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Where Does The Sky End?


Where is the border between sky and space? That's what 5-year-old Matthias of Durham, New Hampshire wants to know. Alesandra, 3 of Bella Vista, Arkansas wants to know why we can't hold air. We're joined by anthropologist Hugh Raffles, a professor at The New School, and by astronomer John O'Meara, chief scientist at the Keck Observatory. And we have special scoring by cellist Zoë Keating.

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This episode of But Why is both philosophical and scientific. We'll explore what scientists know about the boundary between sky and space and the boundary between sky and land. Both can get a little squishier than you might think.

Ideas about where the sky ends and space begins depend on perspective--different scientists use different definitions. Astronomer John O'Meara helps walk us through the various ways to look at it. And while the boundary between sky and land certainly seems more firm, there are times when our experience of that dividing line can be deceiving.

We'll also learn about some of the things floating in the air around and above us--millions of insects we barely notice and didn't know anything about until the 1920s. Hugh Raffles details these discoveries in his book Insectopedia, and shares some of the fascinating information with kids here. The music of cellist Zoë Keating infuses this episode. We commissioned her to score the episode to help give our listeners yet another way to experience a changing perspective. You can find more of her music here.


Melody is the Contributing Editor for But Why: A Podcast For Curious Kids and the co-author of two But Why books with Jane Lindholm.
Jane Lindholm is the host, executive producer and creator of But Why: A Podcast For Curious Kids. In addition to her work on our international kids show, she produces special projects for Vermont Public. Until March 2021, she was host and editor of the award-winning Vermont Public program Vermont Edition.
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