NASA's Curiosity rover discovered an unusual "web" on Martian soil that had previously been observed only from orbital spacecraft images.

Curiosity — the study of “webbing” on Mars

NASA’s Curiosity rover has been studying a strange section of the Elysium Mountain (informally Mount Sharp) in Gale Crater for almost six months now. On the surface are visible, as‑seen‑from‑space “boxwork” structures: low ridges 1–2 m high, with sandy troughs between them. From orbit they resemble a huge spiderweb spreading out over kilometers.

What the images showed
On September 26, 2025 Curiosity created a detailed panorama of the terrain. Upon closer inspection the rock is composed of many tiny “knots” the size of peas. From afar, especially from satellite orbit, they look like a web that scientists explain as fractures and their mineralization.

How the ridges formed
* In ancient times groundwater seeped through large fractures in the bedrock.
* These waters left behind clays and carbonates, cementing areas around the cracks and creating strong ridges.
* Less‑reinforced zones were eroded by wind over time, forming troughs.
* The dark lines crossing the ridges are central fractures with the highest mineral concentration.

Thus, the hypothesis formulated in 2014 from satellite images was confirmed by Curiosity’s ground investigations. The rover’s fieldwork complemented the picture and added missing details.

New findings
* On the ridges and in the troughs there are bumpy knots not always associated with the central fractures, which may indicate later episodes of water seepage.
* X‑ray analysis showed a distinct mineral distribution: clays dominate the ridges, carbonates dominate the troughs.
* Curiosity collected three soil samples from different parts of the terrain (from the ridge top, from bedrock in the trough, and from a transition zone) and an additional one for “wet” chemistry to search for organic compounds.

What this means
The presence of porous structures linked to ancient groundwater circulation indicates that Mars’ groundwater level was much higher in the past than previously thought. This means wet periods lasted longer, and conditions potentially suitable for microbial life persisted for a long time.

Curiosity’s observations continue to rewrite the history of Martian climate: from active water periods to the gradual transition of Mars into its present cold desert state.