* Astronomy

EPSC09/18: It's a grind to make Mars red
The widespread idea that Mars is red due to rocks being rusted by the water that once flooded the red planet may be wrong. Recent laboratory studies show that the red dust may be formed by ongoing grinding of surface rocks and liquid water need not have played any significant role in the red dust formation process. These findings, which open up the debate about the history of water on Mars and whether it has ever been habitable, have been presented at the European Planetary Science Congress by Dr Jonathan Merrison, of the Aarhus Mars Simulation Laboratory, Denmark.

"Mars should really look black, between its white polar caps, because most of the rocks at mid-latitudes are basalt. For decades we assumed that the reddish regions on Mars are related to the water-rich early history of the planet and that, at least in some areas, water-bearing heavily oxidised iron minerals are present" - Dr Jonathan Merrison.

In their recent laboratory study, scientists at the Mars Simulation Laboratory have pioneered a novel technique to simulate the sand transport on Mars. They hermetically sealed sand (quartz) t samples in glass flasks and mechanically "tumbled" them for several months, turning each flask ten million times. After gently tumbling pure quartz sand for seven months, almost 10% of the sand had been reduced to dust. When scientists added powdered magnetite, an iron oxide present in Martian basalt, to the flasks they were surprised to see it getting redder as the flasks were tumbled.

"Reddish-orange material deposits, which resemble mineral mantles known as desert varnish, started appearing on the tumbled flasks. Subsequent analysis of the flask material and dust has shown that the magnetite was transformed into the red mineral hematite, through a completely mechanical process without the presence of water at any stage of this process" - Dr Jonathan Merrison.

The scientists suspect that, as the quartz sand grains are tumbled around they get quickly eroded and an alteration of minerals through contact ensues. How exactly this happens need to be further investigated through more experimental and analytical work. What is clear though is that the first experiments show that this process occurs not only in air but also in a dried carbon dioxide atmosphere, that is, in conditions that perfectly resemble those occurring on Mars. It may also imply that the reddish Martian dust is geologically recent.

Source: European Planetology Network

Mars' great canyon complex, Valles Marineris, dwarfs the size and splendour of Earth's own Grand Canyon. But while geologists have a formed a fairly complete picture of how the Grand Canyon formed, the mechanisms that carved out Valles Marineris and its component canyons have been a longstanding mystery, with explanations ranging from massive floods to tectonic processes like those that cause earthquakes and build mountains on Earth.

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Mars 'Monolith'

An image of what appears to be a mysterious rocky monument on Mars has excited space junkies around the world.
The 'monolith', was snapped from 165miles away using a special high resolution camera on board the Mars Reconnaissance Orbiter.
After being published on the website Lunar Explorer Italia, it set tongues wagging with space buffs questioning whether there was once life on the Red Planet.
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Martians invade Glacier - Mars scientists visit park to study, compare rocks
When the Martians landed in Glacier National Park, with tiny lenses magnifying their eyeballs, they could not see the mountains for the rocks.
Glacier Park, of course, is no analogue for Mars; it has goats, after all. But it does provide a practice ground of sorts, a place where scientists can presume a certain amount of familiarity when learning how to read rock, and how to infer what was by what is.
That, in fact, is exactly why 30-some self-described Martians - members of the team that operates the camera on the Mars Reconnaissance Orbiter - landed here for their week of summer work.

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