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.

The Sun is a lonely star, it's many planets millions or even billions of miles away,

and we're no kindred star within trillions, and yet many stars dance together eternally,

in binary or even trinary pairs, and we may come to live on planets with two or even three sunrises

one day.

So today we'll be looking at the habitability of binary star systems and trinary or

multi-star systems too, along with how and why we might colonize them.

Now we used to say that most stars were in binary or multi-star systems, so the issue of colonizing

them if they might have habitable planets seem pretty important.

But we have since learned that's not really the case.

In astronomy we disproportionately see the great big stars, which have great big gravity

wells, and they are far more likely to have formed with a binary partner and kept that partner,

or indeed partners, as we can't have triple and quadruple star systems or even more, and as we

talked about last month in primordial planets and multi-planetary empires, most stars

forming clusters and slowly get those perturbed apart as they wander around the galaxy and

have bigger members detonate as supernovae.

Our episode today is more on binaries and trinary systems though.

Also while we're not fixate on using the classic definition of a habitable zone

or gaudilocks zone to mean the reach amount of star in which plants can have surface

...