Today on Discovery Enterprise we present the second instalment of the acclaimed documentary series narrated by Christopher Plummer.
Episode 2 of Miracle Planet takes us back more than two billion years, to this first ice age that gripped the Earth for what scientists believe was millions of years. Snowball Earth reveals the startling secrets of how life survived this devastating cold and how this extreme climate shift forever changed the development of life on Earth.
Snowball Earth refers to the highly contested hypothesis that the Earth’s surface became nearly or entirely frozen over at least once during three periods between 650 and 750 million years ago. The geological community generally accepts this hypothesis because it best explains sedimentary deposits generally regarded as of glacial origin at tropical paleolatitudes and other enigmatic features in the geological record. Opponents to the hypothesis contest the implications of the geological evidence for global glaciation, the geophysical feasibility of an ice- or slush-covered ocean, and the difficulty of escaping an all-frozen condition. There are a number of unanswered questions, including whether the Earth was a full snowball, or whether it was a “slushball” with a thin equatorial band of open (or seasonally open) water. The geological time-frame under consideration comes immediately before the sudden multiplication of life-forms on earth known as the Cambrian explosion and may have triggered multi-cellular life on earth.
But, recent evidence has dealt this hypothesis a serious blow by new evidence that periods of warmth occurred during this so-called ‘Snowball Earth’ era.
Miracle Planet – Episode 2: Snowball Earth