Martian Organic Compounds: Non-Biological Sources Insufficient to Explain Quantity
A recent study indicates that non-biological sources considered by researchers could not fully account for the quantity of organic compounds present in a sample collected on Mars by NASA's Curiosity rover. This finding suggests a potential new angle in the search for life on the Red Planet.
Curiosity Rover's Discovery
In March 2025, scientists reported detecting small amounts of decane, undecane, and dodecane within a rock sample analyzed by Curiosity's chemistry lab. These compounds represented the largest organic molecules identified on Mars to date. Researchers hypothesized they might be fragments of fatty acids preserved in ancient mudstone within Gale Crater. On Earth, fatty acids are predominantly generated by living organisms, although geological processes can also produce them.
Probing the Origin: A Follow-Up Study
The initial Curiosity data did not definitively determine the origin of these molecules as biological or non-biological. This led to a follow-up study aimed at assessing whether known non-biological sources, such as delivery via meteorite impacts, could explain the observed quantities.
The study, published February 4 in the journal Astrobiology, concludes that the considered non-biological sources were insufficient to fully explain the abundance of these organic compounds.
Consequently, researchers state it is reasonable to hypothesize that living organisms could have contributed to their formation.
Reconstructing Ancient Martian Organics
To reach this significant conclusion, scientists utilized a combination of laboratory radiation experiments, mathematical modeling, and Curiosity data. This multi-pronged approach was designed to estimate the original amount of organic material present before an estimated 80 million years of exposure to cosmic radiation on the Martian surface. The calculations suggested a significantly higher initial quantity than typical non-biological processes could produce.
What Comes Next
The research team emphasizes that further investigation is required to more accurately understand the degradation rates of organic molecules in Mars-like rock under Mars-like conditions.
This additional study is considered necessary before definitive conclusions can be drawn regarding the past or present existence of life.