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'Flowing' water on Mars may be sand and dust: Study

The study is based on observations made with the High-Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.

IANS  |  Washington 

Mars
Mars

Dark features earlier proposed as evidence of flowing on may actually be granular flows, where move rather than liquid water, says a study.

The new findings, published in the journal Nature Geoscience, indicate that the water-restricted conditions that exist on would make it difficult for Earth-like life to exist near the surface of the planet.

The study is based on observations made with the High-Resolution Imaging Science Experiment (HiRISE) camera on NASA's Reconnaissance Orbiter.

The researchers analysed narrow, down-slope trending surface features on that are darker than their surroundings, called Recurring Slope Lineae, or

These features have evoked fascination and controversy since their 2011 discovery, as possible markers for unexpected or brine on an otherwise dry planet.

These features grow incrementally, fade when inactive and recur annually during the warmest time of the year on

are mostly found on steep rocky slopes in the dark regions of Mars, such as the southern mid-latitudes, near the equator and in Acidalia Planitia on the northern plains.

The appearance and growth of these features resemble seeping liquid water, but how they form remains unclear, and this research demonstrated that the flows seen by are likely moving granular material like

"We've thought of as possible flows, but the slopes are more like what we expect for dry sand," said lead author Colin Dundas, a US Geological Survey scientist.

"This new understanding of supports other evidence that shows that today is very dry," Dundas added.

The terminal end of the slopes, said Dundas, is identical to the slopes of sand dunes where movement is caused by dry granular flows.

Water almost certainly is not responsible for this behaviour, which would require the volume of liquid to correspond to the length of slope available, producing more liquid on longer slopes, the study said.

 

First Published: Tue, November 21 2017. 21:22 IST
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