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 ad-free, plus hours of bonus content,

check out go.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

This episode is sponsored by Audubbill.

So much of our discussions of the future here on this show and elsewhere assume our grand

destiny out among the stars, but what if we were wrong, and that glorious future on the horizon

is merely a mirage?

A few months back, I asked our audience over on our Reddit group, R-slash Isaac Arthur, for some episode ideas, and it was so many good ones that I

decided to take five of the most upvoted and put them on our YouTube community page for a poll,

and the clear winner was today's topic. What happens if we cannot

leave Earth? One of the things I tend to be best known for is for talking about how to get us

off Earth and to new planets, so I was a bit surprised by that being a topic folks wanted me to

discuss. Of course, another thing I tend to be well known for is being pretty upbeat about humanity's future,

and as we'll see today, even if we cannot get off Earth, that doesn't make for a bleak future at all.

We don't really see a distant future on Earth being discussed very much.

Sci-fi in the galactic setting rarely does much here in favor of strange new worlds, and Earth tends to

either be the distant capital of some stellar empire, or a distant memory of a world long

since destroyed. When we do see Earth as a centerpiece of such stories, it is usually the

dying Earth saga, inevitably dystopian stories set in an exhausted planet, which is either spurned

by its distant colonies or unaided because they have the same exhaustion, dead, mined-out planets

around dying stars, and Earth, a fading ember waiting to die by fire or ice.

...