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Titan's secrets revealed

Thanks to the Cassini spacecraft and the Huygens probe, scientists are unearthing the secrets of Satuirn's mysterious moon — Titan. NASA’s Cassini first flew past Titan in October last year, providing close-up radar images of the moon’s cloud- shrouded surface. On January 14 the European Space Agency’s Huygens probe (which was deployed from the Cassini oribiter) landed successfully on Titan.

Scientists realized that Titan is a very complex place, really a planet in its own right that happens to be in orbit around another planet.

The nitrogen and methane in Titan’s atmosphere combine into long chains of hydrocarbons. For nearly two decades scientists had theorized that these hydrocarbons would condense and rain onto Titan’s surface, perhaps creating methane lakes or liquid- filled craters. Cassini has altered such theories. Liquid lakes are not seen on Titan. Scientists are now thinking that regions of liquid will be fairly confined if they find them at all. A new hypothesis likens Titan’s rain cycle to that of a frigid Arizona, where occasional methane precipitation carves riverbeds that are dry during most of the year.

On Titan, processes seen on Earth, like windswept surfaces and streams carved by liquid, are present but are played out with different materials.

Researchers expected the moon to be dotted with craters, but only two have been spotted so far, indicating that there are active geological processes which are erasing surface features.

Volcanism is one such process that may well be at work. But on frigid Titan it involves not lava but water-ice-based "cryolava." If you add something like ammonia to water you get a much colder melting point, a molasses-like texture, and a more buoyant liquid that will periodically come out [of cracks or other fissures in the icy surface]. These "cryovolcanic" processes may be at working shaping and reshaping Titan’s surface, in much the same way that hot volcanic activity does on Earth.

Specific atmospheric traits are also emerging from the Cassini data. Titan’s winter polar atmosphere may have interesting parallels with Earth’s Antarctic ozone hole—albeit with different chemistry.

Infrared images reveal frigid temperatures (-290 degrees Fahrenheit, -180 degrees Celsius) circumpolar winds up to 358 miles per hour (576 kilometers per hour), and polar concentrations of atmospheric organic compounds that are different from those of other latitudes.

posted by: kyawoo at 10:32 | link | comments |
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