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.nebula.t.v.t.v. And use my code, Isaac Arthur.

This video is sponsored by CuriosityStream.

Get access to my streaming video service, Nebula, when you sign up for CuriosityStream

using the link in the description.

One day, strangers from a strange land may come to our world, and it is entirely possible

they'll come as friends or conquerors, bearing guns or gifts or seeking sanctuary.

The tricking part will be figuring out which is which.

For the last couple of months, we've been looking at concepts like extra-galactic sanctuaries and deep space habitats,

and why someone might live in such places and what sort of someone's that might be.

And it reminded me of a common staple in science fiction, rather than aliens coming to meet us or conquer us,

they're actually refugees looking for a place to live. The sci-fi film, District 9,

looks at the notion of an alien ship landing in South Africa in 1982 in an alternate past.

We also see this in the film and TV show Alien Nation, in which we have the alien newcomers as a refugee population in California, after their ship landed in the Mojave

desert, and we see Terran Stamp playing an alien crime boss in that movie.

In a way, it's not too different from his role as

General Zod in Superman 2, or the 2013 reboot, Man of Steel, where Zahn and his followers are

essentially refugees of a destroyed civilization. It is a reminder as we try to contemplate this topic

that aliens coming to Earth might be very much like

us, in which case they would run the gray spectrum of morality, saints and crime bosses, but that

...