Where Do These “Spiders” on Mars Come From?

[Cet article a initialement été publié le 27 avril 2024]

At the beginning of March, a probe had immortalized an object that looks like a surfboard above the moon. It was actually a Korean spacecraft. This time, it is the European probes Mars Express and Exomars Trace Gas Orbiter (TGO) who sent clichés of “spiders” present on the soil in the southern polar region of March.

Obviously, there are no spiders on Mars, nor other living elements. Besides, you just have to take a look at the photo scale to realize that each arachnid is between 45 m and 1 km wide!

In the spring, ice transforms into gas

According to the European Space Agency (ESA), which publishes these shots, these small dark structures are formed when the spring sun falls on the layers of carbon dioxide deposited during the winter. Sun light then transforms carbon dioxide ice at the bottom of the gas layer, which then accumulates and breaks the overlying ice plates. The gas escapes in Martian spring, causing dark materials to the surface and breaking layers of ice that can reach a meter thick.

The emerging gas, loaded with dark dust, pierces the cracks in fountain -shaped ice or geysers, before falling back and depositing on the surface. This creates dark spots with a diameter between 45 m and 1 km.

Inca ruins on Mars?!?

When we take the image as a whole, we discover that these “spiders” are on the outskirts of a part of Mars nicknamed the Inca city. As we can see on the shots, the line of linear crests, almost geometric, obviously recalls the Inca ruins, like the legendary Machu Picchu. Officially, this region is known as Angustus Labyrinthus, and it was discovered in 1972 by NASA Mariner 9 probe.

© ESA, DLR, Fu Berlin

But it is the first time that it has been visible from this angle, with a high resolution camera. If the origin of “spiders” is known, on the other hand, the birth of this Inca city remains mysterious. Scientists evoke sand dunes transformed into stone over time. But it could also be “eskers”, winding structures linked to glaciers.

A “city” at the bottom of a crater

Be that as it may, the city finds itself at the heart of a large circle of 86 km in diameter, and the experts suspect it is located is inside a large crater which itself formed when a rock from space, undoubtedly a meteorite, crashed on the surface of the planet.

This impact probably caused fault undulations in the surrounding plain, which were then filled with rising lava and have been used over time.