Mars was covered in ice sheets and not rivers as once thought: Western study
This composite photo, created from over 100 images of Mars taken by Viking Orbiters in the 1970s, made available by NASA shows the planet Mars. (NASA via AP)
LONDON, ONT. -- In a new way of thinking, researchers at Western University say ice sheets and not rivers carved the surface of the red planet.
The findings published in Monday's Nature Geoscience go against conventional thinking that rainfall and oceans once existed on Mars.
"Our study challenges the widely held view that most valley networks on Mars were formed by rivers fed by precipitation. While we found evidence consistent with a small handful of valley networks having formed in this way, our observations suggest that the majority formed beneath ice sheets,” said Western's Gordon Osinski, director of Western’s Institute for Earth and Space Exploration and study co-author.
Many Martian valleys and sub-glacial channels are extremely similar to Devon Island in the Canadian Arctic according to the study.
“Devon Island is one of the best analogues we have for Mars here on Earth,” said Osinski.
“It is a cold, dry polar desert and we know the glaciation is largely cold-based.”
Lead author Anna Grau Galofre, a current Postdoctoral Fellow at Arizona State University, developed and used new techniques to examine thousands of Martian valleys.
“For the last 40 years, since Mars’s valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and forming all of these valleys,” said Grau Galofre.
“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.”
But this new information doesn't necessarily mean there was never life on Mars.
An ice sheet would have given more protection and stability of underlying water, as well as providing shelter from solar radiation in the absence of a magnetic field – something Mars once had, but which disappeared billions of years ago.