A blast of radiation on frozen salts produces the exact signature of carbon dioxide found on Jupiter's moon Europa.
Carbon dioxide on a frozen moon should normally be unstable and disappear into space over time. This experiment showed that electron irradiation of carbonate salts in a cryogenic vacuum generates and traps new CO2. The resulting spectral signatures are a perfect match for the data sent back from Europa. This provides a direct chemical link between the geology of the moon and the intense radiation environment of Jupiter. It explains why a moon that should be chemically dead is actually producing its own atmosphere.
Formation and Trapping of CO2 from Cryogenic Irradiation of Carbonate
arXiv · 2604.27177
The detection of CO2 on the Jovian satellite Europa by Galileo NIMS and recent mapping of the leading side by JWST has revealed that it is most concentrated in geologically young terrains, and its v3 asymmetric stretch appears as a spectral doublet centered at 4.25 and 4.27 um. Since crystalline CO2 is unstable at Europan surface conditions, this observation implies an active source and a trapping medium, which may be separate. To this end, several hypotheses have been proposed, but no laborator