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.

Tearforming an entire planet is a colossal undertaking that will take lifetimes to complete.

So assuming you're that committed to seeing it through, how do you even start?

Something we talk a lot about on this show is traveling to new worlds and terraforming them,

but there's a big gap between those two.

We'll be covering the gap today between terraforming and para-teroforming, as well as bioforming,

to look at that period after initial civilization has gotten set up,

but before the planet could be considered Earth-like by any measure.

It's too much to cover on a single episode, though, so planet could be considered Earth-like by any measure. It's too much

to cover on a single episode, though, so we will be looking at building biospheres next month,

December 4th, 2024, where we'll try to look at it from a different perspective.

To make sure you get notified when that and other episodes come out, don't forget to hit

the subscribe button and turn on notifications,

and please hit the like button while you're at it.

It's a big topic, bigger than even two episodes can cover, but we'll try to get to

as much as we can today, and we'll be here for a bit, so grab a drink and a snack,

and let's get started, building a new world.

Terraforming is the process of making a planet more Earth-like, like adding water to a desert

planet, and it's one of five basic approaches to spreading humanity, or any civilization,

...