There's Sand on Titan, Where Does it Come From?

"The motivation behind the study is to try to answer the third mystery. If the dune materials are processed through liquids, which are located in the polar regions of Titan, they need to be strong enough to be transported from the poles to the equatorial regions of Titan, where most of the dunes are located. However, the tholins we produced in the lab are in extremely low amounts: the thickness of the tholin film we produced is only around 1 micron, about 1/10-1/100 of the thickness of human hair. To deal with this, we used a very intriguing and precise nanoscale technique called nanoindentation to perform the measurements. Even though the produced indents and cracks are all in nanometer scales, we can still precisely determine mechanical properties like Young’s modulus (indicator of stiffness), nanoindentation hardness (hardness), and fracture toughness (indicator of brittleness) of the thin film."