Abstract

The Earth likely experienced a greater rate of collisions with extraterrestrial matter in early Solar System history than it does today. This is highly relevant for the chemical origins of life, given that many types of extraterrestrial matter are enriched in life-​limiting elements relative to Earth’s crustal rocks. Unpicking this relationship requires us to obtain some constraints on the dynamical evolution of the Solar System (i.e., collision rates between asteroids and between asteroids and Earth), the chemistry of extraterrestrial matter accreted by Earth, and the subsequent processing of that matter on the surface of prebiotic Earth. We have investigated each of these topics, leveraging isotopic analyses of meteorites from asteroids that experienced collisions, geochemical measurements of the fine-​grained cosmic dust particles that those collisions generated, and modelling of extraterrestrial matter processing on the surface of prebiotic Earth. Our combined approach leads us to better understanding of the role and relevance of collisional activity in seeding planets with the elements needed for life, suggesting that cosmic dust in particular represents a viable and flexible planetary fertiliser.