Early Mars was covered in ice sheets according to scientists

Researchers from the University of British Columbia say that a large number of the valley networks guarding the surface of Mars were carved by water melting beneath the glacial ice, not by free-flowing rivers. Many scientists believe that ancient Mars was covered with a large amount of liquid water, including flowing rivers.

Authors behind the new study say that their findings throw cold water on the dominant "warm and wet ancient Mars" hypothesis. That hypothesis postulates rivers, rainfall, and oceans once existed on the red planet. University of British Columbia researchers created a new technique to examine the thousands of Martian valleys on the planet's surface.

The team also compared in their research the Martian valleys to the subglacial channels in the Canadian Arctic Archipelago and uncovered similarities. When you look at similar valleys on Earth, the group says there are differences in them depending on if they are made by rivers, glaciers, or other processes. Each type of valley has a distinctive shape.

They say Mars is similar with valleys that look very different from each other, suggesting many processes were at play to carve them. In particular, the team noted similarity between many Martian valleys in the subglacial channels on Devon Island in the Canadian Arctic. The team says that Devon Island is one of the best analogs on earth for Mars, noting that it is a cold, dry polar desert, and the glaciation is largely cold-based.

In the research, the team analyzed more than 10,000 Martian valleys using a new algorithm to infer their underlying erosion processes. The findings demonstrated that only a fraction of the Valley networks on Mars matches typical surface water erosion patterns. While the team has a different theory on surface erosion for the red planet, they do point out that the environments they believe created the erosion patterns would support better survival conditions for possible ancient life.