NASA's Curiosity Rover Spots Odd Pit Formations on Mars, Not Footprints, Team Says

Scientists studying images from NASA's Curiosity rover have identified an unusual set of surface features on Mars that some early reports described as resembling footprints, according to a mainstream news source reporting on the images. The formations were spotted as Curiosity explored Mount Sharp, the large mountain that rises from the floor of Gale Crater, according to a mainstream source describing the discovery.

The features are described as broad, shallow pits unlike anything researchers had previously observed on the Red Planet, the report said. Small pits and depressions are relatively common on Mars, according to researchers, who say they can form when harder nodules or pebbles embedded in rock gradually erode away, leaving a hollow behind. But researchers said the newly spotted pits are notably wider and shallower than those seen before, and they were unable to identify any obvious objects that might once have filled them.

Despite the footprint-like appearance that drew attention to the images, the Curiosity team does not believe the marks are actual footprints, according to the team. Researchers say the formations instead offer a new clue to the geological processes that have shaped Mount Sharp.

To examine the pits in detail, the Curiosity team used the rover's onboard cameras and instruments, according to a mainstream source. The MAHLI camera and the Mastcam instrument captured overlapping images that can be combined into three-dimensional models of the pits and their surrounding structure, according to NASA mission reporting.

Separately, Mastcam images and measurements from the ChemCam instrument revealed rock layers whose texture and structure changed noticeably over short distances, according to a source describing the findings. Scientists say these variations could point to shifts in the conditions under which the sediments were originally deposited. The rover also examined rough, grey layers that were more resistant to erosion than the surrounding rock, according to an unnamed mainstream report. ChemCam, MAHLI and the Alpha Particle X-ray Spectrometer analyzed the material, which researchers say may have a different chemical composition from the bedrock around it.

Curiosity has been exploring Mars since landing in 2012, and after nearly 14 years on the planet, the rover continues to provide scientists with new insights into its geological history, according to mission framing.