18/12/2024
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Step into the holidays with this picturesque ‘winter wonderland’ scene at the south pole of Mars, captured by ESA’s Mars Express.
One can almost imagine the soft crunch of crisp snow underfoot, and a landscape bathed in a calming yellowy-orange hue as the Sun shines through ice- and dust-laden clouds.
These images, taken by the High Resolution Stereo Camera on Mars Express, show an enigmatic landscape in the Australe Scopuli region of the planet’s southern hemisphere, not far from the ‘cryptic terrain’ we explored in October.
Here, swirls of carbon dioxide ice and dust layers wrap around the scene, turning the Red Planet white. The contrasting light and dark layers are particularly striking in the exposed faces of hills and valleys. They trace out the distinctive seasonal polar layered deposits characteristic of this region, formed as layers of ice freeze with varying amounts of dust trapped within.
Donning a pair of 3D glasses reveals a view reminiscent of terrestrial ski resorts with a mixture of smooth, steep slopes and tight bends. Or perhaps you’d prefer a sleigh ride, but either way dress warm, because it’s cold outside: -125°C.
Any martian skier or sleigh rider would also need to slalom around hundreds of potential dust jets. That’s because ski season is almost over and it’s beginning to look a lot like spring – or even summer, for this image was taken on 16 June 2022, close to summer solstice at the south pole. Zooming into the main image reveals numerous dark patches where the ice has already sublimated away (turned directly from solid ice into vapour), a sure sign that the Sun’s warming rays have been falling on this region for some time.
When sunlight shines through the translucent top layers of the carbon dioxide ice it warms up the underlying surface. The ice at the bottom of the layer begins to sublimate, creating pockets of trapped gas. The pressure builds up until the overlying ice suddenly cracks, resulting in a burst of gas jetting through the surface. These gas fountains carry dark dust from below, which falls back to the surface in a fan-shaped pattern moulded by the direction of the prevailing wind. The fans can range in length from tens to hundreds of metres.
The process is similar to that which creates the ‘spider’ features presented in another recent Mars Express image release.
An even closer look, in particular in the perspective views, shows that the fans often appear to follow the boundaries between the polar layered deposits. Presumably these boundaries represent zones of weakness, where the escaping dust-laden jets can break through the ice layers more easily.
We may well have missed our chance to make one last ‘Frosty the Snowman’, but it’s still a wonderful time of year on Mars!
The Mars Express High Resolution Stereo Camera (HRSC) was developed and is operated by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). The systematic processing of the camera data took place at the DLR Institute for Planetary Research in Berlin-Adlershof. The working group of Planetary Science and Remote Sensing at Freie Universität Berlin used the data to create the image products shown here.
This post was originally published on here
