Glaciers May Have Covered the Entire Planet–Twice

Drawing on evidence across multiple continents, scientists say these Snowball Earth events may have paved the way for the Cambrian explosion of life that followed—the period when complex, multicellular organisms began to diversify and spread across the planet. When Caltech geologist Joe Kirschvink coined the term Snowball Earth in 1989—merging ideas that some geologists, climate physicists and planetary chemists had been thinking about for decades—many earth scientists were skeptical that these cataclysmic events could really have occurred. The biggest problem was that because the conditions were so different from any other time in Earth’s history, we didn’t understand the implications of the hypothesis well enough to know whether any given bit of geologic evidence was either for or against it.

Source: nautil.us