Hi, you're about to get smarter in just a few minutes with Curiosity Daily from Curiosity.com.

I'm Cody Gough. And I'm Ashley Hamer.

Today you learn about how we doubled human life expectancy in the last 150 years with best-selling author Stephen Johnson.

Then you learn about impossible quasi-crystals that were formed from the first nuclear

detonation.

Let's satisfy some curiosity. It's no secret that human life

expectancy has made big increases in the last few centuries and they didn't happen

by accident. Today's guest is going to tell us how our longer lives

are a result of incredible accomplishments in science and public health.

Accomplishments that, by the way, we hardly ever notice.

Stephen Johnson is the best-selling author of 13 books, along with this latest entitled

Extra Life, a short history of living longer.

We started our conversation by asking him why he wrote this book.

There's a funny thing about progress in health and medicine

that makes it different from other forms of, you know, technological progress, right?

So you can look at your smartphone or you can look at a skyscraper or a satellite and say,

hey, look, I can see this tangible object

there in front of me that is a sign of progress. But with health, particularly

as it relates to the length of our lives, the progress is actually measured in non-event in a weird way.

It's measured in things that didn't happen. So the smallpox infection that you didn't die of when you were

two because we eradicated smallpox from the globe or the cholera infection you didn't get from drinking water because we chlorinated drinking water 120 years ago.

Those are all things that we don't tend to think about

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