The European Space Agency (ESA) recently shared pictures of the mysterious spider-like clusters on the planet Mars. The space agency has, however, clarified that these spider-like dark features on the Red Planet form “when spring sunshine falls on layers of carbon dioxide deposited over the dark winter months.”Â
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 between 45 m and 1 km across. 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.
Mars Express’s High-Resolution Stereo Camera captured this new view of Inca City and its hidden arachnid residents. The space agency is still not sure exactly how Inca City formed. It could be that sand dunes have turned to stone over time. Perhaps material such as magma or sand is seeping through fractured sheets of Martian rock. Or, the ridges could be ‘eskers’, winding structures related to glaciers.
More about Mars: Mars Colonization: What decades of missions have revealed
