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SYSC: Symposium The Sustainability Challenge: A Decade of Transformation

SYSC 1: The Sustainability Challenge: A Decade of Transformation

SYSC 1.5: Hauptvortrag

Montag, 9. März 2026, 17:15–17:45, HSZ/AUDI

Impacts of Cosmic Dust and Space Debris in the Terrestrial Atmosphere — •John Plane — School of Chemistry, University of Leeds, UK

Cosmic dust particles are produced from sublimating comets and collisions between asteroids. Because the particles enter the atmosphere at hypersonic velocities, collisional heating with air molecules leads to vaporization of their metallic constituents. The injection of these elements causes a wide variety of atmospheric phenomena: global layers of metal atoms between 80 and 105 km; airglow emissions; metallic ions (sporadic E layers) which affect radio communications; and meteoric smoke particles which enable the nucleation of mesospheric ice clouds and the freezing of polar stratospheric clouds. Certain metal atoms can be observed by ground-based lidar and from satellites, providing excellent tracers of dynamics and chemistry at the edge of space.

The global mass input rate of cosmic dust to the atmosphere is estimated to be around 27 tonnes per day. This estimate was obtained using an astronomical dust model to provide the size and velocity distributions of dust in the inner solar system, combined with a chemical ablation model to determine the rates of metal injection and deposition of cosmic spherules in the polar ice-caps. The re-entry of spacecraft from low Earth orbit currently produces influxes of metals such as aluminium and lithium which already exceed natural background levels. The atmospheric implications of the expected significant increase in these anthropogenic fluxes during the next decade will be discussed.

Keywords: cosmic dust; space debris; ozone layer; metallic layers; sporadic E layers