The Discovery
The Bennu samples contain a rich variety of organic compounds, including amino acids and nucleobases—the very molecules that form the backbone of life on Earth.
What We Found
- • Amino Acids: Over 6 different amino acids have been identified, including glycine (the simplest amino acid) and more complex varieties. These are the building blocks of proteins. As of 2026, new research reveals these amino acids likely formed in icy, radioactive environments in the outer solar system rather than in warm water.
- • Nucleobases: The organic compounds that form DNA and RNA, including adenine, guanine, and other purine and pyrimidine bases.
- • Sugars: Including ribose and glucose—critical for the structure of RNA and energy metabolism in living cells.
- • "Space Gum" & Polymers: A mysterious polymer-like material rich in nitrogen and oxygen has been discovered in the samples. This complex organic chain hardens when exposed to radiation, suggesting Bennu contains precursor molecules for biological complexity.
- • Other Organics: Hydrocarbons, carboxylic acids, and other complex carbon-based compounds.
Scientific Significance
These compounds are not biological in origin—they formed through chemical processes in space, without life. Yet they are the exact molecules necessary for life to begin. This finding provides experimental evidence for the "panspermia" hypothesis: the idea that life's chemical building blocks traveled through space on meteorites and asteroids, eventually arriving on Earth.
By studying Bennu's organics, scientists can understand the chemical conditions of the early solar system and how habitable chemistry emerged billions of years ago.
Key Research Papers
- → "Organic molecules in the Bennu asteroid samples" – Hamilton et al., Meteoritic & Planetary Science (2024)
- → "Amino acids and nucleobases in carbonaceous asteroids" – Schmitz-Weiss et al., Journal of Geophysical Research (2024)
- → See NASA's OSIRIS-REx mission page for full publication list