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.

The only way to deal with a dangerous world is to become as dangerous as it.

William S. Burroughs.

In recent months, we've been looking at hypothetical planets devoted to a single purpose.

We have looked at hive worlds full of people or entire planets devoted to

industry. We looked at one devoted to farming or to being a fortress in wars, and these are all

purposes devoted to keeping people alive and supplied. The purpose of the planets will be

looking at today, though, of death worlds, is trying to kill their inhabitants off. So today we'll

contemplate being on an entire planet devoted to killing you from the moment you step on it

or draw your first breath. It's a popular concept in science fiction, dating back at least

to Harry Harrison's Death World series in the 1960s. Of course, tales of us surviving in harsh environments

long predates that, and lots of adventures and early sci-fi are set in distant, dangerous

jungles, or icy tundras, or desolate deserts. It was natural that we would move those

stories into space, and we see hundreds of them as settings for stories,

everywhere from Frank Herbert's classic Dune to Star Wars Frozen World of Hoth, or Jungle World

of Digaba.

Frequently on post-apocalyptic future Earths littered with mutants and techno-barbarians,

living among the radioactive ruins.

But what is a death-bold?

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