Dramatic dry river canals with a width of more than one kilometer and a depth of 650 feet are found on Mars, showing how the Red Planet once hosted liquid water on its surface.
Today we know Mars as a barren desert, but about 3.4 billion years ago, the Red Planet was flooded in blue, with a large ocean in its northern hemisphere, lakes and many curved rivers. During its ancient past, Mars had a thick and warm atmosphere allowing the planet to keep liquid water on the surface. Observations from satellites in orbit around Mars and surface rummers have provided evidence of this, whether in the form of dry river beds or loose deposits requiring water to form.
Image: ESO / M. Kornmesser / N. Eventually, however, the thick Martian atmosphere evaporates, and along with it the surface waters of the planet. Today visible evidence of this water can still be seen as frozen ice on the poles.
New photos, released today by the European Space Agency (ESA), offer further evidence of the Martian's water past. The region shown in the photos is a system of valleys located in the southern mountains, just east of a large crater called Huygens. The photos taken with the ESA Mars Express satellite at the end of last year show an ancient, heavily crafted area that despite signs of erosion still shows signs of leakage. the valley was taken on November 19, 2018. The ground resolution is approximately 14 meters per pixel. The north is shown to the right.
Image: ESA / DLR / FU Berlin
Topographic color code of the region. Areas of lower altitude are shown in blues and purple, while the higher regions appear in white, yellow and red areas Image: ESA / DLR / FU Berlin
Water once flowed down from the north from right to left in the photo), creating rivers up to two kilometers (1.2 miles) wide and up to 200 meters deep (650 feet), according to ESA. Today, the valley is smooth and fragmented, but its former status as a riverbed is clearly visible. ESA explains further:
In general, the valley system seems to branching out considerably, forming a model resembling tree branches from a central trunk. This type of morphology is known as "dendritic" – the term derives from the Greek word for dendron and it is easy to see why. From the central valley, different canals are formed, forming small tributaries that are often separated again on their way out
This type of dendritic structure is also observed in Earth's drainage systems. A particularly good example is the Yarlung Tsango River, which traverses its way from a source in western Tibet through China, India and Bangladesh. In the case of this image of Mars, these branching canals were probably formed by the flow of surface waters from a once strong river flow combined with extensive rainfall. It is believed that this stream has cut the existing terrain on Mars, creating new paths and carving a new landscape.
The presence of fast ancient water on Mars raises many questions. What was the source of this hurrying water? Was it caused by the melting of the glaciers or the water was poured out of the surface? Or is the rain generating running water? And how long did this water last before it dried out? Is it important that this water contributes to the living conditions of Mars and whether life has appeared on the planet?
These questions remain unanswered and serve as calls for more research to be done on Mars. Fortunately, NASA's brand and InSight ship continue to collect valuable data, including NASA's Mars Reconnaissance Orbiter and ExoMars Trace Gas Orbiter at ESA and Mars Express. Besides, we also have the forthcoming ExoMars mission to look forward to, which will include the newly-selected Roel Franklin.