NASA's Perseverance rover has found possible traces of microbiological life on Mars, but an analysis on Earth would be needed for a conclusive judgment on the origins of the substances in question. This has been made public by several research institutions, but the scope of the announcement is usually limited. Imperial College London, for example, writes that the geological formations in question "could be a convincing potential biosignature," while the acting head of NASA, Sean Duffy, speaks of the greatest success to date in the search for life on Mars. However, the researchers point out that the substances in question could also be formed abiotically.
The substances were found at a formation called "Bright Angel," where Perseverance was traveling in the early summer of 2024. It was assumed to be a former riverbed, but analyses of the subsurface had revealed minerals that would have been quickly washed away. The remains at the bottom of the former river would therefore have indicated an older lake. "This is exactly the kind of life-friendly environment we were looking for on this mission," explains Alex Jones from Imperial College London, who was involved in the discovery. As a result, the composition of the rock there was examined more closely, he continues.
Chemical analyses of the remains of the former mud then revealed millimeter-sized structures containing a lot of iron phosphate and iron sulphide, the team writes. These appear to have been formed during chemical reactions in which organic carbon was involved. This process could have been driven by abiotic but also biological chemistry; on Earth, they would be associated with microbiological life, writes Imperial College London. At the same time, the combination of chemical compounds found in "Bright Angel" could be "a rich source of energy for microbial metabolic processes," adds study leader Joel Hurowitz from Stony Brook University in New York.
"Astrobiological discoveries, especially those related to the potential discovery of past extraterrestrial life, require extraterrestrial evidence," Katie Stack Morgan, from NASA, categorizes the discovery. Getting it into a peer-reviewed scientific publication is a crucial step. She also points out that the traces found could also be the result of non-biological processes, but this would require environmental conditions for which no evidence has been discovered. It is also unknown whether these processes can even take place at the low temperatures that exist on Mars.