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.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

We usually go for about an hour, so you probably want to grab a drink and a snack,

though we'll take a break about halfway through too.

With all that said, welcome and let's get started. Good afternoon, everybody, and welcome to our monthly live stream Q&A for January 2021.

We'll get to your questions in just a moment, but you may have noticed,

as I mentioned, coming into this procession for the day, Sarah, my wife, who usually asks the

questions, is not going to be here today. We're instead going to be joined by my friend

David Thomas, who will be reading off the questions as we go. And we'll go ahead and get started.

Yes, I'm certainly not as good looking as Sarah is,

so I apologize to your audience, but thank you so much, Isaac, this is really exciting. So,

Isaac, your first question. My question is, could you explain or go deeper into sci-fi or

interstellarship crew compositions? Information about that topic is of course very scarce, but I would like to hear your

opinion on it. How big would they need to be? What are the numbers like? Like in Star Wars or in

40K, they seem way too high, though. One of the things you have pop up a lot in science fiction

is the ships are either very small like the size of a bus or they

are the size of a state or a city. And there's some amount of accuracy of that. The big reveal

on the, you know, the Star Destroyer in the original Star Wars New Hope episode for, it just rolls

on the screen. It's huge. And that franchise, they actually had the crew compliments about

right. They are talking about like tens of thousands of people on more,

...