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.

We often dream of climbing to the heavens, but now we're finally learning how to weave the road.

The Vision of the Space Elevator

For decades, the idea of a space elevator was pure science fiction, a vertical railroad to the stars, grand, elegant,

and utterly impractical. But science fiction has a habit of becoming science fat, and the last

few decades has seen a quiet revolution in material science that may turn this dream into

a pillar of our civilization. We've looked at this dream before, first in our deep dive on

strategies and current progress, and again we explore the economics of getting it built.

But today we're pulling all those threads together and following the ribbon from Earth to orbit,

from lab to launch. A space elevator promises to replace the roar of rocket engines with the hum of electric

motors, the flash of ignition with the glint of sunlight on a ribbon, stretching from

Earth's surface into the black of space.

And like all grand engineering projects, whether the Roman aqueducts, the Transcontinental Railroad,

or the internet, it's not just about getting from point A to

B, it's about changing what A and B even mean.

Because a space elevator isn't just a new way to get to space, it's a foundation for

building in space.

Once you are hauling hundreds or thousands of tons to geostationing orbit each day, suddenly

habitats, solar farms, shipyards, and even

...