Extraordinary spiderweb-like structures on the surface of Mars have been photographed in unprecedented detail by NASA’s Curiosity rover, with scientists saying the images point to liquid water surviving on the planet far longer than previously thought.
The formations – scientists call them boxwork – look like enormous webs from space but reveal themselves at ground level as a series of ridges and depressions cutting across the Martian terrain.
Each ridge rises roughly one to two metres and the network stretches for miles in every direction, producing a pattern that from above resembles an enormous web.
Scientists believe the structures were created as water moved through cracks in the bedrock, leaving behind mineral deposits that solidified into ridges as the softer rock around them wore away.
What do the Mars boxwork formations reveal about water on the Red Planet?
The BBC reports how Curiosity’s Mastcam recorded the images as the rover climbed Mount Sharp in Gale Crater, giving scientists their first close-up view of terrain they had previously only been able to study from space.
For mission scientist Tina Seeger and her colleagues, the location of the formations is as significant as their appearance.
Their presence high on the mountain implies water was active in this region well beyond the window scientists had previously estimated.
“Seeing boxwork this far up the mountain suggests the groundwater table had to be pretty high,” she told the BBC’s Sky at Night Magazine.
“And that means the water needed for sustaining life could have lasted much longer than we thought looking from orbit.”
She added: “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.”
The team hopes continued study of the boxwork will help establish how long water flowed on Mars, how widely it spread – and ultimately whether conditions ever existed that could have sustained living organisms.