Thursday, January 07, 2010

Researchers find similarities between Earth and Saturn's largest moon

Researchers using ground-based telescopes and space probes make amazing discoveries about the atmospheric cycle of Saturn’s largest moon, and find similarities to Earth. Our knowledge of Titan has improved considerably over the last five years. Before that, Saturn's largest satellite had only been hastily approached by a handful of space probes.

In 1980, the Voyager-1 spacecraft took advantage of a flyby to take a few mysterious, yet frustrating, close-ups of Titan's opaque, rusty atmosphere. Despite its color, Titan actually seemed to look a lot like the early Earth.

There was a general feeling of excitement and perplexity: what lay beneath this atmosphere? Could Titan support life? In July 2004, NASA's Cassini space probe entered Saturn's distant realm, this time to stay. The probe was designed right after Voyager's visit by a scientific community eager to unveil those new mysteries.

And unveil them it did. It has been hard to keep up with the flow of discoveries delivered from Titan to Earth since then. We now know that the 5,150-kilometer- (km, or 3,200-mile-) wide world has lakes and riverbeds. Earlier this year, even fog was discovered at Titan's South Pole.
Even more compelling is the fact that, just like similar features on Earth, all of those features are tightly related. Evaporated liquids create clouds that are carried around the planet by winds--and probably cause precipitation. This has never been seen on any other extraterrestrial body.

Moreover, Titan's atmospheric cycle is not a water cycle. It is instead an exotic climate of hydrocarbons that features methane and ethane. On Earth, those are gases, but the extremely cold temperature of Titan, around minus 290 degrees Fahrenheit (F, or minus 180 degrees Celcius), allows them to be liquid as well (and maybe even solid).


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