REAL LIFE NEWS: THE BACKWARDS DUNES OF TITAN
by Hazed
Titan’s equatorial regions are covered with dunes, up to 100 metres high. But these piles of shifting sands face the wrong way – Titan’s prevailing winds blow towards the west, but the dunes point east. Now scientists have come up with a theory that could explain this paradox.
Josek Dufek from the Georgia Institute of Technology in Atlanta wanted to figure out why Titan’s sand dunes were back to front, so he and his colleagues experimented with grains of organic material similar to those found on the moon’s surface, placing them in a cylindrical chamber with conditions that simulated Titan’s winds.
When the scientists opened the chamber, the grains were all clumped together. The cause was static electricity created by the grains jostling in the dry air of the chamber.
“It was like when you open a box on a winter morning and the packing peanuts stick everywhere,” says Dufek. “These hydrocarbons on Titan are low density and they stick to everything, just like packing peanuts do.”
On Titan, the grains can maintain that charge for much longer than on Earth because of their low density and the dryness of the moon’s atmosphere. This means they stick together for a lot longer. The breeze close to Titan’s surface generally stays below 5 km per hour, which isn’t enough to shift the dunes.
More powerful winds, caused by seasonal changes or storms, then blow the dunes eastwards, forming the dunes that appear to go against the prevailing winds. That’s what the scientists think is happening, anyway, but we’ll probably not be able to confirm this without sending another probe to Titan.
