The study describing this finding, co-authored by UT researcher Devon Burr, was published this week in the journal Nature Geoscience.
Researchers at the Georgia Institute of Technology led the experiments for the study.
When the wind blows hard enough, Titan’s nonsilicate granules get kicked up and start to hop in a motion referred to as saltation. As they collide, they become frictionally charged—like a balloon rubbing against your hair—and clump together in a way not observed for sand dune grains on Earth. They become resistant to further motion. They maintain that charge for days or months at a time and attach to other hydrocarbon substances, much like packing peanuts used in shipping boxes here on Earth.
The electrification findings may help explain an odd phenomenon. Prevailing winds on Titan blow from east to west across the moon’s surface, but sandy dunes nearly 300 feet tall seem to form in the opposite direction. It seems the electrostatic forces increase the frictional quality of the grains and make them stickier. Stickier grains would not respond to the prevailing east-to-west winds but only to the very strongest winds, which blow in the opposite direction.
To test particle flow under Titan-like conditions, the Georgia Tech researchers built a small experiment in a modified pressure vessel in their lab.
Burr, associate professor of earth and planetary sciences, provided some of the research that was crucial to the study, including information about previous experimental work on wind tunnels. She was the lead author on the first experimental work that tested the assumptions that had been made in applying Earth-based wind sedimentation models to Titan. This previous work suggested that winds have to blow stronger than expected to form dunes on Titan. The new work on electrification expands on this previous suggestion.
This study also includes work from researchers at the Jet Propulsion Lab and Cornell University.