Hello, SFIA audio listeners.

In this month's Nebula exclusive, big alien theory,

we're asking 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.nebula.tv slash Isaac Arthur and use my code, Isaac Arthur.

In the past, we had entire civilizations

devoted to agriculture, but in the future we might have entire planets devoted to it.

As the harvest season wraps up, for those of us in the Northern Hemisphere for 2023,

I thought it might be a good time to examine

the concept of Agri Worlds.

Entire planets dedicated growing food inside larger galactic empires, such as the 20 dedicated

farming plants that supported the Imperial Capital of Trantor in Isaac Asmos Foundation series,

or the far more dystopian agri worldsworlds of the Warhammer-40,000

setting.

So we will look at this concept, what farming might look like in such vast civilizations,

and ask if there is a scientifically possible scenario where an entire planet might export

food to another world, and if so, what kinds, as well as asking what role space farms

might have in the future and what they might look like. These planets are ubiquitous in

science fiction, but often covered only in passing, the literary equivalent of driving

through the cornfields of Indiana, or the endless plains of wheat stretching from Oklahoma and Kansas

through to Alberta and Saskatchewan.

I have only seen one description longer than a few sentences, in Chris Rade's novel,

...