Scientists studying the conditions on Saturn’s largest moon, Titan, have found that the particles covering much of its surface are electrically charged. Not only that, but the particles tend to clump together and become immovable dunes climbing to as high as 300 feet.
Science Daily reported this week that Titan, which has displayed a strange phenomenon where winds on the moon blow from east to west while massive 300-foot-tall sand dunes tend to form in the windward direction, is able to do so due to the electrification of the non-silicate granules that cover its surface.
Josh Méndez Harper, the lead author of the study and a Georgia Tech geophysics and electrical engineering doctoral candidate, said of the phenomenon, “These electrostatic forces increase frictional thresholds. 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.”
Professor Josef Dufek of Georgia Tech, a co-leader of the study, described the massive dunes.
“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 “Any spacecraft that lands in regions of granular material on Titan is going to have a tough time staying clean. Think of putting a cat in a box of packing peanuts.”
Researchers were challenged to approximate the conditions on Titan to test particle flow on the moon’s surface. To do so, they constructed a modified pressure vessel in their Georgia Tech laboratory. Granules of naphthalene and biphenyl — two toxic compounds believed to exist on Titan’s surface — were deposited into a small cylinder that was then rotated for 20 minutes in a dry, pure nitrogen environment, mirroring Titan’s own atmosphere, which is composed of 98 percent nitrogen. The electric properties of each inserted grain were subsequently measured as it fell out of the cylinder.
According to Mendez Harper, all the particles within the “tumbler” received an electrostatic charge, with roughly 2 to 5 percent remaining inside the tubular device. The team then performed an analogous experiment with particles that would be found on Earth and face Earth-like conditions.
“They clung to the inside and stuck together,” Mendez Harper noted. “When we did the same experiment with sand and volcanic ash using Earth-like conditions, all of it came out. Nothing stuck.”
It was found that particles on Earth actually do pick up an electrostatic charge. However, the charge is small and tends to fade rather quickly. This explains why water is necessary for sand cohesion on Earth. Titan, as the scientists discovered, is quite different with an environment where sand particles become cohesive and are nearly immovable for extended periods of time.
Co-author George McDonald, a graduate student in the School of Earth and Atmospheric Sciences, explained why this phenomenon occurs on Titan. “These non-silicate, granular materials can hold their electrostatic charges for days, weeks or months at a time under low-gravity conditions.”
Titan’s gravity is 0.14 that of Earth, just a bit weaker than that of our own moon.
Titan holds a special allure for scientists in that it appears to be very much like the Earth was, at least in theory, during its primordial development period. In 2010, NASA scientist Chris McKay announced that Titan was home to complex organic chemistry that could sustain life.
But Titan is also much different than Earth, as Space points out. Its dense atmosphere is composed of nearly nothing but nitrogen. However, enough elements exist to cause the formation of methane and ethane clouds. The weather patterns work similar to Earth’s, which has resulted in terrain features just like one would find on Earth, the exception being that instead of bodies of water one would find lakes, rivers, and streams of methane.
Dufek summed up the study’s findings, saying, “Titan’s extreme physical environment requires scientists to think differently about what we’ve learned of Earth’s granular dynamics. Landforms are influenced by forces that aren’t intuitive to us because those forces aren’t so important on Earth. Titan is a strange, electrostatically sticky world.”
[Featured Image by Vadim Sadovski/Shutterstock]