Riddle dunes on Titan

Ten years ago, scientists were surprised to receive a "Cassini" strikingly beautiful photos with Titan - Saturn's largest moon. This is generally a wonderful cosmic body. Unlike other satellites, it dense atmosphere. There are rivers and lakes of the liquefied ethane and methane. But the most surprising - dunes hundreds of meters in height and length of tens of kilometers.

Scientists still can not tell from a bulk material made dunes and what is its source. And it is not clear how the dunes are formed of similar shape. This requires quite a strong wind, but "Cassini" this is not found. In addition, the shape of the dunes around obstacles such as mountains and craters indicates that the dunes formed west wind, but "Cassini" showed only a weak constant easterly wind on the satellite.



Puzzle dunes on Titan attempted to solve the researchers from the Department of Earth and Planetary Sciences at the University of Tennessee. The results of their scientific work опубликованы yesterday in the journal Nature.

Scientists headed by Associate Professor Burr Devon (Devon Burr) adapted for testing the old high-pressure wind tunnel NASA, which has long been out of order.



Six years (!) They spent on disaster recovery and reconstruction of the pipe atmospheric conditions on Titan.

Since the composition of sand on the surface is unknown, scientists have tested 23 different mixtures of bulk konstistentsii.

After two years of modeling and perenastroek install it turned out that the minimum strength of the wind, necessary for the formation of dunes, should be 50% larger than previously thought, according to the same computer models, designed for a more rarefied atmosphere.

In addition, it was found that the dunes are formed by short-term periods of strong west wind. According to the atmospheric models, the constant weak easterly wind on Titan may be replaced by short intervals of strong westerly winds. It happens once a year on Titan (one year or about 30 Earth years), when the sun crosses the equator. Because of the rarity of the phenomenon of "Cassini" could miss it.

via phys.org i>

Source: geektimes.ru/post/242683/