Caveats to Exogenous Organic Delivery

Document Type


Publication Date



A common hypothesis in prebiotic chemistry states that organics were delivered to Earth by meteoric sources. This study investigates that hypothesis by measuring how the transfer of organic matter to the surface of Earth is affected by ablation. Exogenous delivery has been relied upon as a source of primordial material, but it must stand to reason that other avenues (i.e., hydrothermal vents, electric discharge) played a more prominent role in the formation of life as we know it on Earth if exogenous material was unable to deliver significant quantities of organics. For this study, we use a numerical model that considers various properties of meteors such as angle of entry, initial velocity and mass of the object, and atmospheric composition to see how meteors with different initial velocities and masses ablate. Three distinct atmospheric conditions were used to study how meteors ablate in different environments: a modern day atmosphere, a thick carbon dioxide atmosphere, and a thin nitrogen atmosphere. We find that large meteors do not slow down fast enough and impact the surface, annihilating any sources of organics potentially found on the object. Fast meteors with low masses are vaporized during atmospheric entry, and meteors with low velocities and high initial masses impact the surface. Meteors that are about 1 mm are subjected to extensive thermal heating, potentially destroying essential organics. For those objects that survive the atmospheric entry process and reach the surface, 90-99% of the mass is lost by ablation. These conclusions offer several caveats to extraterrestrial delivery models and show that meteors likely did not supply as much prebiotic material as an effective endogenous production route.

Was this content written or created while at USF?


Citation / Publisher Attribution

Presented at the AGU Fall Meeting on December 13, 2018 in Wahington, D.C.