Even though not all of them leave visible traces

Dec 18, 2009 18:11 GMT  ·  By

In a groundbreaking finding that could explain another one of the Red Planet's atmospheric mysteries, experts have determined that the frequency of twisters and dust devils forming on the surface of Mars is about 300 percent higher than first predicted. This could account for the massive plumes of dust that remain airborne for prolonged periods of time, for no apparent reason. The team behind the new investigations has determined that a lot more events such as these ones take place on our neighboring planet than on our own, ScienceNow reports.

One of the main reasons for this is the fact that light and heat coming in from the Sun hit the low-lying layers of air on Mars, and then heat them up. Once the temperatures exceed a certain threshold, the air starts rising into the cooler layers above. This is the same effect that can be met back on Earth, where the warmer air will also be found near the ceiling of a room, whereas the cold one will always be at the bottom. The devils and twisters occur as these layers switch places, experts say.

The intensity with which the dust devils and the twisters occur could imply that they are a very important component of the Martian atmosphere, dictating the planet's climate and overall temperatures, the experts say. Previous counts for these structures had been taken from satellites around the planet, which photographed the tracks they left behind. But new images, taken by one of the MER rovers on the surface of the planet, proved the count to be terribly under-estimative of the actual number.

“We found roughly one in 300 dust devils leaves a track in the Gusev crater. It was a big surprise. Now we know tracks are the exception rather than the rule. Further exploration will tell us how applicable this is to the rest of the planet,” US Geological Survey (USGS) research geologist Paul Geissler says. He is a member of the study team that presented the new findings on Tuesday, at the annual meeting of the American Geophysical Union (AGU), in San Francisco. The new numbers were obtained after comparing data from the Mars Reconnaissance Orbiter (MRO) with a video relayed back by the NASA rover Spirit, currently stuck at the Gusev crater, near the Home Plate.

“This study is very important because [dust devils] are a big source of dust in the atmosphere on Mars. Who knows if we're getting [our models] right, if we're not getting the dust cycle right? There's a lot to unravel, and this is a good step in the right direction,” NASA Ames Research Center Planetary Systems Branch Martian climate modeler Jeffery Hollingsworth says.