The cometary delivery of prebiotic feedstock molecules to the early Earth and rocky exoplanets - Richard Anslow
When: Friday, October 17, 2025, 2:30 PM - 3:30 PM
Where: G. O. Jones, Room 610, Mile End
Speaker: Richard Anslow (Institute of Astronomy, University of Cambridge)
Title: The cometary delivery of prebiotic feedstock molecules to the early Earth and rocky exoplanets
Abstract:
An early period of cometary bombardment has long been speculated to be an important source of prebiotic feedstock molecules, required for the origins of life on Earth. In support of this interpretation, comets boast a rich diversity of volatile organic molecules, with many thought to be limiting for prebiotic chemistry. Modelling studies suggest, however, that a significant proportion of these fragile organic molecules will be destroyed during hypervelocity impact with Earth. In this talk I will discuss recent work reassessing the ability of comets to deliver these key feedstock molecules to Earth, leveraging recent advances in cometary impact simulations, comet-atmosphere interactions, and the dynamical modelling of short-period comets' origin and evolution. Taken together, the rapid decline in Earth's cometary impact bombardment and the efficient destruction of fragile cometary organics indicate that the successful delivery of prebiotic feedstock molecules was an exceedingly rare event, challenging the long-held hypothesis that cometary impacts played an important role in the origins of life on Earth. I will finish by discussing the prospects for cometary delivery to rocky exoplanets, demonstrating that planetary system architecture and stellar mass play an important role in controlling the impact velocity distribution of comets, and the corresponding survival of prebiotic feedstock molecules.