Excerpt from space.com
The towering dunes on Saturn’s largest moon, Titan, may look similar to the sandy hills of Earth’s Sahara, but their origins are completely different, researchers say. Instead of forming continuously over time like on Earth, Titans dunes are forged by short, powerful rogue winds.
Reaching heights of more than 300 feet (91 meters), the dunes of Titan present a puzzling mystery: they seem to form in the opposite direction as Titan’s steady east-to-west winds. Two new studies suggest that rare bursts of wind blowing westward are responsible for these enormous structures. The findings shed light on the remote satellite that shares many qualities with Earth.
“It was a bear to operate, but Dr. Burr’s refurbishment of the facility as a Titan simulator has tamed the beast. It is now an important addition to NASA’s arsenal of planetary simulation facilities,” John Marshall, of the SETI Institute, and a co-author on the new research, said in the statement.
Titan’s dunes are not made of the kind of sand found in deserts on Earth, but a more viscous material. Scientists don’t know exactly what it is, only that it is made of hydrogen and carbon — two ingredients that can be used to create a laundry list of different materials on Earth, from methane to paraffin wax. According to Burr, the hydrogen-carbon material may coat particles of water ice.
The researchers found that the regular east-to-west winds are not strong enough to shape the viscous material into the massive dune shapes that are observed. Instead, they believe the dunes are shaped by short, rapid bursts of westerly wind. The winds on Titan “occasionally reverse direction and dramatically increase in intensity due to the changing position of the Sun in its sky,” the statement said.