Planetary scientists have proposed a possible explanation for the nature of Venusian phosphine without involving the activity of microorganisms. The emergence of this potential biomarker is assumed to be responsible for plume volcanism, which is still active on Venus.
Phosphine on Venus explained?
1. The return to the question of the potential habitability of Venus occurred last fall when it was announced that phosphine gas was found in its atmosphere at an altitude of about 53-61 kilometers from the planet’s surface, which is considered a potential biomarker for rocky exoplanets.
2. Later, this was indirectly confirmed by the archival data of automatic vehicles, however, the authors of the discovery, after criticizing it during the re-analysis of the data, gave a new, lower estimate of the phosphine content in the clouds of Venus.
3. Moreover, initially, it was stated that the presence of phosphine is difficult to explain using chemical processes in the atmosphere or on the surface of the planet, including volcanism, however, the biological pathway of the formation of this substance as a result of the vital activity of microorganisms is currently poorly understood.
4. Ngoc Truong and Jonathan I. Lunine of Cornell University have published a paper that points to the plausibility of chemical processes associated with volcanism as an abiotic source of Venus phosphine.
5. It is assumed that metal phosphides come from deep layers of the planet’s mantle to its surface during plume volcanic processes, and then enter the atmosphere in the form of dust as a result of explosive eruptions. In the atmosphere, phosphides, being in the aerosol layer, react with sulfuric acid to form phosphine.
6. Scientists have calculated the rate of loss and replenishment of phosphine in the atmosphere of Venus using data from laboratory experiments during various chemical reactions.
7. It turned out that an explosive eruption, like Krakatoa, with an ejection volume of about ten cubic kilometers, would throw enough phosphides to heights of 40-80 kilometers to form phosphine.
8. The ongoing active volcanism on Venus is indicated by episodic bursts of sulfur dioxide in the upper part of the planet’s cloud cover and changes in the amount of haze above the clouds.
9. In addition, the lifetime of phosphine in the most stable layers of the atmosphere of Venus can be much longer than on Earth due to the much lower concentration of OH radicals.
10. The researchers note that their work is so far only an estimate and requires further, larger-scale studies of Venus, both for the search for active volcanoes and for an accurate determination of the phosphine content at different altitudes in the atmosphere of Venus, which should be carried out by orbiters or descent vehicles.
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• Friedlander, B. (2021, July 12). Trace gas phosphine points to volcanic activity on Venus. Cornell Chronicle.
• Starr, M. (n.d.). That Scandalous Phosphine on Venus Really Could Come From Volcanoes, Says New Study. ScienceAlert.
• Truong, N., & Lunine, J. I. (2021, July 20). Volcanically extruded phosphides as an abiotic source of Venusian phosphine. PNAS.