Saturday, November 07, 2009
"Underwater Universe" on History Channel: more about tsunamis and underwater volcanoes and earthquakes, as well as "The Deep"
On Monday Nov. 3 The History Channel aired its documentary “Underwater Universe”, about the “Seven Deadly Underwater Seas”. The DVD link is here.
The film covered most of the well-known catastrophes, including underwater earthquakes and volcanoes, tsunamis (including the 2004 Indonesian tsunami), hurricanes, whirlpools (as off the coast of Maine), and icebergs (including the sinking of Titanic). Tsunamis whip up a lot of sand as well as water, adding to destructive potential.
A interesting segment involved Santorini, which exploded as an underwater volcano in ancient times and wiped out much of Minoan civilization. It was the second largest volcanic explosion in history, resulting in 200 foot tsunami waves. Underwater volcanic explosions can release sulfuric acid rain and smother small areas with carbon dioxide, as can small volcanoes on land (resulting in deaths by smothering; this has happened).
The iceberg segment was interesting, in that it explained how icebergs get harder and less dense as the temperature gets colder because of the unusual bonding angles between the atoms in the water molecule.
There was also a segment explaining the exploration down below 30000 feet with the submersible, the Trieste, in the Challenger Deep Trench in the Pacific. The film discussed zones in the deep ocean called Abyssalpelagic and Bathypelagic (try this SVG on Wikipedia).
The end of the film mentioned man’s effect on the oceans as making them more unstable, especially with melting of ice caps.
The Earth is the densest planet in the Solar System, even with its liquid ocean, according to a question on Jeopardy. The only other body known to be likely to have a large water ocean (underneath ice) is Europa, although that may be possible with Titan also (Titan has methane or ethane oceansor lakes on its surface).
Wikiepedia NOSA ocean gravity map.