The discovery of samples of long-chain organic molecules on the surface of Mars by the Curiosity rover, revealed at the end of March 2025 by the United States space agency (NASA), moved the scientific community due to the possibility of representing the existence of life in the past of the red planet. At the time, the discovery of the hydrocarbons decane, undecane and dodecane in rocks monitored by the vehicle in the Gale crater was announced. These compounds have 10, 11 and 12 carbon atoms, respectively.
Alvaro Penteado Crósta, a full professor at the Department of Geology and Natural Resources (DGRN) at Unicamp’s Institute of Geosciences (IG), however, recommends caution when speculating about the origin of the material found. “Although it could be indirect evidence of the past existence of life on Mars, it could also be something produced by geological processes, such as the interaction between hydrothermal fluids due to volcanism, a phenomenon that also occurred on the planet,” he explains. “The discovery is undoubtedly fantastic, but for now, it is just one more step in the search for biosignatures,” he says.
Biosignatures represent past evidence of the presence of life in a given place in space, usually consisting of traces of biological activity. In the case of the compounds recently found on Mars, it is not possible to determine who or what created them due to limitations inherent to the Curiosity rover — a mobile laboratory with instruments featuring technology from more than a decade and a half ago that has been in operation on the Red Planet since 2012 — or due to the need to transport the samples for analysis in better-equipped laboratories on Earth.
Watch the video produced by NASA:
The molecules of decane, undecane and dodecane on Mars are relevant because they are compounds generally derived from fatty acids, which would increase the chance that they came from living beings. “In comparison with other materials that had already been identified on Mars, such as methane or chlorobenzene, the possibility is greater, but it is not yet possible to state with certainty that they came from living organisms,” says Crósta.
Confident in the gradual joint effort to unravel the mysteries of Mars, Crósta recalls the importance of another experiment operating on the Martian surface. “Perseverance, for example, focuses on a very different place than Curiosity, as it investigates the delta of a river where sediments have been deposited. This suggests that, at a remote time, there was a lot of water there,” he highlights.
The robot, which has been operating in the Martian crater Jeziro since 2021, has not yet found organic molecules as large as Curiosity's, but it has an advantage over its search partner. "Perseverance collects samples using a probe, placing the material found in sealed tubes, which in turn are left to be brought to Earth as soon as possible," it says. However, transportation is still expected to take some time due to recent cuts of up to 50% in NASA's funding, confirmed in early May by the White House when announcing the proposal United States Budget for 2026.
Caution as an ally
Despite the general public’s expectations, Crósta praises the scientists’ diligence in addressing the issue in the press or other media outlets. “What was discovered cannot be considered in any way a confirmation that there was life on Mars in the past. And, among those who actually study this type of phenomenon, there is no interpretation that they are linked to life. The mistaken speculation, if there is any, does not come from the scientific community,” he states.
The rigor in conducting research has been present since the beginning, when NASA chose the two Martian craters in question for biosignature investigations because they represent possible aquatic environments in the past.
This is known thanks to the work of remote sensors operating from satellites that report the mineralogical and chemical composition of the surface surveyed from a distance — taking advantage of the advantage, compared to Earth, of the absence of an atmosphere on the Martian planet. Crósta believes that, in the future, these sites may offer even more impressive traces of Mars' past.
“There is the possibility of finding something beyond organic compounds: fossils of living beings, such as bacteria. This is the great virtue of Perseverance, this ability to store these rock samples so that we can analyze them here,” he comments.
Participating in a project that seeks evidence of life in the past on Titan, Saturn's largest moon, the researcher contextualizes the incidence of organic compounds in the Solar System. “This satellite has large quantities of this type of material, the atmosphere has organic elements, there is methane rain, there is methane in a liquid state there,” he lists. “Despite all this potential, we still need to be cautious, because all these phenomena may also have been generated by processes unrelated to any living being,” he warns.
The professor also considers, in addition to Mars and the moon Titan, other icy satellites of Jupiter and Saturn as places with potential for research of this nature. “The icy moons of these two giant planets have a lot of water and organic compounds, not to mention the existence of aquatic oceans just below large layers of ice on the surface of the satellites. Oceans with salts and water are exactly the environments in which life began on Earth,” he explains.
NASA is planning to launch the Dragonfly vehicle to travel to Titan starting in 2028, if budget cuts do not affect the agency's schedule. "This mission will have a large helicopter, since this moon has an atmosphere, enabling the flights of this equipment. It is like a vehicle like Perseverance, but one that can fly and glide, carrying a laboratory with several instruments to land in certain locations, such as the surroundings of a large crater," he concludes.
