Extensive networks of valleys are visible in the southern highlands of the Martian region. They hint that the planet was previously wet and warm. New data show that water could flow even during “ice ages”
All who try to understand the ancient Mars, stumble upon mixed tips. Watershed valleys and lake basins clearly show that earlier liquid water flowed over the surface. But early-period climate models hint at temperatures below zero.
A recent study from Brown University creates a bridge between warm and icy periods. Analysis shows that even with severe frosts, daytime summer temperatures could rise above zero and lead to the melting of glaciers. There was little melt water, but it was enough to create formations observed on the surface.
This conclusion scientists pushed the situation in the dry Antarctic valleys on Earth, where seasonal temperature fluctuations lead to the creation of lakes. The modern Martian climate model suggests that the ancient atmosphere for the most part consisted of carbon dioxide. Because of this, we see a frosty Mars, but 4 billion years ago, networks of valleys formed on the southern elevation. In the past, the atmospheric layer was denser and could contain greenhouse gases. As possible options, different axial inclination and eccentricity index were considered. The model showed scenarios where the ice covered areas near the locations of the valleys.
In order for the mechanism to explain the presence of valleys, it needs to guarantee the necessary water volume and speed of its arrival. It turns out that the model works, and the degree of eccentricity is located in the range of possible orbits of the Red Planet 4 billion years ago.
But scientists do not stop and consider all possible mechanisms. Among them are volcanism and chemical influences.