BBC Earth (Asia) - - Update -

If you want to make the best sand­cas­tle in the So­lar Sys­tem, you might want to head to Ti­tan. Re­searchers at the Ge­or­gia In­sti­tute of Tech­nol­ogy have dis­cov­ered that grains of sand on the sur­face of Saturn’s largest moon can be­come elec­tri­cally charged, mak­ing them stick to­gether more eas­ily.

When wind blows across the moon’s sur­face at 25km/h or more, the gran­ules swirl into the air and start to col­lide. As this hap­pens they be­come charged, like a bal­loon rub­bing against your hair, and stick to­gether. “If you grabbed piles of grains and built a sand­cas­tle on Ti­tan, it would per­haps stay to­gether for weeks due to their elec­tro­static prop­er­ties,” said re­searcher Dr Josef Dufek.

The ef­fect could help to ex­plain the sandy dunes seen on Ti­tan’s sur­face that can reach heights of 100m, the re­searchers say.

To make the dis­cov­ery, the team placed grains of naph­tha­lene and biphenyl – two toxic, car­bon- and hy­dro­gen-bear­ing com­pounds be­lieved to ex­ist on Ti­tan’s sur­face – into a ro­tat­ing ni­tro­gen-filled cylin­der for 20 min­utes.

“All of the par­ti­cles charged well, and about

2 to 5 per cent didn’t come out of the tum­bler,” ex­plained re­searcher Mén­dez Harper. “They clung to the in­side and stuck to­gether. When we did the same ex­per­i­ment with sand and volcanic ash us­ing Earth-like con­di­tions, all of it came out. Noth­ing stuck.”

Earth sand does pick up static elec­tri­cal charge when it’s moved, but the charges are small and dis­si­pate quickly – this is why you need water to keep the sand to­gether when you are build­ing a sand­cas­tle at the sea­side.

Ti­tan, as seen by the Cassini space­craft

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