New research could explain how river-like channels formed on Mars

13 October 2017

Artists impression of NASA’s Phoenix Mars Lander landing on the surface of Mars

An artist’s impression of NASA’s Phoenix Mars Lander during a Mars winter.
(Credit: NASA)

A new research paper published today could help to explain how the mysterious channels, which look like dried-up riverbeds, could have formed on the surface of Mars.

The hunt for extra-terrestrial life is one of the key outstanding mysteries in science – and water is largely regarded as a prerequisite for the development and survival of life. This is why the search for life outside of our planet usually starts as a search for water.

The river-like patterns on Mars’ surface led many to question whether there was once flowing water – and therefore potentially life – on Mars. But despite evidence to suggest water once flowed over the surface of the red planet, it is also well documented that the Martian atmosphere does not have a suitable climate for pure water to remain in liquid form.

Scientists’ conclusions in this new research paper could explain how these Martian channels formed, shedding light on a phenomenon that has perplexed scientists for centuries.

Using the UK’s leading neutron and muon source ISIS, which is based at the Science and Technology Facility Council’s (STFC) Rutherford Appleton Laboratory in Oxfordshire, scientists from Leeds University studied a man-made replica of Martian water.

ISIS senior scientist Dr Alan Soper was part of the research team, and he said: “This research is particularly fascinating because it could help us to answer some of the great mysteries about life on other planets.

“This does not only have implications just for Mars, as this type of liquid is likely to occur elsewhere in the Universe. This research therefore represents a very exciting step forward in the search for extra-terrestrial liquid water – and with it, life.”

In 2008, NASA’s Phoenix Mars Lander discovered perchlorate in the rubble of the planet’s surface, which suggested liquid water might exist below the surface.

The research team used the SANDALS instrument, a neutron diffractometer specifically built for investigating the structure of liquids, to study the structure of the Martian water, known as magnesium perchlorate aqueous solution.

Magnesium perchlorate is used because it has a very low freezing point, which makes it a good substitute when looking at substances found on Mars where the average temperature is around -55 to -60 degrees Celsius.

Neutrons were fired at the solution to allow the scientists to study the perchlorate structure. Neutrons scatter from the hydrogen bonds in solution, and by studying the patterns made by these bonds, the researchers could see the structure of the water inside the perchlorate solution.

Dr Lorna Dougan from the University of Leeds, lead author on the paper, said: “We found these observations quite intriguing. It gives a different perspective of how salts dissolve in water. The magnesium perchlorate is clearly a major contributing factor on the freezing point of this solution and paves the way for understanding how a fluid might exist under the very dry and sub-freezing conditions of Mars.

“This highlights the importance of studying life in extreme environments in both terrestrial and non-terrestrial environments so that we can fully understand the natural limits of life.”

Upon investigation, the researchers found that magnesium perchlorate had a major impact on the water structure in solution, by squashing its structure out of its usual shape – a tetrahedron. By doing this and changing the order of the ions in the structure, it pushes the freezing point of water much lower.

This means that the water is unable to turn into ice, even at really low temperatures. This could therefore explain how these salt solutions, like the one spotted by NASA’s robot, remain liquid on the Martian surface.

The team have therefore shown that aqueous perchlorate solution could provide the ‘transport’ for water to flow across the surface of Mars.

This research was supported by the Engineering and Physical Sciences Research Council.

ISIS

Leeds University

Notes to editors

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