Titan, Saturn’s largest moon. Image: NASA/JPL/University of Arizona/University of Idaho
By Jason Maderer
New experiments suggest the particles that cover the surface of Saturn’s largest moon, Titan, are electrically charged. When the wind blows hard enough, Titan’s non-silicate 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 hair. They clump together in a way not observed in sand grains on Earth.
“If you grabbed piles of grains and built a sand castle on Titan, it would perhaps stay together for weeks due to their electrostatic properties,” said Josef Dufek, the Georgia Tech School of Earth and Atmospheric Sciences professor who co-led the study. “These charged grains will stick to each other and other surfaces. Think of putting a cat into a box of packing peanuts.”
The electrification findings may help explain an odd phenomenon. Prevailing winds on Titan blow from east to west across the moon’s surface, but sand dunes nearly 300 feet tall seem to form in the opposite direction.
“These electrostatic forces increase frictional thresholds,” said Josh Méndez Harper, a Georgia Tech doctoral student. “This makes the grains so sticky and cohesive that only heavy winds can move them.
The researchers modified a pressure vessel to test the charging of particles like those on Titan. The research was supported by the National Science Foundation and reported in the journal Nature Geoscience.