Hey, it's Ira Flato, and this is Science Friday.

Today on the show, Earth's trusty sidekick, the moon.

We think that the Earth and the moon mixed so completely that they are now basically the same

chemically. They're kind of twins in a way.

Thank you. basically the same chemically. They're kind of twins in a way. Summer is such a great time to look at the moon. And you know what? The moon is not just a big

rock. The moon is responsible for some of the most important processes here on Earth.

Not just the tides, but migrations, reproduction,

circadian rhythms, and a whole lot more. Author Rebecca Boyle makes the case for our space

sibling in her book, Our Moon, How Earth's Celestial Companion transformed the planet,

guided evolution, and made us who we are. We talked to her last year when her book came out,

and this month, the Sci-Fry Book Club, is reading our moon. Rebecca, welcome to Science Friday.

Thanks so much for having me. All right, you, this is like a love story. You write about the moon,

right? So I'm going to close my eyes, and I want you to take me to the moon.

We've traveled.

What do I see?

Well, we've gone about a quarter of a million miles, and if you're on the surface and you've landed, and it's been a few minutes, hopefully, there's not dust kind of settling still around you in microgravity.

You weigh about one sixth of what you weigh on Earth.

It is completely silent, except for maybe the beeping of your life support system in your

spacesuit or your spaceship.

And there is nothing in front of you but a landscape that only a geologist would love.

It's mostly white, mostly gray, but there are flecks of color depending on how the sun

hits the rocks and maybe how the angle of the sun is falling on your spacecraft or what's right

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