NASA Recreates Mars ‘Spiders’ in Earth Lab

When images from Mars showed strange black shapes resembling spiders, many were startled. These weren’t actual spiders, but a natural phenomenon occurring on the red planet. Satellite pictures revealed these tendrilled formations on the Martian surface, which looked eerie and unfamiliar.

These formations, known as araneiforms, are dust structures that appear in the southern polar region of Mars during its spring season.

For a long time, scientists were unsure how these spiders formed and why they returned each Martian year. But now, researchers have successfully recreated these formations in a lab, hoping to better understand Mars’ unique landscape.

“The spiders are strange, beautiful geological features,” said NASA’s Jet Propulsion Laboratory planetary scientist Lauren McKeown. “These experiments will help refine our models of their formation.”

On Mars, frigid temperatures cause carbon dioxide to freeze into ice—something that doesn’t happen naturally on Earth, though it can be artificially created as dry ice.

McKeown and her team suspect that these Martian spiders are created by carbon dioxide transitioning directly from a solid to a gas, skipping the liquid phase entirely. This process, called sublimation, forms the basis of a theory known as the Kieffer model, named after geophysicist Hugh Kieffer.

According to the model, during the cold Martian winters, carbon dioxide from the atmosphere freezes on the surface. As temperatures rise in the spring, this frozen carbon dioxide sublimates back into gas. This process occurs from the bottom of the ice, where the darker Martian soil beneath absorbs heat. The gas becomes trapped under the ice, creating pressure until the ice cracks in a small explosion.

The gas escapes through these cracks, carrying dust along with it. Once the ice is fully gone, it leaves behind a dark, spider-like pattern on the ground.

 

Recreating the phenomenon in the lab

To test their theory, researchers simulated this process in a laboratory setup called the Dirty Under-vacuum Simulation Testbed for Icy Environments (DUSTIE). This machine can replicate the atmospheric pressure and temperature conditions found on Mars.

They recreated Martian soil by combining specific minerals, cooling the mixture in liquid nitrogen, and placing it in the chamber, which was adjusted to match Martian winter conditions. When carbon dioxide was released into the chamber, it froze on the surface. After multiple attempts to fine-tune the conditions, the ice finally exploded, successfully mimicking the formation of the Mars spiders.