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 add free, plus hours of bonus content, check out

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

Stars give warmth of light to planets and make life possible, until they run out of fuel and die themselves, but could these dead stars still enable life to dwell around them?

There are hundreds of billions of stars in this galaxy, and most are smaller than our sun,

and even of those that are bigger, virtually all will expand to a red giant one day, then shook off their

outer layers and collapse inward into a burned-out husk called a white dwarf. This is the fate of 97%

of all stars, including our own, and so it stands to reason that we might want to have a

game plan for living around them. Indeed, even though most stars that have ever formed are

still alive, we still have around 10 billion white dwarfs in our galaxy already, including

over a dozen in our nearby interstellar neighborhood, out to about 30 light years. So while every

civilization probably needs to have a plan for living around white dwarfs eventually, it probably

behooves them, and us, to have a plan even sooner. We will also be exploring some new megastructures

and variants that work well around white dwarfs, and brown dwarfs too for that

matter, such as strip wards or solar bracelets. So our journey today is going to take us to the heights

of mega-engineering and the depths of deep time, which means we'll be here for a bit, and a drink

and a snack might be a good idea, and don't forget to hit the like and

subscribe buttons while you're at it.

Now our goal today is not to rehash the basics of what white dwarfs are or how they

come to exist.

I think most people do know that, but a lot of times that's about where that knowledge

...