Ancient snow or rain on Mars falling on mountains likely carved ridges in the valleys below, according to a new study.
The phenomenon, known as orographic precipitation, has been seen on Earth when wind pushes precipitation uphill, which then flows down. It’s unclear if the Mars precipitation was in the form of water or snow, although the model used in the study assumes snow.
The possible finding on Mars now adds a better understanding of where water came from in the Red Planet, researchers said. Scientists are not sure if Mars’ water came from underground springs or precipitation. This finding weighs more evidence towards precipitation. While the researchers used snow in their modelling, it’s possible some of the snow was periodically melted during planetary warming periods.
"The next step is to do some snowmelt modeling," stated Kat Scanlon, a geological sciences graduate student at Brown University who led the research. "The question is how fast can you melt a giant snowbank. Do you need rain? Is it even possible to get enough discharge [to carve the valleys] with just the snowmelt?"