Based off of this deleted question: Why and how would a completely urbanized city-planet exist? Related:

  • $\begingroup$ I don't think this qualifies as an asnwer...so comment it is. I would suggest that it doesn't...there simply isn't enough resources on a planet to get away with this, even 'air' would be considered an invaluable resource. If you are looking into the one massive city complex setup, I'd suggest the Dyson Sphere is a far more realistic expectation of what it would look like. $\endgroup$
    – Twelfth
    Commented Oct 4, 2014 at 0:41

5 Answers 5


In general, I would advise not to assume that centralized systems will be prominent in the future.

The trend toward centralization in the late 1800s through the mid-1900s was largely a result of the network effect in analog communication technology giving an advantages to vertical hierarchal organization. It pretty much reached its limits by the 1970s at the latest and died utterly with the digital age. It keeps on in government largely by inertia and governments ability to force people to support it no matter how dysfunctional it becomes.

All the action in systems theory today is in decentralized systems like swarms. I wouldn't look to centralized systems of the past century as models for the future. That would be like someone in 1775 assuming that the America of 2014 would be some form of Monarchy because almost all government up to then had been monarchies.

A strong government would naturally be required, as the cost, in resources, time, and intelligence, to maintain such an enormous construction would be astronomical.

Even if you look at modern cities with notionally strong centralized governments, like modern day New York, you will see that the vast majority of operational decisions remain private e.g. who buys and sells what property, who pays for most construction, how the businesses who directly or indirectly pay all the taxes operate. Government remains a relatively thin gloss on top of the private sector. The private sector exist a priori to and without government but government cannot exist before and without the private sector.

A strong centralized government would only be absolutely necessary if the city planet had no actual economic rationale and the government had to forcefully direct the allocation of resources to and within the city to prevent the spontaneous flow of resource away from the planet city.

This is even more paramount if the city extends greatly both above the natural surface and into the ground, as they would be expected to do so once all horizontal space is occupied.

I don't see why. Skyscrapers are and have historically been completely private constructions. Even within single buildings, you can have internal private property. This is the concept behind condos and coops.

Could the city-planet ever be privately owned, or would it have to be controlled by a centralized body?

If the entire planet was owned by a single entity, it would function internally as if run by a non-representative government. Corporations operate internally much like governments (more accurately modern government administration is are modeled on corporate operations) which is why corporation often stop functioning and go out of business.

A more interesting question is if such a city could operate primarily with billions of private owners using just decentralized, voluntary, private decision making and exchanges. Clearly it could.

As long as the planet city had a functional/economic reason to exist, it could operate by decentralized spontaneous cooperation. The great cities of the English speaking world e.g. London and New York, grew to the largest cities of their day in a decentralized manner and only became centralized as they declined in relative dynamism.

Just because people are crowded together and very interdependent doesn't mean they can't exist without Hobb's Leviathan threatening them constantly. Property systems work very well to allocation resources on a voluntary basis.

Ownership means the ability to make decisions about the allocation of a resource. Property system manage the allocation and transfer of that decision making authority. Property system can allocate any resource, not just land area.

For example, in a giant planet city arcology, a valuable "resource" would be load bearing structures. Anybody wanting to build a new structure would have to build over an existing structure. To build over, you would need to put load on an existing structure. The ability of the existing structure to handle the load or be adapted to do so would be very valuable and so could be made a property. People could sell the load bearing capacity of their property just like we sell off water or mineral rights while we continue to live and farm on the land surface itself.

Water, air, power can all be managed by property systems without centralized coercive government.

It's even quite possible that a centralized government can't scale beyond managing systems of a certain size and complexity. Centralized government by definition means fewer decision nodes which means fewer people making more of the decisions. Since individuals can only process so much information per unit of time, as the system managed gets larger, the decision making process gets slower and slower. In a vast planet city, the decision making process might get so slow as to cause the system to be effectively paralyzed. (Corporations stared decentralizing in the 1970s and many argue that large modern cities have already reached the point were they must decentralize of implode.)

By contrast, decentralized system have a huge number of nodes and make decisions in parallel. They can scale massively and get faster the larger they become. Biological systems work this way and they are far more complex than a city.

Could crime even exist if such an extremely strong local government is required?

Strong centralized governments tend to foster crime, not suppress it. When governments have no competition, they have little incentive to be either efficient or effective. Centralized governments are more prone to corruption both from within and from external criminals. Centralized government tend to evolve to see the world as divided between not the lawful and unlawful but those within the government and those outside the government. Those inside the government don't care if those outside get mugged.

The Soviet Union had shockingly high levels of even common street crime dating back to time of Lenin and they never managed to control it even though they were a police state. Their police states focused on political threats, usually from their fellow ideologues, and ignored prosaic crime. Likewise, the Russian mob didn't just spring into existence when Communism fell it was around for a long, long time. It survived by fostering corruption within the Communist regime itself. Similar patterns existed in all totalitarian states.

You can see the same effect in the complex of big city political machines, unions and mobs that highjacked many US cities in the 1920-1970s. Organized crime was massive and eventually, unorganized crime grew out of control as well even as the local governments got proportionally larger but more effective at the same time.

How would terrorism be prevented from taking out sections of possibly kilometers-high load-bearing populated structures?

The bigger the system, the more robust and hard to disrupt it will be. It's been said that you couldn't might not be able to destroy Hoover Dam even with a nuke and couldn't even dent it with any plausible amount of conventional explosives. The support structure for a kilometers high structure would be similarly massive and hard to destroy.

A more likely target would be the informational systems that would control power, water and air. A planet city would have no natural buffer left and would function more like a spaceship. The easiest way to kill a lot of people would be turn off their ventilation.

Again, a decentralized system would be more robust. In the early days of electricity before it was socialized, there were often lots of redundant cables strung all over because many different companies each supplied power on their own cables. Sounds chaotic and wasteful and was to some degree but on the other hand, such a system made a city and region wide blackout impossible while they occur fairly often with the "efficient" centralized system.

In a planet city where interruptions in power and air could be lethal in mere hours, it would be suicide to have a single, centrally controlled system. One clever terrorist could bring down the entire system for billions. A tangled chaotic system of private suppliers of power and ventilation would be far safer.

As much as we twitch about our high technology systems, they are arguable more robust than their precursor technologies. For example, it inconceivable that a major modern city would simply burn to the ground but massive fire routinely destroyed major cities up until the late 1800s when concrete and steel replaced wood. The great Chicago fire is just the best know of several major fire that destroyed big swaths of several major US cities. Fears that enemy agents and anarchist would burn down entire cities where quite common and it was in fact tried. Had they known more about how to set fires, they might have succeeded.

Imagine people a 150 years ago contemplating a modern skyscraper. They would assume that assume it that, even if it stood, it would likely soon burn to ground. After all, it would be filled with wood, open flames would provide heat and light, fire suppression systems were a bucket of water and fire resistant materials except asbestos unknown.

We're probably in the same situation when we try to imagine a future system like a planet city.


Trantor, the capital world of the Galactic Empire in the novels from Isaac Asimov, is completely urbanized and (citing Wikipedia)

To support the needs and whims of the population, food from twenty agricultural worlds brought by ships in the tens of thousands, fleets greater than any navy ever constructed by the Empire.

So the answer to the question is that it is supported by external food.

Other kinds of support like Police and Military are just like any other place: if the Govern has the monopoly of violence, as it should be, it simply needs to continue being that way.

  • $\begingroup$ But as in any complex society, the government will never effectively maintain that monopoly on violence (and "as it should be" is open to question). This opens innumerable doors to plot devices involving a super mafia, a Metropolis-like underworld/overworld society, senator/mafia-king/police-generals contesting with each other at a gangland level just below catastrophic real war, etc. It wouldn't be a pretty place, it would be similar to our large cities today: full of lots of unnotable things, a few terribly powerful ugly things and a few remarkably influential beautiful ones. $\endgroup$
    – zxq9
    Commented Oct 12, 2014 at 0:50
  • $\begingroup$ I've always assumed something similar in the case of Coruscant. The amount of land area needed to grow food for a densely populated city is great. But there are all sorts of good reasons for one. Increasing productivity returns to urban scale is one of the most universal and well documented economic phenomena in existence. $\endgroup$
    – ohwilleke
    Commented Oct 25, 2016 at 7:24

How would a completely urbanized city-planet be maintained?

In general, I think that an urbanized city-planet tends not to be a practical idea, except perhaps in certain circumstances which would also determine specific answers to the question. You seem concerned with crime and terrorism, and certainly those could seem like issues, though I would think they would be less difficult than the physical and environmental issues. But I think it's very difficult to answer generally without knowing many more specifics.

Could the city-planet ever be privately owned, or would it have to be controlled by a centralized body?

Since ownership is an invented concept, I would say there is no real obstacle to this. It just requires people to agree on an ownership system that accepts it. I'm not sure what problems you are anticipating, or even whether you mean one person or entity owning the whole planet, or the planet having much of it owned by many different people. If you mean the latter, I would expect that real estate ownership, as on earth today, often doesn't involve great freedom from the law nor from government control.

Could crime even exist if such an extremely strong local government is required?

Yes. Keeping the planet and life on it working are immense problems, but not the same problems, though some solutions to the practical problems would perhaps also help a lot with crime control problems. For example, the lower your population, the less work and material required to maintain life support, and also the fewer people to keep in line. Alternatively, the solutions might not lend themselves to crime control: If the reason the planet works and makes sense has a lot to do with having a large population which contributes to the maintenance of the planet somehow, it might not be compatible to try to track and control them all - some solutions might even require an abundance of lawlessness, or at least a wide range of jurisdictions with different laws, in order to work. In any case, I would expect that there would still be a range of regions with different levels of law enforcement.

How would terrorism be prevented from taking out sections of possibly kilometers-high load-bearing populated structures?

There are so many possible answers to how a city-planet might exist and what it might be like in the first place, that no one answer could address this. I would say that realistically, long long before any society would even begin to really consider the strange prospect of having a city-planet, that they would probably need massive advances in mental health beyond where we are now, that would tend to detect and defuse people who would do something like that. In Sci Fi examples such as Asimov's Trantor, or Lucas' Coruscant, they had very capable police and security, and perhaps very strong construction and good scanners for devices capable of such attacks. It wasn't enough in either case to prevent catastrophes (see even Anakin and Obi Wan crashing a warship onto Coruscant).


There's at least two completely different scenarios which would drastically affected how it was managed.

  • The urban environment develops over time like a megacity. This probably leads to:

    • privately owned land
    • taxes and large public sector
    • crime and police
    • probably pollution
    • supplies of everything comes in by the local equivalent of road and rail (perhaps space elevators?) and certain things are very expensive, probably including bulk consumables such as food and fuel.
    • if the supply chains prove inadequate then you end up with either a ghost town or people starving (similar to cities under siege such as WW2 Leningrad).
    • if certain things can't or won't be allowed in then you get black markets and smuggling (perhaps even odd situations like cars being smuggled through tunnels into Gaza)
    • It needs a powerful local economy to provide employment for massive numbers of tertiary sector workers, and/or a short travel distance from other planets.
    • generally everywhere looking a look like middle of New York, London, Tokyo, Beijing etc.
  • An urban environment designed to meet a specific need.

    • Single employer (similar to military bases, oil rigs, scientific research bases, the Death Star etc)
    • Or not designed as a society, could be like a giant cruise ship/holiday camp or even something like a hospital or prison
    • Whatever it produces/consumes has to moved on and off the planet, so massive focus around spaceports/space elevators etc (unless the planet controls a space-based industry such as mining or spaceship construction).
    • Crime is dealt with by eviction, termination of contract, court martial etc
    • Resources are centrally allocated. No markets or competition.
    • Company rules replace laws or social norms.
    • Generally everywhere looking like a factory or military base. No personalisation or individuality.
    • Maybe a temporary installation, or the workers/soldiers/inmates might be temporary

You could probably look to the Hive Cities and Hive Planets from Warhammer 40K lore to get a good idea of how to administer and support such an immense city-state.

Food supply

If your city isn't surrounded by vast agricultural lands, or have internal 'agri-towers' (think vertical farmland built up like skyscrapers) then you're going to need a strong external food supply, like a nearby agri-world to support the population. This can lead to two situations:

1) food supply is local in towers or farming plots just outside the city, and many people receive it from many sources. Smuggling and food theft become serious issues as people look after themselves over the collective. One group may sabotage food supply to hurt others and fights for scraps are commonplace

2) food supply is external and a strong governmental body (or corporation) rations the food coming into space-ports to ensure everyone is fed. Of course, inevitably, the rich get more, the poor less and bribery and corruption run rampant in the rationing centers (which I imagine as vast militarised fortresses protecting the resources from the starving mobs)

Maintenance of infrastructure

Maintenance issues would also be a serious problem, when your cities are a kilometre or two high, and packed solid like say, beijing, a lot of traffic is moving at all times. Any modern material would quickly crumble under its own weight or under the constant stresses of its inhabitants. before you even start building this city a big leap in construction techniques or materials are needed. Depending on tech levels you'll either have a city-wide construction site constantly repairing, replacing and shoring up buildings as they fail, or some self repair function could be build into the infrastructure itself (piping full or repair nanites, automated robotic construction crews, etc). You could also have a third route, just keep building atop the crumbling ruins beneath in endless layers of city-scape

Law and Order

Let's take a small scale (compared to this at least) city like Medellin. There are already large sections of the city the police will not go into without military backup. And that's a simple 2d (ish) city spread out over a large area. Now if that were to be transformed into a towering mass of skyscrapers, and population density increased even further, the criminal underworld could effectively gain control of large portion of the mega-city if living condition were low. And lets be honest, the sheer size of such a city would means large sections will be overlooked, or abused by the governing body. Any police force that attempts to control such a place would need to be very heavily armed and armored, and have a brutal set of tactics. That, or you would need to abandon sections to cartel rule and trust they wont bring the whole city down around everyone's heads.

Environmental impact

With such a large portion of the planets surface taken by urban areas, the environment will be severely compromised. Even in our modern level of urbanization there are concerns over sustainable levels of rain-forest to ensure oxygen supply. This would be a serious issue if your source of food is external, as not even the agri-towers could assist with air quality control and oxygen liberation from carbon-dioxide bonds. Take Japan or China as a small scale version. They have very large industrialized cities, and air quality is below acceptable human levels in some sections. Now scale it up, and you have a serious environmental catastrophe. Now of course, you could have some sort of large scale air purification systems (these are already in R&D today) to cut down on airborne contaminants, but there is still industrial runoff in water tables, that poor abused ozone layer, and lack of ecological diversity. If your entire planet (or a large majority portion) were to be city, then it would be a very poor place to live, from an environmental perspective.


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