Sunday, 5 June 2011

Earth Story

I recently watched Earth Story, an 8 part 6.5 hour long T.V series produced by the BBC, narrated by Aubrey Manning, and released in 1998, detailing the history of the Earth, beginning with measuring the Earth's age by observing geological change and using radioactive temperature as an indicator, in part 1 - 'The Time Travellers', to finding evidence for why our planet is so unique in part 8 - 'A World Apart', like it's ability to regulate CO2 emissions in the carbon cycle, using water as a lubricant in tectonic shift, etc.

The series presents various discoveries that helped us in our understanding of the Earth's history, like how sonar, explosives and satellites helped uncover a continuous mountain ridge running on the surface of the oceans, magnetic in nature, pointing towards the existence of Pangaea and continental drift (Part 2 - The Deep). Part 3 - 'Ring of Fire' continues with the same theme, explaining the existence of tectonic plates and exploring how and why shifting plates create new earth, and the role volcanoes play. 

Part 4 - 'Journey to the Centre of the Earth' looks at some of the causes behind tectonic movement, demonstrating how convecting land plumes formed by heat from the earth's molten core moves land plates up, only to have them sink again when cool, moving under other plates, causing earthquakes and volcanoes, through which heat from sinking land escapes. 

Part 5 - 'The Roof of the World' focuses on India and Tibet, noting that mountain ranges are caused by land masses moving against each other, like the Himalayas being formed when India merged with Asia, where the pressure even created granite rock. It's also revealed that Tibet is sinking fast, which is probably just a consequence of it rising so fast in the past after it lost it's land plume anchor (the land version of an iceberg), and is now settling and spreading out. 

Part 6 - 'The Big Freeze' looks at the reasons behind periodic ice ages and constant climate change; part 7 - 'The Living Earth' looks at early life in the oceans, 500 million yrs ago, and the creation of oxygen.

What struck me while watching the series was how everything we know about the history of the Earth is really a cumulative effort. No one man or woman has been responsible for recent scientific progress in this area. It has been a collective effort between geologists, meteorologists, biologists, botanists, engineers, chemists, technicians and all kinds of scientists involved in climate, mapping, radio isotoping, carbon dating, etc.


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