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 Skillshare.

We often picture aliens is rather horrifying to look at, but the truly terrifying thing about aliens

may not be the way they look, but rather the way they think and act.

Who knows what horrible terrors await behind those 16 eyes and razor-sharp teeth?

Science fiction is full of examples of terrifying aliens, and since Halloween is coming up shortly,

I thought we would take a look at some of the more common notions and tropes of terrifying aliens,

and ask how realistic they are, as well as contemplating some ways aliens might truly

be scary to us simply due to different evolutionary paths.

Of course, aliens aren't likely look human like they often do in science fiction movies and

TV shows, or even humanoid, that's mostly a byproduct of limitations of makeup,

costumes, budgets, and sometimes imaginations.

We get all fair share of jump scares on amusement park rides where some horrible tentacular

spined abomination swings out at you when you least expect it. That's probably the closest

to what we'd expect to find rather than near human or cute and cuttly. While amusement rides

are designed to be scary,

they're not truly terrifying. For terrifying, we need to go beyond amusement park and look at alien

behavior. It is the alien mind, not the alien body, that will keep us up at night. We rightly

fear the unknown. There is nothing we can say for sure about alien behavior, we'll only know when we encounter

one and even then that's a sample size of one.

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