Re: Organic carbon detected in Bright Angel rock formation on Mars

"Jim Wilkins"  wrote in message news:[email protected]...

"Amino acids may be structurally chiral, meaning that they have two possible
non-superimposable mirror image structures, termed enantiomers.
Conventionally, these are referred to as left-handed (L) and right-handed
(D) by analogy with glyceraldehyde. Living beings use L-amino acids, "

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This explains and illustrates right and left handed molecules further.
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Chirality/Fundamentals_of_Chirality

The handed molecules shown are amino acids, NH2 is the amino part, COOH the 
acid, R varies between types.

The measurement is optical, requiring a polarized light source, and 
different from the spectral absorption line observation that identifies 
molecules in space by their "color" in infrared light from a more distant 
source, but doesn't indicate biological origin as handedness does.