Hello, SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asked at 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 are finally learning how to weave the rope.

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 fact, 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 launches 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 Aqueduct, the Transcontinent Earth's surface into the black of space. And like all grand engineering projects,

whether the Roman Aqueduct, 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're hauling hundreds or thousands of tons to geostationary orbit each day, suddenly

habitats, solar farms, shipyards, and even moonbound transports, not only practical but commonplace.

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