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.

Imagine a scale where civilizations grow as vast as galaxies.

Today, we're exploring the Kardeshev Scale, the cosmic ladder, where power and progress go hand in hand.

Today we'll be exploring the Kardyshev scale, the system originally created for astronomy and steady efforts, the search for extraterrestrial intelligence that has since become the

framework for discussing advanced civilizations, potentially including our own.

These civilizations can become almost inconceivably vast.

To imagine the power of a full K-1 civilization, think of an entity capable of deploying

a billion troops into a conflict if necessary.

When we consider a Cardishv II civilization that harnesses the entire energy output of a star,

we are looking at the resource equivalent to a billion planets.

A Kartashev 3 civilization, which spans an entire galaxy, might view planets the way modern

nations view paper clips and could engage in conflicts where stars

are weaponized and planets serve as munitions.

These are stellar empires that don't measure soldiers in the billions, they count generals

and admirals in those numbers, or even in the trillions and beyond, and the same applies

to other professions.

With a billion times the population, such a civilization would have a billion Newton's

or Einstein's, and could fill a planet with mines like Shakespeare or Van Gogh.

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