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.

We tend to think of stars as fairly straightforward things.

Big balls of glowing gas that sit in the sky and warm the plants around them.

But the universe, as usual, refused to keep things simple.

It offers us everything from dim red embers that were outlived galaxies

to mighty giants burning a million times brighter than our

sun, two of the remnants left behind when those giants finally blow, white dwarfs, neutron,

stars, and black holes.

And as we discovered in earlier episodes, those so-called dead stars often turn out to be seen

the most valuable real estate in the cosmos, producing cleaner power,

denser environments, and far greater engineering potential than any living star could ever provide.

This episode got written out a bit of a whim when my son asked me about the Christmas star,

which one is the night sky and who live there, and in my somewhat rambling reply,

I mention options folks have suggested over

the years, which includes a Nova, when a white dwarf absorbs a bunch of matter and brightens me

thousand times over for a while. His reply was that probably no one would live there, and I had to

stop myself, because there was actually a lot of reasons to live near white dwarfs or red giants,

even Novaice.

This episode isn't about that hypothetical star, but I thought we'd scheduled as a bonus episode right for Christmas as an extra one. My son's gift of inspiration to me and my gift to you,

...