New images from ESA’s Mars Express show a beautiful example of a network of dry river valleys on Mars, a sign that water once flowed on the surface of the red planet.
Images from ESA’s Mars Express satellite show a branching, desiccated system of trenches and valleys, signs of ancient water flow that hint at a warmer, wetter past for the Red Planet.
It is a system of valleys in the southern highlands of Mars, located east of a large and well-known impact crater called Huygens, and north of Hellas, the largest impact basin on the planet.
Having between 3.5 and 4 Billion years, the southern Martian highlands are some of the oldest and most cratered parts of Mars, where many ancestral signs of water flow are observed.
As explained by experts, the topography of this region suggests that water flowed downhill from the north, forming valleys up to two kilometers wide and 200 meters deep while doing so.
These valleys are evident today, even after having suffered a significant and strong erosion since they were formed.
This erosion is visible in the form of broken, softened, fragmented and dissected valley edges, especially in valleys that extend from east to west, explains a statement by the European Space Agency.
This type of dendritic structure is also observed on Earth.
A particularly good example is the Yarlung Tsangpo River, which winds from its source in western Tibet through China, India, and Bangladesh reports the European Space Agency.
In the case of this Martian image, the branching channels were probably formed by the runoff of water from the surface of a once-strong river, combined with a large amount of rain.
It is believed that this flow has crossed the existing terrain on Mars, forging new roads and carving a new landscape.
While it is not clear where all this water came from – pre-precipitation, groundwater, melting glaciers? – all this required a much warmer and waterier past for Mars than the planet we see today.
In general, the system of valleys seems to branch out significantly, forming a pattern similar to branches of trees that come from a central trunk.
Several channels separate from the central valley, forming small tributaries that often divide again on their outward journey.