domingo, 17 de fevereiro de 2008

Titan has "Hundreds of Times More" Liquid Hydrocarbons Than Earth

Written by Ian O'Neill
Titans landscape as seen by the Huygens probe decent through Saturns largest moons atmosphere (credit: ESA, NASA, JPL, UA, Rene Pascal)
According to new Cassini data, Saturns largest moon, Titan, has "hundreds" times more liquid hydrocarbons than all the liquid fossil fuel deposits on Earth. This is impressive as Titan's 5150 km diameter is only about 50% larger than Earth's Moon and only a little larger than the planet Mercury. Titan's hydrocarbons cycle into the atmosphere, fall as rain and collect in lakes creating massive lakes and dunes.

Titan is a planet-sized hydrocarbon factory. Instead of water, vast quantities of organic chemicals rain down on the moon's surface, pooling in huge reservoirs of liquid methane and ethane. Solid carbon-based molecules are also present in the dune region around the equator, dwarfing Earth's total coal supplies. Carl Sagan coined the term "tholins" to describe prebiotic chemicals, and the dunes of Titan are expected to be teeming with them. Tholins are essential for the beginning of carbon-based organisms, so these new observations by Cassini will stir massive amounts of excitement for planetary physicists and biologists alike.
The cold -179°C (-290°F) landscape of Titan is currently being mapped by the Cassini probe as it orbits the ringed gas giant, Saturn. Some 20% of the moons surface has been catalogued and so far several hundred hydrocarbon seas and lakes have been discovered. These lakes, individually, have enough methane/ethane energy to fuel the whole of the US for 300 years.
These new findings have been published in the January 29th issue of the Geophysical Research Letters by Ralph Lorenz from the Cassini radar team (Johns Hopkins University Applied Physics Laboratory, USA). Lorenz said on reviewing the Cassini data that, "we know that some lakes are more than 10 m or so deep because they appear literally pitch-black to the radar. If they were shallow we'd see the bottom, and we don't." He also steps into the life-beyond-Earth debate by pointing out: "We are carbon-based life, and understanding how far along the chain of complexity towards life that chemistry can go in an environment like Titan will be important in understanding the origins of life throughout the universe."
The ESA Huygens probe separated from Cassini and dropped slowly through the Titan atmosphere in January 2005 analyzing the atmospheric composition and taking some breathtaking images of the surrounding landscape. To complement the huge amount of data assembled from Huygens decent, Cassini will flyby the moon again on February 22nd to take radar data of the Huygens landing site.

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