Tracing the history and evolutionary implications of a controversial theory, which posits that for millions of years the Earth was entirely covered in ice up to a kilometre thick.
There is a controversial theory that for millions of years the Earth was plunged into a catastrophe and entirely smothered in ice, up to one kilometre thick. The temperature hovered around minus 40 C - everywhere, even in the tropics and the equator. If this really happened, then virtually nothing could have survived this ferocious climate. There are some tantalising geological clues that show this theory may be true but the problem is, the clues and the Snowball Earth theory defy the laws of nature.For over fifty years a group of scientists have been trying to prove this incredible period of Earth history. Struggling against scepticism and disbelief, now finally the many mysteries have been solved and the scientific community is slowly coming around to the extraordinary idea not just of the dramatic freeze, but of an equally dramatic thaw.From the baking landscape of Africa to ice-covered Antarctica, Horizon follows the tale of a theory which, if true, would have huge implications. Because scientists now believe this cycle of freezing and frying may have created the unique conditions needed for the evolution of complex life, including our own - and that humans only exist because of the catastrophic events of Snowball Earth.
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Clips
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Evolutionary explosion
Duration: 01:27
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Snowball Earth theory
Duration: 05:01
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The return of Snowball Earth?
Duration: 02:43
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The end of Snowball Earth
Duration: 03:33
Broadcasts
- Thu 22 Feb 2001 21:00ÃÛÑ¿´«Ã½ Two except East, South East & Yorkshire
Wed 7 Mar 2001 10:00ÃÛÑ¿´«Ã½ Knowledge
Wed 7 Mar 2001 13:00ÃÛÑ¿´«Ã½ Knowledge
Wed 7 Mar 2001 16:00ÃÛÑ¿´«Ã½ Knowledge
Wed 7 Mar 2001 19:00ÃÛÑ¿´«Ã½ Knowledge
Wed 7 Mar 2001 22:00ÃÛÑ¿´«Ã½ Knowledge
Thu 8 Mar 2001 01:00ÃÛÑ¿´«Ã½ Knowledge
Sun 11 Mar 2001 07:00ÃÛÑ¿´«Ã½ Knowledge
Sun 11 Mar 2001 11:00ÃÛÑ¿´«Ã½ Knowledge
Sun 11 Mar 2001 15:00ÃÛÑ¿´«Ã½ Knowledge
Sun 11 Mar 2001 19:00ÃÛÑ¿´«Ã½ Knowledge
Sun 11 Mar 2001 23:00ÃÛÑ¿´«Ã½ Knowledge
Sun 17 Jun 2001 09:30ÃÛÑ¿´«Ã½ Knowledge
Sun 17 Jun 2001 12:30ÃÛÑ¿´«Ã½ Knowledge
Sun 17 Jun 2001 15:30ÃÛÑ¿´«Ã½ Knowledge
Mon 18 Jun 2001 00:00ÃÛÑ¿´«Ã½ Knowledge
Sun 28 Oct 2001 10:00ÃÛÑ¿´«Ã½ Knowledge
Sun 28 Oct 2001 13:10ÃÛÑ¿´«Ã½ Knowledge
Sun 28 Oct 2001 16:00ÃÛÑ¿´«Ã½ Knowledge
Sun 28 Oct 2001 19:00ÃÛÑ¿´«Ã½ Knowledge
Mon 29 Oct 2001 00:10ÃÛÑ¿´«Ã½ Knowledge- Wed 17 May 2006 10:40ÃÛÑ¿´«Ã½ Two except East, South East & Yorkshire