NASA scientists were recently “astonished” by an unusual discovery made by the Perseverance rover involving a series of dark gray spheres on Mars, whose origin remains unclear.
The spherical objects were found within an unusual rock discovered by Perseverance at Broom Point, located on the rim of Jezero crater, which the robotic rover has been exploring since it arrived on Mars in February 2021.
Before arriving at the unique location two weeks ago, found on the lower slopes of an area NASA scientists have dubbed Witch Hazel Hill, the Perseverance team had already been aware of the existence of unusual stone formations indicated by an array of light and dark colored bands, the presence of which had been detected using orbital imagery of the region.
Last week, Perseverance scraped a sample from one of the lighter-toned areas, revealing something “very strange” in the underlying rock that left NASA scientists scratching their heads.
The stony sample abraded by the rover’s science instruments revealed the presence of “hundreds of millimeter-sized spheres,” according to an update in a NASA blog post by Imperial College London Ph.D. candidate Alex Jones.
Enigma at St. Paul’s Bay
The rock in question, which the Perseverance team has dubbed “St. Pauls Bay,” was filled with tiny millimeter-sized spheres. The objects, which possess a dark gray coloration that gives them an almost metallic appearance, range in shape from elliptical to perfect spheres. Intriguingly, some of the spherical formations contain tiny pinholes that cause them to look similar to beads.
Some of the millimeter-sized spherules also revealed angular edges, which are believed to be evidence of fracturing that occurred at some point in the past, or even possibly during abrading performed by Perseverance.
“What quirk of geology could produce these strange shapes?” Jones asked in the NASA post.
spheres on Mars
Images of the unusual spheres on Mars obtained by the Perseverance rover’s SuperCam Remote Micro Imager (RMI) on March 11, 2025 (Credit: NASA/JPL-Caltech/LANL/CNES/IRAP).
Imagery of the mysterious spherules was subsequently captured using Perseverance’s SuperCam Remote Micro Imager (RMI) on March 11, 2025, the 1,442nd day of the rover’s participation in NASA’s Mars 2020 mission.
Not the First Time Scientists Have Found Spheres on Mars
Although the odd spherical objects remain an enigma and the Perseverance Science Team is currently “working hard to understand their origin,” this is not the first time unusual spherules have been found on the Red Planet.
In a similar discovery in 2004, Perseverance’s predecessor, the Mars Exploration Rover Opportunity, found small spherical structures that NASA scientists dubbed “Martian Blueberries during explorations at Meridiani Planum.
Similarly, the Curiosity rover has found evidence of rocks containing these enigmatic Martian spherules at Yellowknife Bay within the Gale crater.
Perseverance has also uncovered unusual textures in other samples examined at Jezero crater, including samples from within sedimentary rocks at Neretva Vallis, the crater’s inlet channel.
What Are the Mysterious Spheres on Mars?
Despite their unusual, almost manufactured appearance, the most likely explanation for the spheres is that they are concretions, a geological process in which accumulations of matter form from interaction with groundwater that circulates through porous spaces within surrounding rock.
Hubble
Concretions aren’t the only means by which spherules are formed, however. Under certain conditions, they can also be created when tiny bits of molten rock are rapidly cooled, a process known to occur coinciding with meteorite impacts and volcanic eruptions.
In the case of the Broom Point spheres, discerning which process might have given rise to their formation is key since each possible mechanism would point to very different origins, each with different implications for the ancient history of the surrounding Martian environment.
One potentially important clue Perseverance team scientists are working with involves the origins of St. Pauls Bay, the stone that revealed the unusual spherical structures. Right now, NASA geologists believe the stone is a float rock, which describes something that is not in place (not to be confused with certain types of rock that can actually float on water, such as pumice and other very light, porous stones).
By studying the textures observed in the samples from St. Pauls Bay, the Perseverance team hopes to establish a deeper understanding of the broader stratigraphy at Witch Hazel Hill. Further studies will likely help yield a deeper understanding of this portion of the Martian environment and potentially reveal clues to the origin of Jezero crater’s mystery spherules.
For now, establishing the proper geological context for the spheres will be a crucial factor in determining how they formed, which may ultimately provide additional insights to the Perseverance science team about the geological history of Jezero crater, as well as other locations of interest on the Martian landscape that may provide clues to the presence of liquid water in the Red Planet’s history, and even the possibility that life may have existed there at some time in the past.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email atmicah@thedebrief.org. Follow his work atmicahhanks.comand on X:@MicahHanks.