Ancient Mars Covered In Ice Sheets, Not Rivers, Research Suggests

It's widely believed that ancient Mars was a wet and warm paradise, but new findings effectively throw cold water on this hypothesis. Apparently, the Red Planet was a barren land of ice sheets.

That's the conclusion of new research that argues what the Red Planet really looked like during its first billion years by analyzing more than 10,000 segments of valleys on Mars. Scientists were inspired by the subglacial channels in the Canadian Arctic Archipelago, and their new analysis claims that some Martian valleys may have been formed by a similar process.

"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," Anna Grau Galofre, lead author of the new research, said in a statement. "Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them."

According to the researchers, one of those processes could be meltwater running between an ice sheet and the ground beneath it. That kind of erosion causes a different valley pattern compared to the one that's caused by free-flowing water. Many Martian valleys that have been studied so far matched the ice sheet formation behavior.

The team led by Grau Galofre studied maps of Mars produced by data from the Mars Orbiter Laser Altimeter. A program was developed in which six different characteristics were integrated with each of more than 10,000 valley segments, then compared each cluster with attributes based on four different formation scenarios.

The analysis found that out of 66 networks, 22 were found to have matched the patterns formed by meltwater flowing beneath a glacier, 14 matched patterns formed by free-flowing rivers, and nine matched patterns formed by glaciers themselves. The rest were left unidentified as they did not reveal distinct enough matches, the team noted.

Valleys that appeared to have been formed by meltwater flowing across glaciers were all over Mars, but those formed by rivers were mostly found in a particularly ancient region of Mars, the Arabia Terra, NASA said.

Melted water running under a glacier and rivers suggest a key difference in their environment: temperature. With these new findings, the team believes that early Mars may have been cooler in its distant past than previous hypotheses suggest.

The paper is published in the journal Nature Geoscience.