NASA’s Curiosity rover has photographed a Martian valley floor covered in polygonal fractures, honeycomb-like shapes that extend in all directions as far as the rover can see. NASA said the field, spotted as Curiosity began climbing a valley nicknamed Valle Grande on Mount Sharp, is far larger than the small patches of similar shapes the mission has recorded before. The release describes the fractures as a familiar sight to mission scientists, but at a scale never seen on the mission.
The 360-degree panorama was captured on June 19 and 20, the 4,930th and 4,931st Martian days, or sols, of the mission. Individual polygons in the field measure about 4 to 8 centimeters (1.5 to 3 inches) across, and the shapes wrap around the sides of a nearby butte nicknamed Miraflores, about 6 meters (20 feet) tall and topped with a thick cap of sand. NASA released a separate image of the butte taken on June 11, showing the surrounding terrain covered in the same surface features, and a close-up of the fractures highlighting their honeycomb texture.
The mission’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California, described the field as one of the most striking landscapes Curiosity has seen in its 14 years on Mars. He said the team measured the shapes and their chemistry and is hopeful the data contain clues to how the features formed.
Some of the polygons the mission has found in the past clearly formed as mud cracks, NASA said. Honeycomb textures can also result from cycles of warm and cold temperatures, or from compression that squeezed water out of sediment after the surface was buried. The agency did not state which process produced the Valle Grande field, and it did not cite a peer-reviewed study tied to the find.
The discovery adds to a list of surprises Curiosity has accumulated since landing on August 5, 2012, including sulfur crystals and shiny meteorites. The rover has been ascending Mount Sharp, a 5-kilometer (3-mile) mountain, since 2014, and has established that billions of years ago lakes and streams dotted the mountain’s lower foothills. That ancient environment had the water, chemistry, and nutrients needed to support microbial life, and the rover has previously found carbon-based molecules believed to be precursors to RNA and DNA, the two nucleic acids that carry genetic information. Scientists have no way of knowing whether those molecules were produced by biological or geological processes; either path is possible, NASA said.
JPL, managed by Caltech in Pasadena, California, built Curiosity and leads the mission for NASA’s Science Mission Directorate as part of the agency’s Mars Exploration Program.
Sources
1. The Verge, “NASA’s Curiosity rover found a ‘sea of polygons’ on Mars”: https://www.theverge.com/science/973314/nasa-curiosity-rover-mars-polygons
2. NASA Jet Propulsion Laboratory, “NASA’s Curiosity Mars Rover Discovers Field of Honeycomb Textures”: https://www.nasa.gov/missions/mars-science-laboratory/curiosity-rover/nasas-curiosity-mars-rover-discovers-field-of-honeycomb-textures/