Comets Unlikely Sources of Life’s Building Blocks

Computer simulations (100,000 runs) using modern comet‑formation and impact models find that typical comet impact velocities and energies on early Earth would have destroyed fragile organics like hydrogen cyanide, making direct delivery of intact prebiotic molecules by comets improbable. The study notes asteroid samples (Bennu, Ryugu) and lower‑velocity comet impacts on smaller bodies like ancient Mars as more plausible extraterrestrial contributions to prebiotic chemistry. — If comets are poor carriers of intact prebiotic molecules, origin‑of‑life research priorities and planetary exploration strategies (funding for sample returns, Mars vs comet missions) may shift toward slower impactors and in‑situ environments.