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.

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Many things could cause people to flee to the stars, be it a flight from ruin or a pursuit

of new worlds and opportunities, but such an exodus

might be a protracted or even perpetual state around which a civilization might arise.

So last week we were looking at future types of government and this week we'll be continuing

that discussion as we contemplate the popular science fiction trope of wandering fleets with

no home world to call their own, often operating under some oligarchy of ship captains,

something called a navarchy, and we'll explore what might cause such a civilization

to exist and how they might operate.

We see this nomadic fleet civilizations in many a story, but two of the best known are

the remnant survivors in Battlestar Galatica, whose homewards were taken away by the

Sylons, a race of artificial intelligences they had made, and the Korans of Mass Effect,

whose homeward was taken away by the Geth, a race of

artificial intelligences they had made.

There are also the Eldar Craft Worlds in Warhammer 40,000, giant ships that fled

their old civilizations descent into chaotic debauchery.

...