Scientists explain why there are ‘spiders’ on Mars

By Dean Murray via SWNS

David Bowie was right, there are spiders from Mars.

Incredible images taken by the ESA’s Mars Express and ExoMars Trace Gas Orbiter (TGO) spacecraft shows distinctive arachnid shapes.

However, the creepy crawlies are actually small, dark features that form when spring sunshine falls on layers of carbon dioxide deposited over the Red Planet's dark winter months.

The phenomenon was viewed at the outskirts of a part of Mars nicknamed Inca City in the southern polar region, so-called as the linear, almost geometric network of ridges are reminiscent of Inca ruins.

ESA says: "The sunlight causes carbon dioxide ice at the bottom of the layer to turn into gas, which subsequently builds up and breaks through slabs of overlying ice. The gas bursts free in Martian springtime, dragging dark material up to the surface as it goes and shattering layers of ice up to a meter thick."

The emerging gas, laden with dark dust, shoots up through cracks in the ice in the form of tall fountains or geysers, before falling back down and settling on the surface. This creates dark spots of between 45m and 1km across.

ESA say: "This same process creates characteristic ‘spider-shaped’ patterns etched beneath the ice – and so these dark spots are a telltale sign that spiders may be lurking below."

Another ESA’s Mars explorer, the ExoMars Trace Gas Orbiter (TGO), has imaged the spiders’ tendril-like patterns especially clearly. The spiders captured by TGO lie near, but outside, the region shown in the new Mars Express image.

The Mars Express view shows the dark spots on the surface formed by escaping gas and material, while the TGO perspective also captures the spidery, web-like channels that are carved into the ice below.

Mars Express has revealed a great deal about Mars in the last two decades and counting. The orbiter continues to image Mars’s surface, map its minerals, explore the composition and circulation of its atmosphere, probe beneath its crust, and study the Martian environment.