Across the far northern regions of Mars, a sea of dunes dots the red landscape, continuing on for thousands of miles. At first glance they appear like fossils of geography—reminders of a time when Mars was vivacious and windswept that now find themselves encrusted and stationary.
Looks can be deceiving. A research team confirms in Science this week that Mars’ dunes are not static. Atmospheric processes forged by the turning of Mars‘ seasons cut into the dunes and send sand flying about. Scientists just couldn’t see it before.
“I was hoping for tiny little changes to be detectable,” planetary scientist Candice Hansen-Koharcheck with the Planetary Science Institute in Tucson, Ariz., [said]. “This was more like knock-your-socks-off kind of stuff. It’s a very active part of the Mars landscape in today’s climate.” [Discovery News]
Hansen-Koharcheck turned the HiRISE camera of the NASA Mars Reconnaissance Orbiter on the dunes, and recorded for two Martian years (four Earth years or so). Earlier HiRISE pictures suggested that the dunes were not unchanging. These new images show not only that the dunes of Mars are a dynamic place, but, according to the team, that the forces pushing their evolution are not seen on our planet.
The Martian rovers and orbiters have sent so much data back to Earth in the last few years that discoveries about Mars’ wet and active past come left and right. Yesterday we covered the story that the stuck Spirit rover may have found evidence of recent water right under its tracks. And another study this week, out in Nature Geoscience, pinpoints a spot by a Mars volcano that could contain evidence of a watery system more than 3 billion years old—and perhaps even life, too.
The finding came after the Mars Reconnaissance Orbiter observed a mineral called hydrated silica sitting on the flank of the extinct Syrtis Major volcano.
The mineral is transported and then concentrated by hot water or steam, suggesting the deposits were laid down in what was once a hydrothermal environment. Groundwater may have been heated by magma from the erupting volcano and vented to the surface as steam, says John Mustard of Brown University in Rhode Island, a member of the team that identified the mineral. [New Scientist]
That’s not cloud cover. It’s polar ice on Mars, about 600 miles across and covered with deep etchings. The dark valley on the right, named Chasma Boreale, is about the size of the Grand Canyon.
This riven Martian arctic was a mystery to scientists for over forty years. But data from NASA’s Mars Reconnaissance Orbiter has given researchers some important clues to how the ice spirals formed. Their findings appear in two papers published in the journal Nature.
Data from Mars now points to both the canyon and spiral troughs being created and shaped primarily by wind. Rather than being cut into existing ice very recently, the features formed over millions of years as the ice sheet grew. By influencing wind patterns, the shape of underlying, older ice controlled where and how the features grew. [NASA] Read More