Curiosity Rover Finds Mysterious Pits on Mars That Look Like Footprints — But Aren't
Scientists say the broad, shallow voids in Martian bedrock are 'unlike quite anything we have seen in the past' — and they don't yet know how they formed.
They look uncannily like footprints pressed into wet sand — but NASA scientists are quick to say that is where the resemblance ends. Images captured by the Curiosity rover on Mars' Mount Sharp show a cluster of broad, shallow pits in the bedrock that the mission team describes as 'features unlike quite anything we have seen in the past.' No one yet knows how they got there.
The pits were spotted during recent observations and studied using several of Curiosity's instruments: the Mars Hand Lens Imager (MAHLI), the Mastcam camera, ChemCam (the Chemistry and Camera complex), and the Alpha Particle X-Ray Spectrometer (APXS). The team acquired stereo mosaics and tightly overlapping image sets that can be converted into a digital elevation model of the features, according to Space.com.
Pits are not uncommon — when resistant nodules or pebbles weather out of their host rock, they leave behind a void. But the pits of this week were much broader and shallower than past features and were not accompanied by obvious objects that were once in the pits.— Michelle Minitti, Deputy Principal Investigator, Curiosity's Mars Hand Lens Imager (MAHLI)
That absence of any remnant material inside the pits is what sets them apart. Typical surface pits on Mars form when a nodule or pebble erodes out of surrounding rock, leaving a void shaped by whatever was once there. These pits have no such obvious explanation — and their unusual width and shallowness make them harder to fit into known geological categories.
Early chemical analysis has added another layer of intrigue. According to Space.com, the team found interesting layers in the pit material that appear chemically different from the main bedrock. What that difference means for the pits' origin or age is not yet clear.
They were a welcome new puzzle into the processes that have affected this particular section of rocks in the stratigraphy of Mount Sharp.— Michelle Minitti, Deputy Principal Investigator, Curiosity's Mars Hand Lens Imager (MAHLI)
The discovery comes as Curiosity marked a milestone: its 5,000th Martian day, or sol, on Mars. To mark the occasion, NASA released a color-tinted 'postcard' panorama captured by the rover's black-and-white navigation cameras while it was parked at a sand ridge nicknamed 'Chocolatal.' The first image was taken on Aug. 30, 2026, at 9:56 a.m. local Mars time; the second on Sep. 2, 2026, at 5:39 p.m. — the 5,000th and 5,003rd sols of the mission respectively. The two images were merged and given an artistic color treatment, with blue representing the morning panorama and yellow the afternoon.
The postcard shows Curiosity's own deck in the foreground — including its UHF antenna and its finned Multi-Mission Radioisotope Thermoelectric Generator, a nuclear power source — with the rover's tracks trailing off into the distance. Curiosity is currently in the lower foothills of Mount Sharp, a 3-mile-tall (5-kilometer-tall) mountain inside Gale Crater. The crater rim is just barely visible on the horizon.
The 'footprint' framing, while eye-catching, is geological rather than biological. Curiosity has a history of photographing features that spark public imagination: a 'jellyfish' in one image turned out to be a camera artifact caused by a cosmic ray striking the sensor; rocks resembling coral and 'dragon scale' formations in a crater named Antofagasta have also drawn attention. In each case, natural processes provided the explanation. The new pits are expected to follow the same pattern — but scientists say they need more analysis before they can say what that explanation is.
Curiosity landed on Mars in 2012 and has been operating for 14 years. It was built by NASA's Jet Propulsion Laboratory, managed by Caltech in Pasadena, California. JPL leads the mission on behalf of NASA's Science Mission Directorate as part of the Mars Exploration Program.
Why it matters — Curiosity continues to find geological features on Mars that don't fit existing categories, and each unexplained formation adds a piece to the puzzle of how the planet's surface formed and changed over time.
⚠ Not yet confirmed
- The pit material is chemically different from the surrounding main bedrock.
- The 'jellyfish' seen in a separate Curiosity image was caused by a cosmic ray striking the camera sensor.
Reported by nasa.gov, petapixel.com, space.com, dailygalaxy.com, universetoday.com
