00463nam a2200085Ia 4500008004100000245001900041300025300060650001300313856005100326170517s9999    xx            000 0 und d  aSnowball Earth  aOver 650 million years ago, our entire planet existed in a frozen state. So speculates the hypothesis known as Snowball Earth. The mounting evidence of this controversial phenomenon is explored in great depth in the second episode of Catastrophe...  xScience.  uhttp://topdocumentaryfilms.com/snowball-earth/