Warhammer 40k fluff thread VI: They see me Ward'en, they haten

[LCP]

I don't want to get involved in the “is the Imperium a nice place to live” conversation , but I do want to get involved in the “how many people should there be in a hive city” conversation. I'm a physicist, and we love approximating things to be spheres and cubes and what not, but even I have to disagree with assigning each population member a unit of cubic volume and just multiplying that by the population.

I think you sum it up when you say

Tokyo comparisons don't really cut it, since none of our modern cities approach the density of an arcology.

So you've got a picture of an arcology there where population density is the driving goal. I don't think that matches an Imperial hive, for a few reasons. Drop the assumption that you're trying to house a quadrillion people for a moment (to avoid circular reasoning) – what other goals might the Imperium have in building a city?

They build vast religious structures which house effectively 0 people. On strategically important worlds (and most hive worlds seem to be strategically important), they build huge fortifications. The upper spires of most hives are portrayed as palatial complexes inhabited by a few super-rich aristocrats. Most importantly, most hive worlds are tithe grade “Exacta Extremis”, so they have to produce stuff. During the Armageddon campaign there was mention of a tank factory so large that sweeping tank battles were being fought inside it.

Of course, you can bolt on correction factors to your previous calculations, and you'll come to the same conclusion – even if you say there's ten times as much space devoted to machines and walls and penthouses and factories as there is to population housing, your numbers aren't going to change by more than an order of magnitude, and you need many orders of magnitude to square your calculation with the smaller picture. But I still think that's going about things the wrong way: the manufactoriums and such aren't add-ons, they come first.

If you're constructing a hive city, the first thing you need to think about is where these centres of planetary industry are that drew so many people together. Then you place the hab-blocks around them that you need, to house their working population. Then you build the Cathedral of the Holy Worker or what have you to service their spiritual needs, and the Palace of the Guild Commercia, and a shuttle-port or three, and some big orbital defence lasers and walls. Of course, this all brings in more people, so you have to house them too; the place is starting to look a bit polluted with all this urban/industrial activity so best stack 'em inside the walls, not outside.

Over time, this mega-city is going to become the dominant economic force in the region, and more and more people are going to move there as its demand for manpower increases (and in most cases, as it poisons the surrounding land), so it grows upwards. New factories get built with the new money, and new workers are needed to make those factories go. Old structures become unsound or abandoned, and new structures get built over them. There's a cross-sectional diagram of a hive in an old White Dwarf which shows it as a layered cone: as you get deeper and closer to the centre, the more derelict/unlivable the structure gets.

The picture I get of your average hive is that most of its volume is 'dead' – killed by the weight of the city on top. You're going to have an inner cone kilometres high that is urban wasteland, underhive territories which can support only a scraggly population of gangs. The vital activity of the hive – manufacturing, habitation for the average citizen – is going on in a surface layer surrounding that core, with a gradual gradient between the two. It's like an old tree - the dead stuff on the inside is pretty much just providing a structural skeleton for the living surface to cling to.

This is just my picture, so obviously you're free to disagree. I can think of a little bit of canon support – there's that diagram, and in the FFG RPG line they talk a fair bit about Hive Sibellus being built over itself, to the extent that a lot of buildings are carved out of old broken statuary that no-one remembers the meaning of. I don't think canon support is too important here – all I'm trying to do is paint a plausible picture of a hive world with a population in the billions, not trillions. I'm not saying it's implausible that an advanced hive city could be built in an arcology fashion, with the intention being to stack as many people in one place as possible (and then your numbers would stack up fairly well); I'm just saying that I think this alternative picture also makes sense.

The Imperium as a central administration doesn't care too much about efficiency or living standards; even if it did, it's just too big to be able to implement them. What it cares about is rates of production, and there are two ceilings on that: working population, and the resources available to be exploited. If you hit the second ceiling before the first (imports/exports moving at maximum capacity for the physical size of your city, etc. - things which are mostly going to be a function of surface area, not volume), then no-one off-world is going to care how much housing space you waste. And even if it does get to the state where re-building it more efficiently seems attractive, by that time it'll be so vast and sprawling that the short-term cost would be astronomical.

I'm interested in this, by the way, because I'm trying to flesh out a hive world for my current Dark Heresy campaign. Just thinking about this enough to write it down has been helpful in consolidating some of my ideas, so apologies for the rambling post.