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Sand Dunes on Saturn Moon

Saturn’s moon Titan has huge regions covered with dunes, possibly made out of ice crystals, sand or some other unknown material, international space scientists reported on Thursday.

Images of Titan beamed back to Earth from the joint U.S.-European Cassini mission look very much like sand dunes in the Sahara desert, Namibia, Saudi Arabia and Australia, the researchers said. The latest radar images show the dunes are up to 500 feet (150 meters) high and hundreds of miles (kilometers) long. Dark patches on Titan, the largest of Saturn’s 47 moons, were at first thought to be seas — but now they appear to be largely made up of these dunes.

On Earth, sand dunes are created by wind and wind is a result of heat differences produced by sunlight that warms the planet unevenly. Scientists have long assumed Titan is too far from the Sun to have solar-driven surface winds powerful enough to cause sand dunes.

Titan’s flat surface is very cold, with a temperature of minus 180 degrees Celsius and scientists believe its thick atmosphere may occasionally rain methane.

Scientists have more recently learned that Saturn’s powerful gravity creates tidal effects in Titan’s thick atmosphere. This tidal force, almost 400 times greater than that of Earth’s moon tugging at our oceans, dominates near surface winds on Titan and sculpts dunes that are up to 330 feet high.

The existence of pristine dunes, piled over other geological features, shows that wind recently blew fine grains of some material around, the researchers wrote in their report, published in the journal Science. It could be sand, ice or something else, they added.

posted by: kyawoo at 21:23 | link | comments |
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