What Is It Really About?

Mars is a planet that is not very active geologically: its internal dynamo is at a standstill, its tectonic activity is low and its atmosphere is so thin that the atmospheric pressure at the surface is too low to allow water to remain in the liquid state. It is a very inhospitable planet, and it is perhaps for this reason that it enjoys a quite mysterious aura.

Already in the 1970s, the first images sent back by the Viking probes showed what looked like a human face carved in the rock on the plains of Cydonia. In reality, NASA ended up concluding that it was a play of light and shadow, but the damage was done: the idea that Mars could harbor traces of a vanished civilization was planted in the collective imagination, and, in certain slightly hallucinated circles, she never really left.

Now imagine what happens when images of a pyramid-shaped structure taken by the Mars Reconnaissance Orbiter probe, began to circulate on the web. Located at the bottom of Candor Chasma, it was first photographed in 2001, but has just resurfaced on social media. In less than a week, we have seen a surge of videos on TikTok and Instagram; some for informational purposes, others… much less, as you can see below.

A pyramid without a builder

This pyramid is a geological formation, called the “Candor Tetrahedron”: 290 meters in diameter and 145 meters high (see below). It was captured in detail by the HiRISE instrument (High Resolution Imaging Science Experiment), a camera so powerful that it can distinguish objects less than one meter from 300 kilometers above sea level. Its edges are irregular, its three faces uneven, and its sides covered with wrinkles. betray its natural origin at first glancewhich did not prevent some from seeing a Martian replica of Giza or the trace of alien life.

We can clearly see the intervention of the human hand in the image, can’t we? © NASA / JPL-Caltech / UArizona

Candor Chasma, the canyon in which it stands, is one of the largest canyon systems in the Solar System. Shaped over billions of years, it owes its current morphology to the action of water and wind, landslides and volcanic activity that Mars experienced in its past.

Geologists have listed dozens of formations called “ positive relief knobs »: buried rock structures, harder than the surrounding rock which surrounded them, and which erosion has gradually exposed by razing everything around them. The Candor Tetrahedron is one example among others, a little more imposing than average and a little better cutbut that’s about it.

As you can see in the image above, when you zoom out, it blends perfectly into the landscape and is nothing more than a small mound at the bottom of the canyon. If the Tetrahedron (or its like) still survives, it is only because its density and its mineralogical composition allowed him to resist a little longer than the layers of soft sediments which surrounded it.

Nothing to worry about, even if from a geological point of view, the phenomenon is interesting: it perfectly illustrates the concept ofdifferential erosionwhich designates the release by the wind of hardened rock masses formerly embedded in a much more friable sedimentary matrix.

If we can see a pyramid there, it is because the human mind must juggle its small cognitive biases, one of which is very well known: pareidolia. It pushes our brain to perceive familiar shapes where none exist : a face in the clouds, in the folds of a curtain or a sheet, a human silhouette appearing in a shadow, or as here a supposedly human building in a desert of dust. If you’re not convinced, know that Cerro Tusa in Colombia and the Guizhou Mountains in China produce exactly the same kind of illusion on Earth, without anyone having yet had the idea of summoning an extraterrestrial civilization there. But after this little reading, there is little chance that you will still be convinced by conspiracy theories.