It’s ‘spider’ season on the Red Planet. There are no actual spiders on Mars–that we know of–but arachnid-shaped black spots dot some parts of our celestial neighbor every spring.
[Related: Mars’s mascara-like streaks may be caused by slush and landslides.]
The European Space Agency (ESA) released new images of these seasonal eruptions in a formation called Inca City in Mars’ southern polar region.
How do Martian ‘spiders’ form?
Mars has four distinct seasons, similarly to Earth. Each Martian season lasts roughly twice as long as a season here. According to the ESA, these spider-like marks appear in Martian spring when sunlight falls on layers of carbon dioxide that have been deposited over the dark Martian winter. The sunlight causes carbon dioxide ice at the bottom layer to turn into gas. The gas builds up and eventually breaks through slabs overlying ice around Mars’ poles. When they burst free, the dark material is dragged up to the surface as it travels and shatters layers of ice that are up to three feet thick.
The emerging gas is full of dark dust and shoots up through cracks in the ice similar to a fountain or geyser. The gas then travels back down and settles on the surface. The settling gas creates dark spots which range from 0.3 to 0.6 miles across. This same process creates the spider-shaped patterns that are etched beneath the ice.
The image was captured by the CaSSIS instrument aboard the ESA’s ExoMars Trace Gas Orbiter (TGO). CaSSIS stands for Colour and Stereo Surface Imaging System and it was built at the University of Bern in Germany. It creates high resolution images designed to complement data collected on Mars. It is made up of a telescope and focal plane system that are mounted on a rotation mechanism and has three electronics units that relay…
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