Phosphine Gas in the Cloud Decks of Venus
Abstract
Measurements of trace-gases in planetary atmospheres help us explore chemical conditions different to those on Earth. Our nearest neighbor, Venus, has cloud decks that are temperate but hyper-acidic. We report the apparent presence of phosphine (PH3) gas in Venusian atmosphere, where any phosphorus should be in oxidized forms. Single-line millimeter-waveband spectral detections (quality up to ~15 sigma) from the JCMT and ALMA telescopes have no other plausible identification. Atmospheric PH3 at ~20 parts-per-billion abundance is inferred. The presence of phosphine is unexplained after exhaustive study of steady-state chemistry and photochemical pathways, with no currently-known abiotic production routes in Venusian atmosphere, clouds, surface and subsurface, or from lightning, volcanic or meteoritic delivery. Phosphine could originate from unknown photochemistry or geochemistry, or, by analogy with biological production of phosphine on Earth, from the presence of life. Other PH3 spectral features should be sought, while in-situ cloud and surface sampling could examine sources of this gas.
Cite
@article{arxiv.2009.06593,
title = {Phosphine Gas in the Cloud Decks of Venus},
author = {Jane S. Greaves and Anita M. S. Richards and William Bains and Paul B. Rimmer and Hideo Sagawa and David L. Clements and Sara Seager and Janusz J. Petkowski and Clara Sousa-Silva and Sukrit Ranjan and Emily Drabek-Maunder and Helen J. Fraser and Annabel Cartwright and Ingo Mueller-Wodarg and Zhuchang Zhan and Per Friberg and Iain Coulson and E'lisa Lee and Jim Hoge},
journal= {arXiv preprint arXiv:2009.06593},
year = {2021}
}