Written by Noah Martin, Ph.D. student and Candice Bedford, Research Scientist at Purdue University
While much of Perseverance’s work focuses on ancient rocks that record Mars’ long-lost rivers and lakes, megaripples offer a rare opportunity to examine processes that are still shaping the surface today. Megaripples are sand ripples up to 2 meters (about 6.5 feet) tall that are mainly built and modified by wind. However, when water in the atmosphere interacts with dust on the ripple surface, a salty, dusty crust can form. When this happens, it is much harder for the wind to move or shape the megaripple. As such, megaripples on Mars are largely considered inactive, standing as records of past wind regimes and atmospheric water interactions over time. However, some have shown signs of movement, and it is possible that periods of high wind speeds may erode or reactivate these deposits again.
Despite Mars’ thin atmosphere today (2% of the Earth’s atmospheric density), wind is one of the main drivers of change at the surface, eroding local bedrock into sand-sized grains and transporting these grains across the ripple field. As a result, megaripple studies help us understand how wind has shaped the surfac …