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 add free, plus hours of bonus content,

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

This episode is brought to you by Brilliant.

Imagine living on a world where you could see all the story majesty of space,

but it was denied to you by firestorms in the sky in a constant rain of meteors.

Now, imagine that world was Earth.

So today we are going to be looking at Kessler syndrome, a cascade effect in orbit of a planet

that clutters it up with dangerous hypersonic debris, and discussing how that can happen,

what you can do about it, and the impact it would have on a world.

In many cases, this impact will be fairly literal, too.

A little while back, one of our regular editors on the show, Jerry Gurne, suggested to me that we might do an episode looking at how

Kessler syndrome might happen naturally in orbit of a planet, and if that might make civilizations

native to such worlds unable to ever pursue space colonization.

I instantly leapt on the idea and put on the schedule, but it reminded me that I've been meaning for some time to do a Fermi paradox episode on various scenarios that might keep a

technological species planet bound, like higher gravity or thicker skies or several other

options, and so we will be doing a companion

video to this one, focusing on those other options for this weekend's sci-fi Sunday episode.

As always, make sure to hit the subscribe, like, and notification buttons for alerts when

that and other episodes come out. Today, though, while we will discuss that Fermi paradox case

of Kessler syndrome, natural or artificial,

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