Sean Carroll in Preposterous Universe:
It’s hard doing science when you only have one data point, especially when that data point is subject to an enormous selection bias. That’s the situation faced by people studying the nature and prevalence of life in the universe. The only biosphere we know about is our own, and our knowing anything at all is predicated on its existence, so it’s unclear how much it can teach us about the bigger picture. That’s why it’s so important to search for life elsewhere. Today’s guest is Kevin Hand, a planetary scientist and astrobiologist who knows as much as anyone about the prospects for finding life right in our planetary backyard, on moons and planets in the Solar System. We talk about how life comes to be, and reasons why it might be lurking on Europa, Titan, or elsewhere.