Snowball Earth - Over 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 series, as scientists and geologist comb the farthest reaches of the globe in search of the next clue of Earth's rich and elusive history.
Artist's concept of a Snowball Earth. During vast ice ages millions of years ago, sheets of glaciers stretched from the poles almost to the equator, covering the Earth in a frozen skin. Conditions on the "snowball Earth," as scientists refer to it, made the planet a completely different place. "We're essentially talking about another world," said Linda Sohl of the NASA Goddard Institute for Space Studies in New York.