Mars shares many similarities with Earth, as it has valleys, canyons, sand and rocks, all shaped by flowing water over time. While scientists understand that water created these features, the biggest mystery is how and when Mars was able to hold so much water on its surface.

Peter Buhler, a research scientist at the Planetary Science Institute, may have found an answer to this big question. In his research paper, he proposed that carbon dioxide ice settling on Mars’ south polar region could explain how the planet’s largest features, like its biggest lake, valleys and ridges, were formed.

Buhler said, “This model describes the origins of major landscape features on Mars, like the biggest lake, the biggest valleys and the biggest esker system (remnants of rivers that once flowed beneath an ice sheet) – in a self-consistent way. And it’s only relying on a process that we see already today, which is just carbon dioxide collapsing from the atmosphere."

In his paper, published in the Journal of Geophysical Research: Planets, Peter Buhler explained that around 3.6 billion years ago, carbon dioxide from Mars’ atmosphere froze and settled on a layer of water sheet at the poles. This layer acted as a blanket that trapped heat from the planet’s interior and increased pressure on the ice. As a result, half of Mars’ water melted and flowed towards the surface without the warm climate.

The researcher also expanded his model to study how carbon dioxide interacts with the sand and rocks on Mars

“The only way left for the water to go is through the interface between the ice sheet and the rock underneath it. That’s why on Earth you see rivers come out from underneath glaciers instead of just draining into the ground," he explained.

The meltwater from the ice sheet creates rivers beneath the ice, which then leave behind long gravel ridges called eskers. Scientists have previously found many eskers near Mars’ south pole and their sizes match Buhler’s model.

He believes that eskers are clear signs that Mars once had melting ice beneath its surface, which is still a big mystery. While many scientists have tried to figure out how this could happen, the most common explanation has been some form of global warming on Mars. However, he felt that the explanation was not satisfying because the factors leading to warming were unclear.

Source: news18