Seattle, WA – While Mars may not have any insects, recent images captured by an orbiting spacecraft have unveiled an intriguing phenomenon known as ‘spiders’ that appear to move across the planet’s barren surface. These spider-like features are not actual arachnids but rather dark, spindly formations that arise due to non-biological processes influenced by seasonal changes on Mars.
The seasonal shifts on Mars, characterized by extreme cold followed by spring warming, play a crucial role in the creation of these peculiar ‘spiders’. Unlike Earth, Mars experiences seasons differently due to its axial tilt. Winter temperatures on the red planet plummet to below minus 123 degrees Celsius (minus 190 Fahrenheit), causing the majority of substances, including carbon dioxide, to freeze and form deposits of dry ice.
As the cold winter transitions into spring, the frozen carbon dioxide does not melt like regular ice but goes through a process known as sublimation, turning directly into gas. This transformation results in the build-up of pressure beneath the ice deposit, leading to mini explosions on the Martian surface, creating cracks and erupting geysers of dark material from below.
Images captured by the European Space Agency’s Mars Express Orbiter provide a closer look at these dark speckles, resembling freckles scattered on the dusty Martian terrain. The Colour and Stereo Surface Imaging System (CaSSIS) on ESA’s ExoMars Trace Gas Orbiter can detect the spider-like tendrils under the surface of the ice, offering a more detailed perspective on this intriguing phenomenon.
One particular formation on Mars, dubbed Inca City for its resemblance to ancient ruins from above, showcases the widespread presence of these spider-shaped features. As the Martian surface awakens during the warming days of spring, the activity of these ‘spiders’ becomes more pronounced, creating a visually captivating scene of ice cracking open and dust hissing into the air.
Imagining the surreal sight of these mini explosions and the dust swirling above Mars’s surface sparks curiosity about potential future explorations. Perhaps, one day, human explorers on Mars will be able to witness and document firsthand this alien process, providing a unique glimpse into the dynamic nature of the Red Planet.