Saturn's moon Titan is one of the most Earth-like places in the solar system, and new research suggests it experiences violent methane storms.
The Cassini-Huygens spacecraft spotted seemingly wind-created dunes pointing to the east on the moon's surface, but this was puzzling because Titan is believed to only have near-surface winds that blow westward, the University of Washington reported. Using computer models, a team of researchers determined the mysterious dunes could be created by rare methane storms that produce strong eastward gusts of wind.
"These fast eastward gusts dominate the sand transport, and thus dunes propagate eastward," said University of Washington astronomer Benjamin Charnay, co-author of the paper published today in the journal Nature Geoscience.
These storm winds are believed to reach about 22 miles per hour, which is a whopping 10 times faster than Titan's near-surface winds. The storms most likely only occur when Titan is in equinox, which occurs every 14.75 years. Titan's atmosphere is composed of 98.4 percent nitrogen, and the rest is methane and hydrogen. In the first climate model looked at by the researchers, methane was not factored in. The simulations showed that the creation of the dunes was impossible, suggesting methane played a key role in the appearance of the features.
"It was a kind of detective game, as often is the case in planetary sciences, where we have many mysteries and a few clues to solve them," Charnay said.
More direct observations from Cassini could help confirm the existence of these methane storms, but the mission ends in 2017 and the next Titan equinox will not occur until 2023.
"But there will be other missions. There are still a lot of mysteries about Titan. We still don't know how a thick nitrogen atmosphere formed, where the methane comes from nor how Titan's sand forms," Charnay said. "And it is not completely excluded that life can be there, perhaps in its methane seas or lakes. So Titan really is a fascinating and evolving world, which has to be understood as a whole."