Hello SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asked at the reason alien civilizations might be rare is because most aliens are huge.

To hear it and every episode early and ad-free, plus hours of bonus content, check out

go.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur. This episode is brought to you by Brilliant.

One day humanity might not just have homes that stretch up into the heavens, but farms and

forests which rise into the sky too.

So today we are going to be looking at alcology design, and we have to start by asking

what alkologies are.

This is trickier than it sounds, because archaeology is a concept that's crept into public awareness

with two parallel but distinct meanings.

The first is the original meaning where our ecology is a portmanteau of architecture and

ecology, coined by architect Paolo Salieri, who conceptualized it as essentially communities

that were mostly self-sufficient and sustainable.

But the definition popularized by science fiction writers has been more like a very large building

that is a city unto itself, complete with farms and factories and living spaces.

As is always the case with fiction, peaceful and prosperous civilizations tend to make

for boring stories, and giant super buildings that dwarf any skyscraper obviously haven't

appealed to sci-fi authors.

So I think the view of them as mega skyscrapers is probably the better known one.

Nonetheless, a more originalist view of them is probably to include any city or town

that is at least moderately populous, mostly self-sufficient, but not techno-primitive.

Portrayers can run for the not-quite utopian, in which an impeccably engineered and maintained

...