Sands in Saturn's Largest Moon Are Electrically Charged

A new study from Georgia Institute of Technology revealed that the sands in the surface of Saturn's largest moon Titan could be electrically charged.

The study, published in the journal Nature Geoscience, showed that the non-silicate granules of Titan become frictionally charged as they collide with each other in a process known as saltation. The sands could maintain charged for days or months and become more resistant to further motion caused by the winds.

"These electrostatic forces increase frictional thresholds," explained Josh Méndez Harper, a doctoral student in geophysics and electrical engineering at Georgia Tech and lead author of the study, in a press release. "This makes the grains so sticky and cohesive that only heavy winds can move them. The prevailing winds aren't strong enough to shape the dunes."

For the study, the researchers conducted a small experiment in modified pressure vessel to test how particles flow under Titan-like conditions. The researchers inserted grains of naphthalene and biphenyl into a small cylinder then rotated it in a dry, pure nitrogen environment for 20 minutes. Naphthalene and biphenyl are compounds that bear toxic, carbon and hydrogen and are believed to exist on Titan's surface. Titan is also thought to have an atmosphere that is composed of 98 percent nitrogen.

The researchers measured the electric properties of each grain as it tumbles out of the tube. They noted that all particles are charged well and about two to five percent of the grains clung to the inside of the tube and stuck together. When the researchers tried to conduct the same experiment using sands and volcanic ash in Earth-like conditions, they observed that nothing got stuck in the tube.

Compared to Earth sand that can only pick up charges for a brief period of time, non-silicate granular materials can hold their charges for days, weeks or months at a time under low-gravity conditions.

These findings could shed some light on a strange phenomenon that occurs on Titan. Astronomers have observed that the sandy dunes nearly 300 feet tall seem to form opposite to the prevailing winds that blow from east to west across Titan's surface.