AI Insight
Scientists have discovered that active gullies on Mars, which appear to change over time and resemble water-carved features on Earth, are likely formed by carbon dioxide frost transitioning into a fluid state rather than liquid water. This finding resolves a puzzling observation since Mars is too cold and has too thin an atmosphere to support liquid water on its surface. Research by Apolline Leclef and colleagues at Université Paris-Saclay demonstrates that CO2 frost provides a viable mechanism for the formation and evolution of these dynamic Martian surface features.
Why it matters
This research fundamentally changes our understanding of active geological processes on Mars and reduces the likelihood that these particular gullies indicate recent liquid water activity. The findings have implications for future Mars exploration strategies and the search for potentially habitable environments on the planet.
Understand the Science
Scientists were shocked when they received the first images of Martian gullies. They were even more shocked as those gullies appeared to change over time. Their similarities to gullies seen on Earth were uncanny, but all of Earth’s gullies are formed by water runoff, and Mars is too cold and has too sparse an atmosphere to have liquid water on its surface. Whatever has been causing those changing gullies couldn’t have been water, so what was it? A new paper from Apolline Leclef of the Institut d’Astrophysique Spatiale at Université Paris-Saclay and her colleagues, available on the arXiv preprint server, shows how they are likely caused by CO2 frost turning into a fluid.
Source: What's carving active gullies on Mars? It's not water