Astronomy: Challenges in the search for life on Mars | Nature Communication | Nature Portfolio

Paper drawing attention to the fact that scientific instruments currently used on Mars may not be sensitive enough to detect possible traces of life in the Martian environment.Nature Communicationis published in

There have been several attempts to search for signs of life on Mars since the Viking program in the 1970s. Half a century later, even the most sophisticated instruments on the Mars Rovers NASA Curiosity and Perseverance have identified only a few simple organic molecules. These results raise questions about whether the limitations of current instruments and the nature of the material in Martian rocks could prevent sufficient evidence of life from being detected.

Armando Azua-Bustos and his colleagues analyzed samples collected from the redstone of the river delta in the Atacama Desert in Chile, which is currently being used on Mars with experimental equipment of the grade foremost tools that can be used. This deposit formed under very arid conditions about 160-100 million years ago and is currently being investigated using Persistence in the Jezero Crater on Mars and similar geology. In this study, sensitive laboratory techniques were used to detect a mixture of microbial biosignatures (extinct and dead). After culturing and sequencing the microbes, much of the decoded DNA sequence came from an unknown “dark microbiome”, with much of the genetic material never reported before. It was found to be of microbial origin. In contrast, analyzes using testbed instruments used on Mars have detected molecular signatures of microbial fossils at marginal detection limits.

If life existed on Mars billions of years ago, organic matter would be expected to be as small, if not impossible to detect with the techniques currently used on Mars, as the findings of this study show. Azua-Bustos et al emphasize the importance of bringing samples collected on Mars back to Earth to definitively determine whether life has ever existed on Mars.

doi: 10.1038/s41467-023-36172-1

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