During the winter months on Mars, carbon dioxide ice accumulates and forms a thin, icy layer on the landscape. Then, when springtime arrives, the sunlight penetrates through the icy layer and triggers a transformation that leaves the surface looking like it has spiders scuttling across the ground.

This phenomenon is one that has not been observed on Earth

“Rather than being actual spiders, these small, dark features form when spring sunshine falls on layers of carbon dioxide deposited over the dark winter months,” ESA explained in a statement. “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 metre thick,” the space agency explained.