As the seasons change on Mars, the activation of the wind, the dunes if they move slowly.
Martian dunes blowing in the wind, but slowly, and on the basis of factors that do not impact on sand movement here on Earth.
Scientists followed the movement of nearly 500 individual dunes, all with the help of data collected by NASA’s Mars Reconnaissance Orbiter. By studying the movements of all that sand, the researchers were able to compare the interaction between the wind and the sand on the Red Planet with the same interaction on Earth.
“On Mars, there is simply not enough wind energy to a significant amount of material around on the surface,” lead author Matthew Chojnacki, a planetary scientist at the University of Arizona, said in a statement. “It takes two years on Mars to see the same movement you would generally in a season on Earth.”
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Chojnacki and his colleagues used images taken by HiRISE, a special camera aboard the Mars Reconnaissance Orbiter, the images of the surface of Mars with incredibly detailed photos. Those photos are plenty of scenes of dunes rippling across the planet.
Scientists are especially interested in the dunes, because they are areas where the surface is changing enough that the same material does not constantly bombarded by the harsh environment. “If you don’t sand move, which means that the surface is just sit down, get bombarded by uv and gamma radiation that would destroy complex molecules and all the past Martian biosignatures,” Chojnacki said.
By selecting pairs of images from the same patch of ground year, the team was able to measure how quickly each dune is moving. That analysis suggests that Martian dunes move at a fraction of the speed of those found on Earth — which makes sense, considering how much thinner the atmosphere of the Red Planet than the Earth.
What was less predictable was that only a handful of places would make the sport significantly more sand movement: were driven Major, the Hellespontus mountains and a region called the north polar ergs. The researchers think that the relatively rapid sand movement here may be caused by dramatic changes in the surface height, and temperature that arise where different types of surface properties neighbour each other. That is not a situation that requires wind here on Earth.
“Those are not the factors that you would find in terrestrial geology,” Chojnacki said. “On Earth, the factors at work are different on Mars. For example, the groundwater close to the surface or plants in the area retard dune sand movement.”
The research is described in a paper published on 11 March in the journal Geology.
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Original story on Space.com.