An Earth covered in ice might sound far-fetched, but there’s reason to think it has actually happened in the past – more than once. In this episode, we examine the Snowball Earth hypothesis and the geologic evidence and climate models that back it up, as well as some of the major lingering questions: Just how snowy is the snowball? How could this start? How could it end? And how did life fare on a frozen planet?

In the news: ancient tardigrades, meat-eating sloths, shark communities, and relict mangroves.

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The Intro and Outro music is “On the Origin of Species” by Protodome.

Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0