NASA’s Curiosity rover has been studying “tessellated structures” on the Red Planet—these being ridges reaching 1–2 meters in height with sandy depressions situated between them. Such formations extend for kilometers, and their presence suggests that ancient groundwater flowed in this region more recently than previously assumed. This finding consequently raises new questions regarding the duration for which microbial life could have persisted on Mars.
When viewed from space, these tessellated features resemble colossal spiderwebs. Specialists have determined the formation process occurred as follows: groundwater permeated fissures in the rock, depositing minerals. These minerals solidified the sections that became the ridges, while the areas left unreinforced were subsequently eroded away by the wind over time.
Before the rover’s arrival, these natural formations had never been observed up close. The vehicle, roughly the size of an SUV and weighing 899 kg, carefully navigated the narrow crests, facing the risk of sinking into the loose sand. Mission control, managed by engineers at NASA’s Jet Propulsion Laboratory, is responsible for charting its traverse paths.
The location of these structures on the slopes of Mount Sharp, a 5-kilometer peak composed of strata from various geological eras, particularly drew the attention of experts. The higher the rover ascends, the more distinct the evidence of a gradual climatic desiccation becomes. However, tessellated ridges are still present at substantial elevations, implying that groundwater lingered here longer than current estimates suggest. Consequently, conditions suitable for microbial existence might have endured much later than the period when rivers and lakes vanished.
Rock samples have also provided significant information. Clay minerals, which form in the presence of water, were detected within the ridges, whereas carbonates, typically resulting from the evaporation of mineral-rich solutions, were found in the depressions. Adding another layer of evidence, concretions—spherical mineral inclusions that serve as indicators of ancient water flow—were observed across different zones of the structure.
A subset of the samples underwent intensive scrutiny: they were heated and treated with chemical agents so the rover’s instruments could search for organic molecules—the carbon-based compounds fundamental to life. This suite of investigations aims to determine if Mars maintained habitability for microorganisms for a longer span than initially hypothesized.
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