This rapid expansion, he warns, will inevitably spark interplanetary conflict across the solar system.

LEX FRIDMAN: Do you think if humans colonize Mars, the dynamic between the civilization on Earth and Mars will be fundamentally different than the dynamic between individual nations on Earth right now? Like, that's a thing to load into the simulation we're talking about.

ADAM FRANK: If we settle Mars, it will very quickly want to become its own nation.

LEX FRIDMAN: Well, no, there's already going to be nations on Mars—that's guaranteed. Once you have a million people, there's going to be two tribes and then they're going to start fighting. Right? And the question is interplanetary fighting—how quickly does that happen and does it have a different nature to it because of the distances?

ADAM FRANK: Are you a fan of The Expanse? Have you watched The Expanse? Great show. Because it's all about the—I highly recommend it to everybody. It's based on a series of books that are excellent. It's on Prime, six seasons, and it's basically about the settled solar system. It takes place about 300 years from now, and the entire solar system is settled. And it is the best show about interplanetary politics. The first season, actually, Foreign Affairs said the best show on TV about politics that takes place is interplanetary.

I think human beings being human beings, yes, there will be warfare and there will be conflict. And I don't think it'll be necessarily all that different, you know, because really I think within a few hundred years we will have lots of people in the solar system, and it doesn't even have to be on Mars. We did a paper where we looked—based on CU, I wanted to know about whether an idea in The Expanse was really possible. In The Expanse, the asteroid belt, what they've done is they've colonized the asteroid belt by hollowing out the asteroids and spinning them up and living on the inside because they have the Coriolis force.

And I thought, like, wow, what a cool idea, and when I ran the blog for NPR, I actually talked to the guys and said, 'Did you guys calculate this, see whether it's possible?' Sadly, it's not possible. The rock is just not strong enough. If you tried to spin it up to the speeds you need to get one-third gravity, which is, I think, the minimum you need for human beings, the rock would just fall apart, it would break.