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SUMMARY:Heterogenous Chemistry and The Possibility for Life in the Clouds 
 of Venus - Paul Rimmer\, Department of Physics\, University of Cambridge
DTSTART:20230220T143000Z
DTEND:20230220T153000Z
UID:TALK197728@talks.cam.ac.uk
CONTACT:Vichawan (Print) Sakulsupich
DESCRIPTION:The clouds of Venus are believed to be made of sulfuric acid (
 H2SO4)\, water (H2O) and other minor constituents. The chemical inventory 
 in the clouds of Venus is unknown due to conflicting and extraordinary obs
 ervations from several probes that have traveled through the clouds. X-Ray
  diffraction observations indicate that the clouds are formed primarily of
  the elements P\, S\, Cl and Fe\, with roughly equal amounts of S and P. M
 ass spectrometry and chromatography indicate significant amounts of molecu
 lar oxygen (O2)\, methane (CH4)\, ethane (C2H6)\, hydrogen sulfide (H2S)\,
  phosphine (PH3) and ammonia (NH3) in the clouds\, and detect water vapor 
 at more than 1000 times the above-cloud and below-cloud measurements\, and
  more than 100 times the spectroscopic observations of the probes themselv
 es. Depletion of sulfur dioxide (SO2) above the clouds is well-supported b
 y probes\, satellite and ground-based observations\, and cannot be explain
 ed solely by converting SO2 into H2SO4 and elemental sulfur. I will talk a
 bout three hypotheses that can explain the depletion of SO2 and some of th
 e anomalous detections within the clouds: that there are hydroxide salts i
 n the clouds (1)\, that there is life in the clouds converting N2 into NH3
  (2)\, and that iron-sulfur chemistry is taking place in the cloud droplet
 s (3). I will conclude by focusing on the “life in the clouds” hypothe
 sis\, and show that\, if these chemical anomalies are signs of life\, it i
 s very different from terrestrial life\, and its presence would pose a ser
 ious challenge for using disequilibrium biosignatures to search for life o
 n other planets (4).\n\nREFERENCES:\n\n(1) Rimmer\, P.B.\, Jordan\, S.\, C
 onstantinou\, T.\, Woitke\, P.\, Shorttle\, O.\, Hobbs\, R. and Paschodima
 s\, A.\, 2021. Hydroxide salts in the clouds of Venus: Their effect on the
  sulfur cycle and cloud droplet pH. The Planetary Science Journal\, 2(4)\,
  p.133.\n\n(2) Bains\, W.\, Petkowski\, J.J.\, Rimmer\, P.B. and Seager\, 
 S.\, 2021. Production of ammonia makes Venusian clouds habitable and expla
 ins observed cloud-level chemical anomalies. Proceedings of the National A
 cademy of Sciences\, 118(52)\, p.e2110889118.\n\n(3) Jiang\, C.Z.\, Rimmer
 \, P.B.\, Lozano\, G.G.\, Tosca\, N.J.\, Kufner\, C.L.\, Sasselov\, D.D.\,
  Thompson\, S.J. Iron-Sulfur Chemistry Can Explain the Ultraviolet Absorbe
 r in the Clouds of Venus. Submitted to Science Advances.\n\n(4) Jordan\, S
 .\, Shorttle\, O. and Rimmer\, P.B.\, 2022. Proposed energy-metabolisms ca
 nnot explain the atmospheric chemistry of Venus. Nature Communications\, 1
 3(1)\, p.3274.\n\n\n---------------------------------------\n\n\nCAS Union
 Road is inviting you to a scheduled Zoom meeting.\n\nTopic: CAS SEMINAR: P
 rof Paul Rimmer\nTime: Feb 27\, 2023 02:30 PM London\n\nJoin Zoom Meeting\
 nhttps://us02web.zoom.us/j/85726562020?pwd=aDFpWmtpSDZNbFNjS3lPWWdrMmhMUT0
 9\n\n\nMeeting ID: 857 2656 2020\nPasscode: 823668
LOCATION:Chemistry Dept\, Unilever
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