Titan is in orbit around Saturn, and so the moons seasons are controlled by Saturns path around the sun. Because Saturn takes about 30 years to complete an orbit, each season on Titan lasts for about seven years. The slightly elliptical nature of Saturns orbit means that the southern hemisphere of Titan has shorter but more intense summers. So the southern regions are probably drier, which implies they have less ground moisture. The drier the sand grains, the more easily they can be transported by the winds to make dunes. As one goes to the north, we believe the soil moisture probably increases, the sand particles less mobile and, as a consequence, the development of dunes more difficult. says Le Gall.
Backing this hypothesis is the ct that Titans lakes and seas are not distributed symmetrically by latitude. These reserves oCassini Sees the Two Faces of Titans Dunes development of radarf liquid ethane and methane are predominantly found in the northern hemisphere, suggesting again that the soil is moister toward the north and so, again, the sand grains are less easy to transport by the wind.
For more information about the Cassini mission, visit:
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASAs Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASAs Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries.
Though similar in shape to the linear dunes found on Earth in Namibia or the Arabian Peninsula, Titans dunes are gigantic by our standards. They are on average 0.6 to 1.2 miles (1 to 2 kilometers) wide, hundreds of miles (kilometers) long and around 300 feet (100 meters) high. However, their size and spacing vary across the suce, betraying the environment in which they have formed and evolved.
Using radar data from the Cassini spacecraft, Alice Le Gall, a former postdoctoral fellow at NASAs Jet Propulsion Laboratory, Pasadena, Calif., who is currently at the French research laboratory LATMOS, Paris, and collaborators have discovered that the size of Titans dunes is controlled by at least two ctors: altitude and latitude.
2012-021
In terms of latitude, the sand dunes on Titan are confined to its equatorial region, in a band between 30 degrees south latitude and 30 degrees north latitude. However, the dunes tend to be less voluminous toward the north. Le Gall and colleagues think that this may be due to Saturns elliptical orbit.
In terms of altitude, the more elevated dunes tend to be thinner and more widely separated. The gaps between the dunes seem to appear to Cassinis radar, indicating a thinner covering of sand. This suggests that the sand needed to build the dunes is mostly found in the lowlands of Titan.
Markus Bauer 011-31-71-565-6799
__JPL_CAPTION_1
Understanding how the dunes form as well as explaining their shape, size and distribution on Titans suce is of great importance to understanding Titans climate and geology because the dunes are a significant atmosphere-suce exchange intece, says Nicolas Altobelli, ESAs Cassini-Huygens project scientist. In particuladevelopment of radarr, as their material is made out of frozen atmospheric hydrocarbon, the dunes might provide us with important clues on the still puzzling methane/ethane cycle on Titan, comparable in many aspects with the water cycle on Earth.
› Browse version of image
Scientists think the sand on Titan is not made of silicates as on Earth, but of solid hydrocarbons, precipitated out of the atmosphere. These have then aggregated into grains 0.04 inch in size by a still unknown process.
Jet Propulsion Laboratory, Pasadena, Calif.
European Space Agency, Noordwijk, the Netherlands
Cassini Sees the Two Faces of Titans Dunes development of radar,Dune fields are the second most dominant landform on Titan, after the seemingly uniform plains, so they offer a large-scale insight into the moons peculiar environment. The dunes cover about 13 percent of the suce, stretching over an area of 4 million square miles (10 million square kilometers). For Earthly comparison, thats about the suce area of the United States.
Jia-Rui Cook 818-354-0850
-->A new analysis of radar data from NASAs Cassini mission, in partnership with the European Space Agency and the Italian Space Agency, has revealed regional variations among sand dunes on Saturns moon Titan. The result gives new clues about the moons climatic and geological history.
