) continent to be put into total darkness? I guess this would also depend on the moon's position, which I haven't even decided what I should do with yet.
Yeah, but then you'd have an eclipse every lunar month, not permanent. Only if the orbit of the planets exactly coincided with the orbit around the star could you permanently bath part of the planet dark. It may or may not be mathematically possible, but it should be calculable, so if the OP wants to go in that direction, I could do the maths to figure it out. Unfortunately, a comet is not large enough to tip a planet over, not even close, the magnitudes of momentum involved are insane. Only complete, planet destroying cataclysm can do that. Fortunately, these are quite common when solar systems form. It happened at least 3 times in our own: Venus was hit by something nearly as large as itself, which is why it rotates backwards today. Earth was hit by a planet the size of Mars called Thea, which is what gave us our moon, and Uranus may have actually been hit by two different objects far larger than Earth to knock it completely on it's side. Young solar systems are chaotic and have dozens of proto-planets in them, which occasionally collide. Each collision completely liquefies the planets. Still, tipping over a planet doesn't solve your problem. It'd simply give you a half-year long day. You can't extend that time by moving the planet further away because then you freeze it. If you increase the output of the star to compensate, you speed up the orbit again by adding more gravity. Were there previous inhabitants of your planet or some forerunner technology left there? An array of huge objects in space could darken a particular region of the planet below by changing the orientation of large peddles. This is not even that far of a stretch because humans have already done something similar, but in the opposite direction (we added light, but the same technology could be used for shade.) The Soviet Union used a giant space mirror to light up night in an experiment called Znamya.
If your planet had rings, your dark continent was on the equator, and your planet had very little axial tilt to it, you could theoretically have a dark, or at least relatively shaded, continent. This dark section would extent from horizon to horizon, though, and not just be localized to the landmass itself.
There is an ancient civilization in the story that still exists to the present day, and they have crazy high tech stuff. It's all by magic though, so like their floating city is powered by magic, and they have entire lakes covered in camouflage through magic. The reason I try to limit these big magic structures or devices is because they need dedicated souls and a constantly renewing power source. This kind of magic can only be performed with a soul and a catalyst (ex: a human and its soul), and it needs a power source to draw from (ex: a constant flow of water), so a giant sunblock in the sky would need something to keep it afloat.
