- Mars has giant “spiderwebs” on Mount Sharp in Gale Crater. They are a network of geologic ridges and hollows that extend for miles.
- NASA’s Curiosity rover has been exploring these ridges – also called boxwork – for the past six months.
- Ancient groundwater seeping through large cracks formed the intriguing formations, according to scientists.
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A close look at ‘spiderwebs’ on Mars
NASA’s Curiosity rover has been taking a close look at some spiderwebs on Mars. Not webs made by actual Martian spiders, of course, but sprawling geologic formations that resemble spiderwebs when seen from above. The grid-like formations – called boxwork – consist of ridges about 3 to 6 feet (1 to 2 meters) tall with sandy hollows in between them. They extend for miles in the region of Mount Sharp in Gale Crater. NASA scientists said on February 23, 2026, that ancient groundwater likely formed the intriguing features. Their location on the mountain also suggests that the ancient groundwater table was higher in elevation and longer-lived than previously thought.
The groundwater would have flowed through fractures in the bedrock. In doing so, the water left behind mineral deposits. Later, the areas with the minerals hardened into ridges, while the wind gradually eroded away softer rock, leaving behind the standing ridges. Now we still see the vast network of ridges and hollows, even though the water has long disappeared.
Curiosity has been exploring the spiderweb region for about the past six months.
Maneuvering through the ridges
For the rover, maneuvering through the boxwork ridges can be a bit tricky. The rover can roll across the tops of the ridges, but they are not much wider than the rover itself. Also, Curiosity can move down into the sandy areas between the ridges, but it has to be careful not to get stuck. Operations systems engineer Ashley Stroupe at NASA’s Jet Propulsion Laboratory in Southern California is the Curiosity Rover Planner (Drive) team lead. She said:
It almost feels like a highway we can drive on. But then we have to go down into the hollows, where you need to be mindful of Curiosity’s wheels slipping or having trouble turning in the sand. There’s always a solution. It just takes trying different paths.
How did the boxwork ridges form?
The boxwork ridges are located on the slopes of Mount Sharp, which sits in the middle of Gale Crater and is about 3 miles (5 kilometers) tall. So, how did they form there? Similar formations exist on Earth, in fact, but they are usually only a few centimeters tall at most and found in caves or dry, sandy environments.
The higher elevations of Mount Sharp record a drier period in the history of Gale Crater, which was once a lake billions of years ago. The boxwork formations are surprisingly high up the mountain, however. Mission scientist Tina Seeger at Rice University in Houston, Texas, explained:
Seeing boxwork this far up the mountain suggests the groundwater table had to be pretty high. And that means the water needed for sustaining life could have lasted much longer than we thought looking from orbit.
In addition, orbiting spacecraft have also imaged the boxwork from high above. Intriguingly, the images showed dark lines going across the spiderwebs. Scientists said they were likely central fractures. That’s where the groundwater would have seeped up to the surface. Now, seeing them up close, Curiosity has confirmed they are indeed fractures.
Nodules in the spiderwebs
Additionally, Curiosity has also found other evidence for past groundwater in this region. For example, some of the rocks have bumpy textures comprised of small nodules. But there is another mystery to be solved, too. The nodules aren’t where scientists expected them to be, near the fractures. Instead, they’re along the walls of the ridges and on rocks in the sandy hollows. Seeger said:
We can’t quite explain yet why the nodules appear where they do. Maybe the ridges were cemented by minerals first, and later episodes of groundwater left nodules around them.
While the spiderwebs themselves have nothing to do with Martian life, they do provide new clues about water and habitable conditions in Mars’ past. What other discoveries might be hiding in the webs, waiting to be found?
Bottom line: NASA’s Curiosity rover has been investigating “spiderwebs” on Mars. Groundwater formed these grid-like formations of ridges billions of years ago.
Via NASA
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