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.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

You've made it to a new world, but how do you make a living when Earth is 100 light years away?

We often focus on the engineering challenges of getting people safely to another planet,

an even bigger challenge of making that world livable once they arrive.

But there's a more subtle, equally vital question at play. How do you convince you

when to go in the first place? How do you build a life and an actual economy? There's no

Walmart on Mars, no Amazon Prime at Proxima Centauri, and no corner store when you run out of coffee.

Even for the short hops around our own solar system, say Mars, series, or the clouds of Venus,

they are big, unresolved questions about how interplanetary trade would actually work.

What goods would flow? Who pays the bills? What currency do you even use?

And when it comes to interstellar colonies or ideological breakaway groups, the problems get even more complex.

Trade might be minimal, or even deliberately avoided. Some colonies would be designed from the outset as self-contained economies, autarkies in space.

They'll need to grow food, build infrastructure, and organize labor, without expecting a single shipment from Earth, ever again.

We can imagine futuristic technologies softening the blow, settled spanning the journey in cryosleep, or ultra-long-lived crews returning

home after a profitable tour of duty. There are paychecks swollen by interest and relativistic

time dilation. Others might come later on other ships or awaken only after the hardest work is

done, arriving to join a colony already underway. But even then, you left with a core dilemma.

How do you jump start to an economy when there's nothing to buy, no one to sell to, and your only

customer might be the mission commander? That's the question we'll be exploring today,

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