According to new studies, researchers discovered that Mars once have been covered in ice sheets like those in the Arctic, rather than just flowing rivers.
Researchers examined thousands of Martian valleys, to generate detailed information on their construction. They found that Mars has valleys that look remarkably similar to ours in the poles, with only a small number of the valley networks appearing as if they had been formed by surface water erosion. They seem to have come about as a result of extensive erosion from water draining beneath an ancient ice sheet.
"For the last 40 years, since Mars's valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys," said Grau Galofre, who led the research published in Nature Geoscience, in a statement.
"But there are hundreds of valleys on Mars, and they look very different from each other. If you look at Earth from a satellite you see a lot of valleys: some of them made by rivers, some made by glaciers, some made by other processes, and each type has a distinctive shape. Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them."
When the valleys that cross across Mars's surface were spotted and further studied, it led to hope that rivers once flowed across its surface. Which then came to the idea that the planet was once wet and warm, with rainfall and oceans.
But studies found that the water that previously existed on the planet might have been in a similar way to the ice that formed similar channels in the Canadian Arctic Archipelago. Following the new discoveries, it is believe that it might have been helpful to any alien life that might once have lived on ancient Mars due to the fact that the ice sheets would offer protection. The formation of the ice sheets would have allowed the water underneath to stay stable as well as serving as a barrier against the solar radiation that is thought to have once bombarded the Martian surface.
"Climate modelling predicts that Mars' ancient climate was much cooler during the time of valley network formation," said Galofre. "We tried to put everything together and bring up a hypothesis that hadn't really been considered: that channels and valleys networks can form under ice sheets, as part of the drainage system that forms naturally under an ice sheet when there's water accumulated at the base."