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 add free, plus hours of bonus content, check out go.nebola.tv slash Isaac Arthur and use my code, Isaac Arthur.

The mutant dream.

Every age has its fantasy of sudden transcendence, and ours was born glowing green in the

shadow of the atomic bomb.

When the world foresaw Hiroshima in the mushroom cloud, it also saw the dawn of a new mythology.

Radiation is both destroyer and creator.

From the Incredible Hulk, blasted by Gamera's, to Spider-Man's radioactive bite, the Fantastic Four bathed in cosmic light,

and the teenage mutant ninja turtles swimming in toxic ooze. The mid-century imagination found a

strangely hopeful horror in mutation. Science was changing everything, so why not us, too?

But in the real world, evolution works on patients of eons, not comic book seconds.

Mutations are the stuttering misprint in life script, most of them neutral, meaning harmful,

and only a rare few helpful.

They don't turn accountants into superheroes overnight.

They turn fin tips into fingers across deep time.

Still, the mutant myth endures,

uses speaks to our longing that any moment we might wake up transformed.

Yet if evolution can make bacteria into brains, why not an X-Man?

That's the question we'll test against the hard math of biology and the soaring hopes of fiction.

What evolution really does, in science, a mutation is simply a change in the genetic code.

One misplaced letter in life's four-character-Gatica alphabet, most slip by unnoticed,

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