NASA just recreated 'spiders' seen on Mars in a lab on Earth

When spiders made an appearance on Mars, everyone was shocked. What were those black creepy things on the red planet? They weren't actually real spiders, but just another phenomenon that happens there. Satellite images show these tendrilled shapes on Martian soil, and look rather eerie.

These spiders, known as araneiforms, are made from dust and appear only in the southern polar region of Mars in the planet's spring.

Scientists haven't known much about their formation, including how they come about every Martian year. Now, they have created these spiders in the lab, and hope to learn more about the alien landscape of the red planet.

"The spiders are strange, beautiful geologic features in their own right," says planetary scientist Lauren Mc Keown of NASA's Jet Propulsion Laboratory. "These experiments will help tune our models for how they form."

On Mars, the cold, frigid conditions freeze carbon dioxide into ice. While this is not a natural occurrence on Earth, itcan be artificially made and is known as dry ice.

Mc Keown and her colleagues theorise that the Martian spiders might be a result of frozen carbon dioxide turning straight into a gas. Notably, carbon dioxide does not have a liquid form.

This explanation is known as the Kieffer model, named after geophysicist Hugh Kieffer. Scientists say that when it is cold on Mars, carbon dioxide from the atmosphere freezes on the ground. In springtime, the temperatures rise, and this carbon dioxide ice returns to its gaseous state.

This is possible to happen from the bottom of a deposit of ice, at which point the darker Mars dirt beneath begins absorbing the heat. The sublimated gas gets trapped under the slabs of ice above. Since the gas now has nowhere to go, pressure builds and the ice cracks in a small explosion.

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The carbon dioxide gas escapes through these cracks, along with darker, dusty material. After all the ice disappears, a dark, spider-like scar is all that is left behind.

Creating Mars spiders in a lab

The researchers recreated the phenomenon in the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE, which can replicate the temperature and atmospheric pressure of Mars.

They replicated the dirt on Mars by mixing certain minerals and cooled it in liquid nitrogen. They placed it in the chamber, which had been tuned to the pressure and temperature conditions of Martian winter.

Then they released carbon dioxide into the chamber and it froze onto the simulant. The chamber was then warmed up and following multiple efforts to achieve the right conditions in the chamber, the ice finally exploded.