[zipwitch]

Solar wind as the culprit was still being tossed around in 2017.

https://www.nasa.gov/press-release/nasas-maven-reveals-most-... "The new result reveals that solar wind and radiation were responsible for most of the atmospheric loss on Mars, and the depletion was enough to transform the Martian climate."

[ourlordcaffeine]

Ah, maybe I read that geological processes were ruled out rather than being the main driver