The dunes of Saturn's largest moon, Titan, may be held together by static electricity.

Grains of sand acquire electrostatic charge as they rub against each other, but on Earth this effect is generally negligible because gravity and a high density of heavy silicate particles minimize interactions between the particles. Joshua Méndez Harper at the Georgia Institute of Technology in Atlanta and his colleagues recreated conditions on Titan, which has one-seventh the gravity of Earth and hydrocarbon-based sand. In their lab experiments, the researchers showed that these lighter grains generated electrostatic forces strong enough to clump some of the grains together.

This could explain why sand dunes at Titan's equator seem to grow into the wind.

Nature Geosci. http://dx.doi.org/10.1038/ngeo2921 (2017)