What it is
Analysis of the OSIRIS-REx samples returned from asteroid Bennu, kept free of Earthly contamination, found the rock rich in carbon, nitrogen and ammonia. The team detected 14 of the 20 amino acids used in terrestrial biology, all five of the nucleobases that make up DNA and RNA, and roughly 10,000 distinct nitrogen-bearing chemical species. Nitrogen-15 enrichments indicate these molecules formed in a cold molecular cloud or the outer protoplanetary disk.
Why it matters
This is the most complete catalog of life's chemical building blocks ever assembled from an uncontaminated extraterrestrial sample, showing that all five genetic bases and much of the amino-acid alphabet were present in the early solar system. Because the samples never touched the biosphere, the 10,000 nitrogen-bearing compounds can be read as genuine records of prebiotic chemistry rather than terrestrial contamination.
Underlined numbers link to their source. Every metric and quoted figure is listed under Sources and data below.
Filed underastrochemistry, OSIRIS-REx, Bennu, origin of life, amino acids