Universe Today
Mars modern landscape is something of a paradox. It's many surface features are very similar to those on Earth that are caused by water-borne erosion. But for the life of them, scientists cannot imagine how water could have flown on Mars' cold and desiccated surface for most of Mars' history. Whereas Mars was once a warmer, wetter place, it has had a very thin atmosphere for billions of years now, which makes water flow and erosion highly unlikely.
In fact, while the surface of Mars periodically becomes warm enough to allow for ice to thaw, liquid water would boil once exposed to the thin atmosphere. However, in a
new study
led by an international team of researchers from the UK, France and Switzerland, it has been determined that a different kind of transport process involving the sublimation of water ice could have led to the Martian landscape becoming what it is today.
The study, which was led Dr. Jan Raack - a Marie Sklodowska-Curie Research Fellow at The Open University - was recently published in the scientific journal
Nature Communications.
Titled "
Water Induced Sediment Levitation Enhances Downslope Transport on Mars"
, this research study consisted of experiments that tested how processes on Mars' surface could allow water transport without it being in liquid form.
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Reull Vallis, the river-like structure captured by the ESA's Mars Express probe, is believed to have formed when running water flowed in the distant martian past. Credit and copyright: ESA/DLR/FU Berlin (G. Neukum)
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To conduct their experiments, the team used the Mars Simulation Chamber, an instrument at The Open University that is capable of simulating the atmospheric conditions on Mars. This involved lowering the atmospheric pressure inside the chamber to what is normal for Mars - about 7 mbar, compared to 1000 mbar (1 bar or 100 kilopascals) here on Earth - while also adjusting temperatures.
On Mars, temperatures range from a low of -143 °C (-255 °F) during winter at the poles to a high of 35 °C (95 °F) at the equator during midday in the summer. Having recreated these conditions, the team found that when water ice exposed to the simulated Martian atmosphere, it would not simply melt. Instead, it would become unstable and begin violently boiling off.
However, the team also found that this process would be capable of moving large amounts of sand and sediment, which would effectively "levitate" on the boiling water. This means that, compared to Earth, relatively small amounts of liquid water are capable of moving sediment across the surface of Mars. These levitating pockets of sand and debris would be capable of forming tje large dunes, gullies, recurring slope lineae, and other features observed on Mars.
In the past, scientists have indicated how these features were the result of sediment transportation down slopes, but were unclear as to the mechanisms behind them. As Dr. Jan Raack explained in a OUNews
press release
:
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Illustration of the ESA Exomars 2020 Rover, which will explore the Red Planet in search for signs of ancient life. Credit:ESA
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Through these experiments, Dr. Raack and his colleagues were able to shed light on how conditions on Mars could allow for features that we tend to associate with flowing water here on Earth. In addition to helping to resolve a somewhat contentious debate concerning Mars' geological history and evolution, this study is also significant when it comes to future exploration missions.
Dr. Raack acknowledges the need for more research to confirm their study's conclusions, and indicated that the ESA's
ExoMars 2020 Rover
will be well-situated to conduct it once it is deployed :
The study was co-authored by scientists from the
STFC Rutherford Appleton Laboratory
, the University of Bern, and the University of Nantes. The initial concept was developed by Susan J. Conway of the University of Nantes, and was funded by a grant from the Europlanet 2020 Research Infrastructure, which is part the
European Union's Horizon 2020 Research and Innovation Program
.
Be sure to check out this video of Dr. Jan Raack explaining their experiment as well, courtesy of The Open University:
