Using NASA's Cassini spacecraft researchers determined sand dunes on Saturn's moon Titan were created by super-strong winds.
A research team determined winds on Titan would have to blow 50 percent faster than previously thought in order to move the giant sand dunes, Johns Hopkins University of Applied Physics Laboratory reported.
"It was surprising that Titan had particles the size of grains of sand - we still don't understand their source - and that it had winds strong enough to move them," said Devon Burr, an associate professor in the Earth and Planetary Sciences Department at the University of Tennessee, Knoxville, and lead author of the paper. "Before seeing the images, we thought that the winds were likely too light to accomplish this movement."
The most mysterious aspect of the dunes was their shape; the findings suggested they were formed by winds that blew from east to west even though they appear as if they were formed from the opposite direction.
"Until now, there's been a big mystery as to why most winds on Titan blow from the east, yet the dunes appear to form from westerly winds," said Nathan Bridges, planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and a co-author of the paper.
To make their findings the researchers used a pressurized wind tunnel that simulated the physics on Titan using 24 different substances such as low-weight particles and walnut shells.
"Our models started with previous wind speed models, but we had to keep tweaking them to match the wind tunnel data," Burr said. "We discovered that movement of sand on Titan's surface needed a wind speed that was higher than what previous models suggested."
According to the models the wind on the moon reverses twice every Saturn year (equal to about 30 Earth years) and creates the dunes when it blows from east to west.
The findings were published in a recent edition of the journal Nature.