Exogenous organics
Organic carbon delivered to a planetary surface by meteorites, comets, IDPs, or other extraterrestrial sources. Distinct from panspermia (which is about transfer of cells or microbes); exogenous organics is the more conservative claim that prebiotic feedstocks are widely delivered by carbonaceous bodies.
Key evidence
- murchison-meteorite (1969) — amino acids, nucleobases, hexamethylenetetramine.
- ryugu (Hayabusa2 sample return) — DNA-base detections.
- bennu-asteroid — 14 protein-forming amino acids in 2025 Nature Astronomy analysis.
- Mars — Curiosity’s 2026 SAM/TMAH detection of benzothiophene in gale-crater is consistent with interstellar / meteorite-delivered origin (amy-williams); see src-curiosity-mars-life-molecules-2026-04 and src-mars-organics-fresh-clues-2026-04.
In the origin-of-life debate
amy-williams articulates the modern consensus as a combined in-situ + exogenous origin: geological/hydrothermal in-situ chemistry plus meteorite-delivered feedstocks together produce the prebiotic inventory. The same logic is now being applied to early Mars.