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NASA's Perseverance rover finds preserved organic matter on Mars (gizmodo.com)

submitted 1 year ago by FlyingSquid@mander.xyz to c/astronomy@mander.xyz

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Note: Organic matter does not mean life. It is a precursor to life. It does make the possibility of life on ancient Mars more likely.

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[–] TauZero@mander.xyz 7 points 1 year ago (1 children)

Chemists: If it contains carbon it's organic

Anyway, here's the Nature paper:
https://doi.org/10.1038/s41586-023-06143-z

And here's the table listing the actual organic molecules detected:
https://www.nature.com/articles/s41586-023-06143-z/tables/3
Including benzene and naphthalene, and amine acids lysine, tyrosine, phenylalanine, histidine, etc.

Curiously, only L-amino acids were detected. Did they test for D-aa and didn't see any, or did they test for L-aa only? The paper doesn't say. If the former, that's a pretty big deal. As far as I know there is no inorganic process that can produce non-racemic chiral molecules.

[–] TauZero@mander.xyz 3 points 1 year ago

Ah! This reference paper goes into more detail about how the reference spectra for the Raman fluorescence were acquired: https://doi.org/10.1089/ast.2022.0023 They built a fluorescence spectrometer identical to the SHERLOC tool onboard the Perseverance rover on Mars and tested it against a library of molecules of interest, including all L-amino acids and a few of the D-amino acids. Turns out the spectrometer cannot differentiate between the two:

The fluorescence spectra of d-phenylalanine and l-phenylalanine were almost identical, showing no obvious dependence on the chirality of the α-carbon.

Raman fluorescence spectra of 20 amino acids