When we think about Mars, we often imagine cold and unchanging landscapes. But this couldn’t be further from the truth — Mars is actually a planet with active weather systems that literally mold the land.
The High-Resolution Imaging Science Experiment (HiRISE) camera on board NASA’s Mars Reconnaissance Orbiter regularly monitors Mars’ enigmatic dune fields. These fields cover huge swathes of land and by monitoring these fields week after week, measurable changes in the dunes’ distribution and morphology can be seen. Dune monitoring is an important tool for planetary scientists in an effort to understand weather processes on this alien world.
When zooming in on the dunes of Nili Patera, a plain known for its undulating dunes, HiRISE has spotted obvious signs of dune migration, ripple changes and tiny landslides. Although the changes are small over the 16 month monitoring period, they can still be seen by HiRISE’s high-resolution eye.
Probably most dramatic are the changes in the shapes of the ripples that cover the Martian barchan dunes. Over the 16 months, many ripples have smoothed out whereas others have formed and linked up with neighbors. These are all signs that Mars’ weak winds have a huge impact on the fine grains of material — called “regolith” — that makes up the dunes.
So the next time you hear someone say that Mars has “no weather” or that the planet’s landscape is “dead,” point out that active wind-blown processes are shaping and moving entire dune fields across the Martian landscape right this minute and that we have a powerful orbital camera watching aeolian processes at work.