A striking pattern
NASA's Curiosity rover has found the largest patch of polygon-shaped ground fractures it has ever seen on Mars. The discovery came in a valley called Valle Grande, on the lower slopes of Mount Sharp inside Gale Crater.
The fractures form a honeycomb of cracks across the ground. Similar patterns appear on Earth when wet mud dries out and shrinks. Scientists say the shapes can also form through repeated freezing and thawing of the soil.
Clues to a wetter Mars
Polygon fractures are a strong clue that water once shaped this part of Mars. The patterns suggest the ground was wet long ago and then dried under a changing climate.
Curiosity has spent years climbing Mount Sharp. Along the way it has found evidence of ancient lakes, streams, and shifting environmental conditions. The new site adds another chapter to that story.
The team says the size of the polygons is unusual. Some of the cracks are large enough to be seen clearly from orbit. That makes the site a useful target for comparing rover data with images from Mars orbiters.
What comes next
The rover team plans to study the polygons in detail over the coming weeks. Curiosity will take close-up images and use its instruments to measure the chemistry of the cracked ground.
"This is exactly the kind of terrain we hoped to find," a mission scientist said. The data could help researchers understand how long liquid water lasted on Mars and when the planet turned cold and dry.
Curiosity landed in Gale Crater in 2012. It was designed for a two-year mission but is still running more than a decade later. Its findings continue to shape how scientists picture the early history of Mars.