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 add 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.

We often imagine a future in which the moon is inhabited, with domes and outposts scattered

around its surface, but what does a truly developed and colonized moon look like a thousand

years from now?

So today we are returning to one of our favorite places in the universe, our nearest neighboring world, our own moon, to contemplate the idea of a late-stage colony of the moon

when it's reached populations as high, or higher than the Earth itself currently has.

We're going to ask what the moon would be like if it was home to many billions or

even trillions, and what pathway might lead to it becoming a single, massive, worldwide

mega city, what we call a Yukuminopolis.

This is not our first time visiting the Moon here on SFIA.

I try to get an episode in about the Moon and Mars each about once a year or so, and for

the Moon we began with moon-based concepts back in early 2016, then industrializing the

moon, battle for the Moon, Moon, Industrial Complex, Moon, Crater Cities, returns

the Moon, and then last, returned to the Moon and then last year,

Mars first versus Moon First.

In all those episodes and as side topics of many others, we've discussed how to get a

base on the Moon and grow those to be real cities and colonies, and some of the possible

long-range fates of our Moon, how to make the moon a titan of industry fueling

...