NASA Photos of Active Martian Sand-producing Region

Written by Cheyenne MacDonald on . Posted in Current News

NASA’s Mars Reconnaissance Orbiter has spotted a potential sand-producing region that could be feeding the red planet’s stunning expanse of dunes.

In a breathtaking new image, the space agency has revealed a look at the sloping sediments near the boundary of Mars’ Southern highlands and Northern lowlands.

The image shows dark material is being eroded from layers of the bedrock in a massive surface depression, indicating the sand grains were not carried there by wind, according to NASA.  The image, captured by MRO’s Context Camera, shows linear markings in the huge depression that appear to slope downward. This helps to tell the story of the processes taking place at the surface.

‘The grains of sand that make up sand dunes on Earth and Mars have a hazardous existence because of the way that they travel,’ NASA explains.

‘Wind-blown sand is lifted above the surface of each planet before crashing onto the ground and bouncing in a sequence of repeated hops, a process called saltation.

‘Sand grains can also roll along the ground as they are blown by the wind, and they are also jostled by other sand grains that are similarly flying across the surface.’

As these impacts repeat, the sand grains are worn down and smoothed out, eventually forming their spherical shape. And, the tiny fragments that break of add to Mars’ dust deposits. Over time, this process destroys the grains entirely – but, the region spotted in the image may help to keep Mars’ dunes going.

‘The fact that we see active sand dunes on Mars today requires that sand particles must be resupplied to replace the grains that are lost over time,’ NASA says.

MARS: A WET PLANET

Evidence of water on Mars dates back to the Mariner 9 mission, which arrived in 1971. It revealed clues of water erosion in river beds and canyons as well as weather fronts and fogs.

Viking orbiters that followed caused a revolution in our ideas about water on Mars by showing how floods broke through dams and carved deep valleys. Mars is currently in the middle of an ice age, and before this study, scientists believed liquid water could not exist on its surface.

In June 2013, Curiosity found powerful evidence that water good enough to drink once flowed on Mars. In September of the same year, the first scoop of soil analysed by Curiosity revealed that fine materials on the surface of the planet contain two per cent water by weight.

Last month, scientists provided the best estimates for water on Mars, claiming it once had more liquid H2) than the Arctic Ocean – and the planet kept these oceans for more than 1.5 billion years. The findings suggest there was ample time and water for life on Mars to thrive, but over the last 3.7 billion years the red planet has lost 87 per cent of its water – leaving it barren and dry.

 As Martian winter gives way to spring, the snow-covered features on the red planet begin to change form, driven by an influx of sunlight. It might sound familiar to the seasonal changes that take place here on Earth – but, in Mars’ northern hemisphere, the snow and ice speckling the landscape is made not of water, but carbon dioxide.

And, when this ‘dry ice’ is exposed to the sun, it creates remarkable patterns across the surface.

It might sound familiar to the seasonal changes that take place here on Earth ¿ but, in Mars¿ northern hemisphere, the snow and ice speckling the landscape is made not of water, but carbon dioxide. And, when this ¿dry ice¿ is exposed to the sun, it creates remarkable patterns across the surface

It might sound familiar to the seasonal changes that take place here on Earth – but, in Mars’ northern hemisphere, the snow and ice speckling the landscape is made not of water, but carbon dioxide. And, when this ‘dry ice’ is exposed to the sun, it creates remarkable patterns across the surface

SNOW ON MARS

As the atmosphere of Mars is cold and thin, water-ice clouds can form despite the limited amount of water vapour compared to Earth. But until now, it had been thought that any snow precipitation that fell from these clouds did so as slowly settling particles, rather than in rapid storms.

A recent atmospheric model, however, revealed that the cooling of water-ice cloud particles during the cold Martian night can create unstable conditions within the cloud, triggering a descending plume of snow.

These turbulent storms, which can only form at night, act to vigorously mix the atmosphere and, in some places, deposit snow on the surface. A recent captured by NASA’s Mars Reconnaissance Orbiter has revealed a look at these features, showing how ice, sand, and gases react to form wave-like designs that ripple across the dunes.

The image was captured on May 21, 2017 by the Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera, according to NASA. At this time, spring was underway in the Northern hemisphere.

‘Over the winter, snow and ice have inexorably covered the dunes,’ NASA explains. ‘Unlike on Earth, this snow and ice is carbon dioxide, better known to us as dry ice.

‘When the sun starts shining on it in the spring, the ice on the smooth surface of the dune cracks and escaping gas carries dark sand out from the dune below, often creating beautiful patterns.

‘On the rough surface between the dunes, frost is trapped behind small sheltered ridges.’

The Martian surface is covered in all sorts of remarkable features that have been brought to light by the spacecraft over recent years. Earlier this summer, an infrared image from MRO showed a look at the worm-like fissures blanketing the floor of a mysterious crater on Mars.

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