Could Coruscant (or something like it) be possible?

[hawkinator]

Basically, could you actually create a world spanning city (Coruscant from Star Wars being the example here)? Could it be self sustaining? (I.e. not completely dependent on external shipments of stuff) Where would the rich / poor segments end up? Other questions you would like to answer/ have the answer to... And, most importantly, what would it be like to live there?

Edited August 28, 2014 by hawkinator

[Brethern]

Just so we're clear coruscant isn't self sustaining. Food is grown off world and shipped there.

For this I'm assuming you would need three things.

Since there's not going to be any plants to recycle CO2 it's going to have to be done through artificial means. probably giant processing plants that are located everywhere.

The buildings would affect the temp so you'd need some way of regulating the temp getting it warm enough (which is done in the EU via orbital mirrors) and not letting it get too hot. Giant heat sinks? Gravity generators to lower the gravity to allow the gasses to escape the atmosphere?

Finally if you want it self sustaining you'd need a food source that grows fast. No ideas about this one.

As for the rich poor areas the lower levels would be poor and the high up be rich.

[Nuke]

the only real requirement is you need to provide a biosphere through artificial means. this is going to utilize a lot of power. i figure the atmospheric reprocessors will be attached directly to the power stations, which would likely be fusion based (like the thing they had in aliens for terraforming). you also need to feed everyone. given enough power you can do hydroponic farming. this can be done in tall buildings and so would take up a lot less space than a traditional farming infrastructure. your main issue is you cant get any natural resources from the city planet, since every square kilometer if covered with buildings. so this kind of configuration probibly isn't viable unless there is an interplanetary economy to feed it. you are probibly better off doing a massive space colony and leave the planet there for mining.

[Godot]

I agree with both answers provided.

As for food:

If energy is no problem you could have giant hydroponic farms ... maybe in underground caves with huge artificial lightsources that imitate the stars spectrum.

A bigger problem IMHO is waste processing and water.

A city the size of a planet will need huge amounts of water .... its inhabitants will also create huge amounts of excrements.

If we want to have a Coruscant that is self sustainable to a large degree, we would definiely need methods of waste recycling that are close to 100% efficient.

Escpecially with regards to the water recovered. Else Coruscant would always be dependant on a huge fleet of waste collector ships (to ship waste off world) as well as ice ships (to bring in new water)

[OgreMagi]

well

given the tech of Starwars is rather extensive and they built a small moon for a battle station ( death star) coruscant is rather small potatoes... it is the capital of a galactic empire..

[Seret]

Single-environment worlds are just an aesthetic thing Star Wars does. Coruscant isn't any more realistic than Tatooine or Endor. They couldn't exist in reality.

[WestAir]

If it's possible to make a single self-sustaining hydroponic skyscraper, then doing that a hundred thousand times, inches from the last, probably isn't much of an issue. As for water, if we took Earth and turned it into a giant city we'd have about 70% of the surface being water to build over - that's a lot of water to desalinate, but if tech isn't an issue it's certainly a start. If you design this in building blocks, one piece self sustaining at a time, I'm sure there's ways you can make it work. Organic life is nothing but a constant transfer of energy anyways. Turn oxygen into CO2 and back, turn water into waste then back into water, etc etc. With the proper planning I imagine it could be done.

[Scotius]

Question is, if such metal-covered world would be able to sustain ecosystem human(oids) would be able to survive in. Water cycle alone would be severely impacted. Weather patterns, temperature - heck, planet-sized city would churn so much heat and light into atmosphere there would be almost no recognizable day-night cycle. I certainly would not want to live there

[Seret]

The question has to be asked: if a civilisation was able to climb up and down gravity wells so easily that it could economically grow food on other planets and ship it to feed this vast city, why bother squeezing that whole city onto one planet at all? Maintaining a viable biosphere without the planet's normal feedback loops would be so hard that it'd be easier to just ship people out to the other planets that were supporting it and build accommodation for them there.

Star Wars isn't hard sci-fi, there's no point trying to scrabble around for a plausible explanation for most of what's in it. I love Star Wars, but it's basically a nonsense kids story about space knights with magic swords. It's complete cobblers, but great fun. Can't wait to see what the new ones are like.

[Umlüx]

i think its the same thing with us, coming together in big cities. we too need farmland to sustain us.

coruscant is the same, only scaled up.

[Seret]

i think its the same thing with us, coming together in big cities. we too need farmland to sustain us.

coruscant is the same, only scaled up.

Yes, but why bother with the complication of having the city's hinterland on another planet? Just shift the excess population to one of the planets that's got the arable land and you're done. If it's cheap enough to fly bananas from that planet every day then it'd be cheap enough for people to emigrate to it.

It's not something that is supposed to actually make sense though. Single-environment worlds is just a Star Wars gimmick. It's like the way light sabres can parry each other, but nobody has ever thought to apply the same technology to other stuff to make it light sabre proof. You're not supposed to think about it too much.

[Umlüx]

right. star wars is a scifi opera, a fable. carrying bananas from one system to another is as casual as driving to work

[Sky_walker]

Yes, but why bother with the complication of having the city's hinterland on another planet? Just shift the excess population to one of the planets that's got the arable land and you're done. If it's cheap enough to fly bananas from that planet every day then it'd be cheap enough for people to emigrate to it.

The same could be said about the Earth. Why people live in London which requires food and water to be brought not only from entire Great Britain but also Europe and parts of Africa while you could just as well move people to the Ukraine / Kazakhstan / central asia where rich Chernozem provides more than enough food to sustain population?

Star Wars Coruscant is just up-scaled capital city. Only that one serves thousands of planets instead of a single country. Hence the size.

Single-environment worlds are just an aesthetic thing Star Wars does. Coruscant isn't any more realistic than Tatooine or Endor. They couldn't exist in reality.

You mean just like Mars and Europa? Surely desert and ice planets/moons cannot exist... no way...

BTW: No planet in Star Wars is purely a single-environment. Coruscant is no exception to that - in fiction it got an ice caps on poles, and different temperatures on different latitudes.

Edited August 28, 2014 by Sky_walker

[magnemoe]

The same could be said about the Earth. Why people live in London which requires food and water to be brought not only from entire Great Britain but also Europe and parts of Africa while you could just as well move people to the Ukraine / Kazakhstan / central asia where rich Chernozem provides more than enough food to sustain population?

Star Wars Coruscant is just up-scaled capital city. Only that one serves thousands of planets instead of a single country. Hence the size.

You mean just like Mars and Europa? Surely desert and ice planets/moons cannot exist... no way...

BTW: No planet in Star Wars is purely a single-environment. Coruscant is no exception to that - in fiction it got an ice caps on poles, and different temperatures on different latitudes.

Main problem would be power use and overheating, an planet wide city would use an lot of power, and yes an planetary city would only work if power is dirt cheap.

Niven's puppeteers home planet is a bit more realistic in that it has oceans who produce most of the oxygen on a planet.

You might need to shield the planet from sunlight or move it away from the sun like the puppeteers did, however he did not explained how the plankton survived without light.

Another problem with a planetary city is if the people want it, at least the upper classes, no reason to not outsource manufacturing to the farming worlds to get more room.

Mars has polar regions with ice and frozen co2. Airless bodies has one environment, vacuum and rocks. Planets with an dense atmosphere like Venus and gas giants also has small variations.

An earth like planet will have multiple environments.

[Seret]

The same could be said about the Earth. Why people live in London which requires food and water to be brought not only from entire Great Britain but also Europe and parts of Africa while you could just as well move people to the Ukraine / Kazakhstan / central asia where rich Chernozem provides more than enough food to sustain population?

The difference being the the presence of London, or even all the world's cities put together, doesn't pave over all arable land and inhibit the biosphere's natural cycles that keep Earth habitable. Large cities are feasible, planet sized ones aren't. Cities do require hinterland, once a city has increased so that its hinterland takes up the whole remainder of the planet it's reached its maximum size. Suggesting that the hinterland is located on other planets is just bonkers economically.

Look, Star Wars is cool, but most of what's in it makes no sense and is just done for spectacle or as an homage to the movies George Lucas watched growing up. You just have to take it all at face value.

[Jovus]

Look here, here, here, and here for a fairly extensive take on the possibility of Coruscant (and comics! with legos!).

[Sky_walker]

The difference being the the presence of London, or even all the world's cities put together, doesn't pave over all arable land and inhibit the biosphere's natural cycles that keep Earth habitable.

That's because our large cities still have space to grow wide instead of tall.

Look at the Honk Kong instead - it pretty much paved all of the arable land and inhibited natural biosfere on it's own island.

Now just up-scale it to the size of empire spanning thousands of planets and you end up with Coruscant.

Large cities are feasible, planet sized ones aren't.

That feasibility is directly proportional to the technology.

Honk-Kong would not be feasible in first century B.C. even if they could build skyscrapers.

As you put it - it'd be "just bonkers economically".

[Guest]

Suggesting that the hinterland is located on other planets is just bonkers economically.

No, it isn't. It's perfectly viable if you have FTL drives. In Star Wars, flying to other planet takes about as long as driving to another county, and that's with a slow ship. Multi-kilometer freighters could easily make runs between Corsucant and other, agricultural planets, offloading waste and bringing in food and water. It'd be a massive operation, but in SW, it's not even worth mentioning. It just happens, in the background, moving around billions of tons of mass and even more credits. If you can have that, a city planet's biggest problem is heat radiation, and Coruscant has an issue of being Earth-like before it was covered in a city (it's in EU somewhere). I think that a realistic ecumenopolis would be built on an icy world like Mars, far from the sun, so that it doesn't overheat. You need to balance heating from the city with heating from the sun, if the latter is too high, then after building the city, you'll turn the planet into a sauna, due to greenhouse effect and all the waste heat from the city. Huge oxygen recycling plants would be needed, as well as waste processors, all powered by fusion.

Oh, and single-biome planets are very realistic. In most cases, assuming there's an atmosphere, you've got a choice between "ice cap" and "rest of the planet", unless the planet is entirely covered with ice, or too close to the sun to have any. Without atmosphere, it is, in most cases, "rocky wasteland" all over. If you're lucky, there is an ice cap. Earth-like (multi-biome) planets are rare and usually indicative of water and advanced life forms being present (come to think of it, Earth would also be "rocky/sandy wasteland", "water" and "ice caps", if it wasn't for life).

[Seret]

That's because our large cities still have space to grow wide instead of tall.

Look at the Honk Kong instead - it pretty much paved all of the arable land and inhibited natural biosfere on it's own island.

Hong Kong isn't a self-contained ecosystem. If it takes up it's whole island the atmosphere remains breathable. Crucial difference.

Ok, so let's imagine a city had grown so large that it's hinterland covered the whole surface of the globe. The ecosystem is likely to already be under severe pressure, any further urbanisation would seriously erode quality of life and economic output of that world. If this is a civilisation that's confident moving stuff around between the stars then further urbanisation would just occur on the other worlds, where there was less friction to it. It's not a matter of tech level, we don't do things because they're technologically possible, we do them because they're economically or socially advantageous. Just because a civilisation could establish a planet-wide city doesn't mean there would be anything driving them to do so. Especially when they have other much easier solutions available.

Now, I assume from your login that your a big Star Wars fan. Cool, so am I. But it's not real, and most of it doesn't make any actual sense. But hey, that's the cool thing about fiction: it doesn't have to.

[EdFred]

If we had the tech to turn Earth into Coruscant and survive, the technology to farm the entire Moon and supply Earthuscant would be trivial.

[cantab]

Something that randomly occurred to me earlier regarding Coruscant-style planet-cities: what about air pressure? Coruscant supposedly has over five thousand "levels". If one level is meant to be a single floor of a building, so around 2-3 m, then that would tally with the planet having skyscrapers that dwarf its natural mountains. Considering the tech available, the high levels could be made amenable in pressure and temperature, but then the lower levels would be too hot and too high pressure.

[Idobox]

What does a city hinterland do?

turn dirty water into clean water

turn CO2 into O2 and food

provide materials for construction and industry

And all of this can be done without a hinterland. Turning waste-water to drinking water is regularly done on military ships and the ISS, hydroponics and chemical processing can turn the CO2 into food and O2, and materials can be imported.

You can also imagine having ships carrying CO2 one way, food and O2 the other way, and the same thing for water.

Heat would be the major issue. In addition to shading and moving the planet away, a more radical solution would be evacuate heat by ships. You would need to build giant insulated ships, flll them with something with high thermal capacitance (ie water), use heat pumps to move the heat from the planet to the ship, fly the ship to somewhere cold, release the heat, rince, repeat.

Of course, you need ships that can carry more heat than the pumping and flight deposit.

Now, why would you want to do that? For the same reason people live in Tokyo, London or New York. The cost of living will be much higher than on other worlds, but the opportunities too.

According to wookiepedia, Coruscant has a population of around 1e12 by the end of SW3, while the galaxy is around 1e17. That means that roughly 1 in 100 000 citizens live there. The same proportions for real countries would make Washington 3200 inhabitants, London 640, and Tokyo 1260.

Still according to wookiepedia, there are 70 millions system with the requirements to be represented. If we assume each system sends 10 persons to represent it (including minor staff), we already end up with 700 million people, just for the senate. Brasilia, a city built mostly to be the capital of Brazil, has a population of 2.8 million, the Brazilian parliament has roughly 600 seats. If we use the same proportions with 70 million seats, we get a population of .3 trillion, roughly 1/3 of the stated population of Coruscant.

[Brethern]

What does a city hinterland do?

turn dirty water into clean water

turn CO2 into O2 and food

provide materials for construction and industry

And all of this can be done without a hinterland. Turning waste-water to drinking water is regularly done on military ships and the ISS, hydroponics and chemical processing can turn the CO2 into food and O2, and materials can be imported.

You can also imagine having ships carrying CO2 one way, food and O2 the other way, and the same thing for water.

Heat would be the major issue. In addition to shading and moving the planet away, a more radical solution would be evacuate heat by ships. You would need to build giant insulated ships, flll them with something with high thermal capacitance (ie water), use heat pumps to move the heat from the planet to the ship, fly the ship to somewhere cold, release the heat, rince, repeat.

Of course, you need ships that can carry more heat than the pumping and flight deposit.

Now, why would you want to do that? For the same reason people live in Tokyo, London or New York. The cost of living will be much higher than on other worlds, but the opportunities too.

According to wookiepedia, Coruscant has a population of around 1e12 by the end of SW3, while the galaxy is around 1e17. That means that roughly 1 in 100 000 citizens live there. The same proportions for real countries would make Washington 3200 inhabitants, London 640, and Tokyo 1260.

Still according to wookiepedia, there are 70 millions system with the requirements to be represented. If we assume each system sends 10 persons to represent it (including minor staff), we already end up with 700 million people, just for the senate. Brasilia, a city built mostly to be the capital of Brazil, has a population of 2.8 million, the Brazilian parliament has roughly 600 seats. If we use the same proportions with 70 million seats, we get a population of .3 trillion, roughly 1/3 of the stated population of Coruscant.

Why go through that trouble? set up huge artificial gravity plates and lower the gravity on them, low gravity means that the gases escape into space taking the heat with them.

[Sky_walker]

Hong Kong isn't a self-contained ecosystem.

Coruscant isn't one either. It's fully dependent on other planets - just like Honk Kong is.

The ecosystem is likely to already be under severe pressure,

I thought it's obvious that the ecosystem wasn't a concern for people covering Honk Kong island with a buildings.

would seriously erode quality of life and economic output of that world

Matter of technology and what you define as "seriously". Though As far as I remember - in lore it's quite clear that the living conditions on Coruscant were worse than these on other, "green" planets.

then further urbanisation would just occur on the other worlds

And so it did, but obviously - just like with Honk Kong - there were economical and political reasons to concentrate so much concrete and steel in once place

A capital planet of an entire galaxy - looks like a reason good enough on it's own.

Just because a civilisation could establish a planet-wide city doesn't mean there would be anything driving them to do so

It also doesn't mean that there absolutely couldn't be anything to drive them doing so - which is what you assume even despite of quite overwhelming proofs to the opposite.

Especially when they have other much easier solutions available.

So there are easier solutions to make people live away from large cities. Cheaper land, better availability of food, water, higher quality of air, lower ambient noise levels, and so on, and so on... yet here now on the earth population of large cities is constantly increasing, not decreasing.

Now, I assume from your login that your a big Star Wars fan.

Wrong assumption. My nickname got nothing to deal with Star Wars. It's a poor translation of paraphrase from my native language - made it back in a day when still learning English, and got stuck with it.

But it's not real, and most of it doesn't make any actual sense.

I know very well it's not real and tons of stuff in it don't make any sense - but this one particular part actually does make sense.

Why go through that trouble? set up huge artificial gravity plates and lower the gravity on them, low gravity means that the gases escape into space taking the heat with them.

It'd also escape more quickly than you can refill it

Edited August 28, 2014 by Sky_walker

[Sky_walker]

Something that randomly occurred to me earlier regarding Coruscant-style planet-cities: what about air pressure? Coruscant supposedly has over five thousand "levels". If one level is meant to be a single floor of a building, so around 2-3 m, then that would tally with the planet having skyscrapers that dwarf its natural mountains. Considering the tech available, the high levels could be made amenable in pressure and temperature, but then the lower levels would be too hot and too high pressure.

This should help you to answer the question: