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. In this episode from 2020, 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. Download our learning guides: PDF | Google Slide | Transcript