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.nebula.tv slash Isaac Arthur

and use my code, Isaac Arthur.

If you want to build the future, he might have to leave the ground behind.

In the centuries to come, humanity might be known not for how we conquer the land, sea, or air,

without we learn to build among the stars.

For most of history, the Earth has been the only factory we knew,

bound by gravity and

atmosphere, shaped by the limitations of its surface, but orbit offers something new,

a realm of endless possibilities, where gravity, pressure, and even raw materials, can

be tailored to our needs.

Today, we're already taking the first steps into

that future, experimenting with manufacturing in the weightlessness of orbit. And while these

early projects are small, delicate fibers, perfect crystals, tiny tissues, they are the

seeds of something far greater. In this episode, we'll explore how

zero-gravity and space-based foundries could transform our world and eventually build

entirely new ones. We'll journey from the first experiments aboard the ISS and commercial

...