An international team of researchers has found ‘phosphine’ – a
rare molecule in the atmosphere of Venus. This gas is very rare and is made
only industrially or by microbes that thrive in the oxygen-free environment.
When Venus was studied using James Clerk Maxwell Telescope (JCMT) in Hawaii and
Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and its spectrum
was analyzed, it was found that Phosphine exists in small amounts on Venus
clouds (twenty molecules in every billion). The researchers first thought this
could be due to activities on Venus surface like volcanic eruptions, lightning,
etc but these couldn’t make such an amount of phosphine on the atmosphere of
Venus. Thus they concluded that the amount of phosphine produced can be mainly
because of microbial action as each bacteria take up phosphate from
minerals, add hydrogen, and gives out phosphine. But the major
question here is how these microbes can survive in the atmosphere of Venus
which is highly acidic (almost 90% sulphuric acid). Most microbes on the
surface of Earth can maximum live up to 5 % acidic environment. Thus confirming
the presence of life on Venus requires more detailed work. If we could show
that life exists in Venus, then the presence of Phosphine in the atmosphere of
the planet could be biosignatures for the existence of life.!
Reference
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Clara Sousa-Silva, Sukrit Ranjan, Emily Drabek-Maunder, Helen J. Fraser,
Annabel Cartwright, Ingo Mueller-Wodarg, Zhuchang Zhan, Per Friberg, Iain
Coulson, E’lisa Lee, Jim Hoge. Phosphine gas in the cloud decks of
Venus. Nature Astronomy, Sept. 14, 2020; DOI: 10.1038/s41550-020-1174-4
Sara Seager, Janusz J. Petkowski, Peter Gao, William Bains,
Noelle C. Bryan, Sukrit Ranjan, Jane Greaves. The Venusian Lower
Atmosphere Haze as a Depot for Desiccated Microbial Life: A Proposed Life Cycle
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2020; DOI: 10.1089/ast.2020.2244
Clara Sousa-Silva, Sara Seager, Sukrit Ranjan, Janusz Jurand
Petkowski, Zhuchang Zhan, Renyu Hu, William Bains. Phosphine as a
Biosignature Gas in Exoplanet Atmospheres. Astrobiology, 2020;
20 (2): 235 DOI: 10.1089/ast.2018.1954
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