>>12110597>>12114281>>12114536I propose the following cycle that explains Venusian phosphine formation without mysterious alien life:
1) as temperature rises during the day, phosphoric acid present on Venus decomposes to phosphorus trioxide (detected by Vega probe)
2) phosphorus trioxide evaporates and rises to upper atmosphere, where is precipitates and forms aerosol
3) phosphorus trioxide reacts with water in upper atmosphere, forming phosphorous acid
4) the key step - phosphorous acid precipitates to back to lower atmosphere, dissociates at high temperatures (>200°C) into phosphoric acid and our phosphine
5) phosphine rises up and is eventually also oxidized back to phosphorous acid
6) phosphoric acid precipitates out and deposits into regolith (or simply lower atmosphere) during the night, returning to step 1
This cycle is impossible on Earth because it requires atmospheric temperatures of 200+°C, which are present on Venus
another source of phosphine could be this mechanism - P rich minerals exposed to strong mineral acids combined with mechanical forces, such as tectonic movements release phosphine
https://pubs.acs.org/doi/full/10.1021/es050682wand we know Venus is extremely tectonically active
another minor source of phosphine could be from electric arcs (lightnings)
