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.

And on a pedestal these words appear.

My name is Azamandius, king of kings.

Look on my works ye mighty and despair.

Nothing beside remains, round the decay of that colossal wreck, boundless and bare.

The lone and levelands stretch far away.

Welcome to Science and Futurism with Isaac Arthur, and I am your host, the aforementioned

Isaac Arthur, and I've been your host for nine years now as we celebrate the ninth anniversary

of our first show back on September 17th of 2014.

We'll talk about that more toward the end of the episode, but that original episode,

and its unplanned sequel some months later, we're focused on the idea that our image

of the future from sci-fi, of being a civilization of thousands of planets spread over a galaxy, was

wrong.

In space opera, humanity colonized endless worlds around yellow stars and occasionally other kinds

too, and maybe has a few other minor outposts or space stations in any given star system,

...