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.

This episode is sponsored by Brilliant.

We often talk on this channel about wondrous megastructures that will house countless

billions and factory complexes that will dwarf our plant's entire industrial output.

But it makes you wonder, who's going to maintain all that stuff.

Something often overlooked in building projects is that in general their maintenance and upkeep

is rather staggering. Anything you build will cost you at least as much to maintain it for

a generation as you spent building it,

and even more if you are lax on maintenance and something breaks.

I'd imagine everyone here has experienced that wonderful shock of getting a repair bill

and groaning.

Should you be a true glutton for punishment, the public and private sectors afford countless

opportunities to stare down at a budget with grim certainty that the tax Glutton for punishment, the public and private sectors afford countless opportunities

to stare down at a budget with grim certainty that the taxpayers or shareholders will not

be best pleased with the news you will be sharing with them.

Left to themselves, stuff breaks down, but it does so a lot faster when being used, and

in practice just from being in

proximity to our civilization.

And we'll see that remains true even in space, where by default you'd expect the vacuum

...