- Mike Massimino (pictured) must take to swimming before he can take off to outer space.
- George Church tests his own strength of will as a human-guinea pig for science.
- Sylvia Earle explores the ocean's depths as a pioneering aquanaut.
Hosted by Adam Gopnik with additional hosting from Jay Allison.
Learn more or listen again to this week's episode.
Photo by Jason Falchook