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.

In the future, we may have technologies sufficiently advanced that they are indistinguishable

from magic, but could those civilizations also be indistinguishable from primitive ones? Stone Age, Bronze Age, Iron Age, Steam Age, Space Age, we sure do like our ages.

And we often define our history around a given piece of technology that seems critical to that era. But what about technologies that don't fit into an era and yet remain in use?

Or which would imply a more primitive era and yet exist in a more technologically advanced one,

as we often see in science fiction, but sometimes even in our real history.

These are what we call anachronistic technologies,

ones that seem out of place for the time, but we also wrap them into developments that

might have occurred had some other technology not been invented. We see this in cases like

Steampunk, where the steam engine technology that ran trains and factories

the 19th century saw far wider and more creative uses. We wonder what might have

happened if a civilization had run only on steam engines for a few centuries, or if some

great empire like Rome had discovered that technology at its height, or another like firearms.

Often in fantasy we have worlds that never discovered firearms or steam, so as remained locked in

the medieval era indefinitely. Indeed, fantasy works often have quite the mishmash of

anachronistic technologies, including many that are post-medieval.

We also see it a lot in science fiction, folks in an era of advanced technology riding

around on horses, while they've got anti-gravity levitation and cheap interstellar space travel,

or using swords and other melee weapons, or sidearms that look flashy

...