Researchers at Tohoku University have developed a detailed model that suggests the organic matter found on Mars may have been formed from atmospheric formaldehyde, providing new insights into the potential for past life on the red planet.
Deciphering Puzzling Carbon Isotope Signatures
Scientists have long been stumped by the strange carbon isotopic ratios in the organic matter that Curiosity has sniffed out on Mars. The nature of the organic matter was a telling hint, but not more than that as it could explain only part of the variability in carbon isotope ratios between samples.
Researchers at Tohoku University have now developed a detailed model that provides a strong explanation of this enigma. The data is consistent with a model where 13C loss from Martian organic indicates photodissociation of CO2 by solar UV. This process selectively removes the lighter carbon isotope (12C), which decreases the 13C fractionation.
Some space rocks that landed here on Earth may have carried small traces of organic material from Mars, or worse, formaldehyde!
What is even more interesting is that the researchers decided to concentrate on formaldehyde (H2CO) in their model. Formaldehyde is a relatively simple organic compound that can be used to form more complex organic molecules—like sugars, the building blocks of life as we know it.
The researchers put together a photochemical model and a climate model to calculate how the carbon isotope ratios of formaldehyde on Mars may have evolved in time, going back as far as 3 or 4 billion years. The researchers conclude that formaldehyde may also have been a major driver of the synthesis of complex organic molecules on Mars.
This finding lends a tantalizing clue that bio-essential molecules (sugars and ribose— used in RNA) could have been synthesized on the ancient Mars providing life supporting molecules.
Conclusion
This detailed model constructed by researchers at Tohoku University offers a possible explanation to the puzzling carbon isotope ratios in organic matter on Mars. The identification of a mechanism that would link the process of making formaldehyde with depletion in the heavier carbon isotope in ancient Martian air provides a new view into life potential by this martian atmosphere historian. The research is a critical point in our understanding of the conditions on Mars and the chemical processes that could have led to life on Mars.
