China’s Zhurong rover has revealed strange structures beneath the surface of Mars that offer new clues about the evolution of the red planet’s climate.
These are 16 buried polygonal structures located in the vast basin of Utopia Planitia. Scientists believe that these formations were created by the shrinkage of the terrain due to the cycle of freezing and thawing, a process that may have occurred about 3 billion years ago.
What are the structures?
Using the ground-based radar of the Zhurong rover, scientists identified these polygonal structures deep inside the planet, about 35 meters below the surface. These formations are arranged horizontally in a length of almost 2 kilometers.
What makes this discovery even more interesting is the nature of these formations: while on Earth some similar structures, such as the famous Giant’s Causeway in Northern Ireland, are the result of volcanic activity, on Mars there seems to be no evidence that they are polygonal structures discovered by Zhurong arose in a similar way.
According to the scientists, the polygonal formations would have been created as a result of the accumulation of sediments and thermal processes that marked the Martian basin in the past.
Extreme temperature fluctuations in Mars’ early atmosphere, aided by its ancient axial tilt, could facilitate intense freeze-thaw cycleswhich in turn would cause contractions on the surface that led to these geometrical formations. Therefore, this finding suggests that the planet had a much more complex and varied climate history than previously thought.
The most extreme period
Another fascinating aspect of this study is the suggestion that early Mars may have had a greater obliquity (ie steeper axial tilt) than it does today. This change in slope would cause much more extreme periodswhich may have played a vital role in the geological processes that formed these structures.
Over the millennia, the tilt of Mars has decreased, leading to the milder seasons it experiences today. However, traces of those stormy times remain engraved in its soil.
What is Zhurong’s mission?
The Zhurong rover, which landed on Mars in 2021 as part of China’s Tianwen-1 mission, has been instrumental in this and other investigations. It is equipped with a number of cutting-edge scientific instruments, including a ground-penetrating radar that allows scientists to observe up to tens of meters below the surface, Zhurong was crucial to understanding the internal structure of the red planet.
Self-portrait from October 2021 Zhurong on Mars next to its descent platform.
Unlike other missions focused on surface exploration, such as those of the American rovers, Zhurong specialized in subsurface analysis, which sheds new light on the hidden layers of Mars. The planet still holds many mysteries, but explorers like Zhurong step by step continue to uncover its secrets hidden beneath the red dusty surface.
