>>12121746>Energetic events are also not an effective route to making PH3.Lightning may occur on Venus, but at sub-Earth activity levels33.We find that PH3 production by Venusian lightning would fallshort of few-ppb abundance by factors of 10^7 or more. Similarly,there would need to be >200 times as much volcanic activity on Venus as on Earth to inject enough PH3 into the atmosphere (up to~108 times, depending on assumptions about mantle rock chemistry). Orbiter topographical studies have suggested there are notmany large, active, volcanic hotspots on Venus34. Meteoritic delivery adds at most a few tonnes of phosphorus per year (for Earth-like accretion of meteorites). Exotic processes such as large-scale tribochemical (frictional) processes and solar wind protons also onlygenerate PH3 in negligible quantities (W. Bains et al., manuscript in preparation, submitted to Astrobiology as ‘Phosphine on Venus cannot be explained by conventional processes'; also see ExtendedData Fig. 10)
