It was 1972 when the Mariner 9 probe, in its photographic exploration of the Martian soil, sent images of a special formation, later called “Inca City”, to Earth. Precisely in this region, already mysterious due to the rock structures that They are reminiscent of the ruins of ancient Inca citiesthese other equally “strange” black spider-like structures have been observed.
Inca City
These are rock structures that are reminiscent of the remains of Inca cities, arousing special curiosity about the possible presence of intelligent life forms on the nearby red planet.
NASA’s Mariner 9 probe was the first probe to pass by the red planet. Leaving Earth on May 30, 1971, after 167 days of travel she entered orbit around Mars, revealing the presence of volcanoes and canyons.
Till the date, The origin of these structures is still not well understood.either originating as subsequently petrified sand dunes or as a result of lava seeping from fractures in the ground.
The ExoMars mission
In recent days there has been talk of Ciudad Inca again. In fact, it was discovered that this same area of the planet Mars, located in the south polar region, was covered by “black spiders”up to a kilometer in size. The images were taken and sent to Earth by the Trace Gas Orbiter probe. The international ExoMars mission, of which Italy is the main partner, is divided into two phases.
The first phase involved the probe flying over the Martian surface to detect traces of methane and other gasesbut also to detect traces of active lifestyles in the planet.
The first phase also involved release and descent of the Schiapparelli module, which was however destroyed in the final landing phase. The second phase consists of landing of a rover on Martian soilthe Rosalind Franklin, for “in situ” exploration.
The second phase of the ExoMars mission was delayed significantly due to the war in ukraineas Russian launch and telemetry partner Roskosmos withdrew from the project.
The black spiders in the Inca City
Just like the Earth, The planet Mars also has an inclined axis of rotation with respect to the orbital plane (about 25 degrees compared to 23 on Earth). This circumstance implies the alternation of seasonsfour like on Earth but each one of double duration (6 months), being The Martian year is twice as long as the Earth year.
Mars’ atmosphere, made up of 95% carbon dioxide, is much thinner than Earth’s. For this reason, diurnal fluctuations in surface temperature are highbetween -140 ºC at night and 20 ºC during the day.
Due to low winter temperatures, Atmospheric carbon dioxide tends to condense on the surface forming a layer of ice. Starting in spring, when the surface begins to receive a greater flux of solar radiation, the carbon dioxide ice, instead of melting, sublimates, that is, CO2 It goes directly from the solid state to the gaseous state.
The sublimated gas at the base of the ice layer exerts such pressure that it manages to fracture the frozen layer that covers it and emerge to the surface in the form of fountains or geyserscarrying the dark material below.
As a result, in the underlying ice a spider-shaped crack structure is formed that measure between 40 meters and a kilometer.
Similar structures had already been observed by Mars Express probe near the Inca Citybut not with the same detail as those observed by the ExoMars probe.
