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

Good afternoon, everyone, and welcome to the SFIA monthly live stream Q&A.

We'll get started in just a moment, but go ahead and start getting your questions in the chat

window so our moderators can start relaying those to me as soon as we start.

Please try to keep the questions concise and watch your spelling and try to be polite to

others in the chat.

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 last live stream for the year.

We're getting started in just a moment as we get questions ready.

We have a few people away for the holidays, so we're kind of going to be running things as we we can so there may be a few technical witches we get started up here as usual my wife Sarah will be asking us our questions try to get them posted

into the live stream chat and I know it's John Michael Gordio is here today hey John

and whereas we get started here just go ahead and post those in the chat, try to make them

as pronounceable as possible.

Well, our first question today is coming from Chris Leach, and he says, hey, Isaac, hope

you had a Merry Christmas, wondering what your thoughts are on the Biosphere 2 experiment and

the challenges of maintaining a small closed-loop ecosystem. How can we overcome it?

...