What does the organic molecule discovery on Mars suggest?
- Gyan Prakash Satyam
- Apr 23
- 2 min read
The quest to find organic molecules on Mars has significantly advanced over the last ten years, with the identification of basic aromatic compounds, S-heterocycles, and aliphatic organic substances in the Gale crater. The in situ identification of more than 20 organic compounds from clay-containing sandstones found in the approximately 3.5-billion-year-old Knockfarrill Hill member of Glen Torridon, located within Gale crater. This was achieved using the Sample Analysis at Mars instrument suite aboard the Curiosity rover. These compounds were extracted during the onboard wet-chemistry procedure using tetramethylammonium hydroxide. Various thermochemolysis by-products, such as benzothiophene, methyl benzoate, and both single- and double-ring aromatic compounds, were produced and identified by evolved gas analysis and gas chromatography-mass spectrometry. The findings demonstrate that the experiment effectively liberated molecules preserved in ancient macromolecular structures or in free organic matter within Martian bedrock, even after approximately 3.5 billion years of geological changes and radiation exposure.
What scientific methodology suggests the organic origin of these molecules
Following extensive research, findings reported in Nature Communications indicate that this represents the most chemically varied organic specimen ever found on Mars. The SAM instrument suite utilised Evolved Gas Analysis (EGA) alongside Gas Chromatography–Mass Spectrometry (GC-MS) to identify more than 20 carbon-based substances, seven of which had not been previously identified on Mars — neither on its surface nor in Martian meteorites. Additionally, EGA results recorded high-molecular-weight signals at mass-to-charge ratios reaching m/z 537, suggesting that the detected fragments are decomposition products of even larger macromolecular organic entities that have been preserved within the ancient rock. This interpretation suggests that this organic molecule discovery on Mars to be of biological origin rather than geological.
What about Martian chemistry
The examination revealed more than 20 organic compounds, with seven of them being previously unrecorded on Mars.
• Initial Nitrogen Heterocycle: Researchers observed a potential nitrogen-containing heterocycle, probably dimethyl-indole. This is regarded as a significant finding since such forms serve as essential building blocks for more intricate compounds like RNA and DNA.
• Aromatic and Sulfur-Containing Substances: For the first time, scientists validated the existence of benzothiophene, a molecule comprising carbon and sulfur typically associated with meteorites. Additional newly recognised molecules comprise naphthalene, methyl benzoate, trimethylbenzene, and tetramethylbenzene.
• Macromolecular Carbon: The identification of these 1-2 ring aromatic structures implies they were released from a vast, ancient macromolecular entity that has remained intact in Martian bedrock for about 3.5 billion years.
How will these findings influence future missions to Titan and Mars?
The recent findings from Curiosity’s Sample Analysis at Mars (SAM) instrument are expected to significantly influence future exploration by providing critical technical and scientific insights for missions to both Mars and Titan.
Future Missions and Instruments
The knowledge gained from Curiosity's first tetramethylammonium hydroxide (TMAH) experiment will directly benefit the following:
Rosalind Franklin Mars Rover (ESA): This mission features the Mars Organic Molecule Analyser (MOMA) instrument., NASA has provided several components for MOMA, including its mass spectrometer, and the instrument is designed to perform wet chemistry using the same TMAH solvent used by Curiosity.
Dragonfly Mission (NASA): This rotorcraft mission to Saturn's moon Titan will carry the Dragonfly Mass Spectrometer (DrAMS)., Like MOMA, DrAMS is also planned to utilise TMAH thermochemolysis to analyse samples.,
Comments