BACKGROUND. The ongoing story of the reported detection of phosphine (PH3) on Venus is an excellent example of how science works and how media coverage may or may not reflect the current consensus on a controversy. On this page I am documenting both the media coverage and the chronology of various publications that address the subject. I am including preprints along with peer-reviewed publications in the chronology because the release of preprints is an important aspect of how this story is evolving.
The astrochemists who have weighed in on both sides of the controversy are respectable professionals. As a group, we are more collegial than combative. Unlike some subfields of science, there are no entrenched camps with ongoing warfare between their agendas. But a big part of all science is the drive to get things right and to be the first to make a discovery or to establish a new perspective on something. Conclusively demonstrating that life exists on Venus would be game-changing, especially since Venus is one of the last places one would expect to find life because the conditions on its surface are brutal.
It is important to note that there are two intertwined controversies associated with this story. (1) Is phosphine present on Venus? (2) If it's present, is its origin biotic (associated with life) or abiotic? The authors of the initial report (Greaves et al.) have argued for a biological origin from day one. A widely-accepted detection of phosphine on Venus would likely be deemed to be much less significant if it was conclusively shown to be abiotic in origin. (Phosphine has been known to be present on Jupiter and Saturn since the late 1970s; no one has suggested it has a biological origin.)
I am including some personal comments (in light green) about my take on various things. These comments are not intended to represent any kind of consensus of the field.

Most of the stories that appear in the media are responses to particular publications that will appear below. I distinguish between ARTICLES by independent journalists and PRESS RELEASES issued by the institution associated with one or more of the co-authors of a publication. There may or may not be greater bias in favor of the co-authors with a press release. One can partially assess potential bias by noting if an article quotes only the authors of a publication or if indpendent experts not associated with the publication are also cited.
14 Sep 2020 Phosphine on Venus; unpacking the Venusian discovery
(article by Chris Gebhardt at nasaspaceflight.com)
Quotes Greaves et al., includes background evidently based on dialog with Jane Greaves.
(This is one of two articles I cited when the news broke.)
14 Sep 2020 Venus Might Host Life, New Discovery Suggests
(article by Adam Mann at scientificamerican.com)
Extensive quotes from Michael Wong, Sanjay Limaye, Jane Greaves, Clara Sousa-Silva, David Grinspoon, and Bruno Bézard.
15 Sep 2020 Venus phosphine find: Unexplained gas hints at potential for alien life
(article by Eric Mack & Jackson Ryan at cnet.com)
Quotes Greaves et al.; includes independent quotes from Brendan Burns, David Grinspoon, Stephen R. Kane, and Kevin McGouldrick.
(This is one of two articles I cited when the news broke.)
21 Sep 2020 PH3 detected on Venus
(article by Ariana Remmel at C&E News)
Quotes Anthony Remijan and Dirk Schulze-Makuch.
02 Oct 2020 Life on Venus? Scientists hunt for the truth
(article by Jonathan O'Callaghan at nature.com)
Cites Greaves et al.; quotes Leonardo Testi, Clara Sousa-Silva, Matthew Pasek, Jason Dittmann, Nour Raouafi, Takehiko Satoh, Jörn Helbert, Sanjay Limaye, and Sue Smrekar.
22 Oct 2020 Venus Is Dead! New Analysis Shows Phosphine, A Possible Biosignature, Is Absent
(article by Ethan Siegel, PhD at forbes.com)
Quotes Snellen et al.; does not include independent quotes.
(This is a fairly detailed article by a professional astrophysicist and science communicator that does justice to the scientific issues.)
29 Oct 2020 Astronomers Hit the Brakes on Claim That Venus's Atmosphere Has Excess Phosphine
(article by The Wire Staff at thewire.in)
Quotes Clara Sousa-Silva.
06 Nov 2020 Controversy erupts among astronomers over whether phosphine really was discovered on Venus
(article by Keith Cooper at physicsworld.com)
Quotes authors of two rebuttal papers, Mark Thompson and Ignas Snellen.
(This article describes the aggressive responses of the IAU and Villanueva et al. to Greaves et al.)
17 Nov 2020 Prospects for life on Venus fade - but aren't dead yet
(article by Alexandra Witze at nature.com)
Cites Greaves et al., Villanueva et al., and Mogul et al.; quotes Sanjay Limaye, Bob Grimm, Jane Greaves, Rakesh Mogul, and David Grinspoon.
21 Dec 2021 New data challenged our understanding of planetary atmospheres
(article by Sam Lemonick at C&E News)
Quotes Sarah Rugheimer and notes comments by Clara Sousa-Silva.
27 Jan 2021 Purported phosphine on Venus more likely to be ordinary sulfur dioxide, new study shows
(press release by James Urton from University of Washington)
Quotes co-authors Victoria Meadows, Andrew Lincowski, and Alex Akins; includes no independent quotes.
28 Jan 2021 Life on Venus claim faces strongest challenge yet
(article by Alexandra Witze at nature.com)
Cites Snellen et al., Akins et al., and Lincowski et al.; quotes Victoria Meadows, Ignas Snellen, and Alex Akins.
04 Feb 2021 'Signs of life' on Venus might just be ordinary sulfur gas
(article by Tom Metcalfe at nbcnews.com)
Quotes Victoria Meadows and Ignas Snellen.
(This article accurately states that Snellen "was not involved with the latest studies"—the two papers by Lincowski and co-authors—but he did author one of the "no phosphine" papers that appeared previously. So his assessment that "... the story of phosphine and possible life on Venus stops here" may be premature.)
29 Jun 2021 Clouds of Venus 'simply too dry' to support life
(article by Jonathan Amos at bbc.com)
Quotes co-authors John Hallsworth and Chris McKay., includes comments by Jane Greaves.
19 Jul 2020 Volcanic Activity on Venus Could Explain Phosphine
(article by Scott Alan Johnston at universetoday.com)
No quotes; mentions Truong & Lunine, Greaves et al. and other studies.

This chronology is based on the first time a peer-reviewed paper was available publicly, not on its formal publication date. As much as possible, this will be based upon when a publication was first released as a preprint on the astrophysics (astro-ph) section of the arXiv server. These preprints are often only posted after the publication has undergone full peer-review and been formally accepted by the journal. Sometimes, however, preprints are posted for manuscripts that have been submitted but not yet reviewed. The article titles are linked to the journal web page via its DOI code. If present, the code under the principle date for the article links to its arXiv preprint page. If a preprint was not posted to arXiv, the date given is either when the paper was accepted or when it was published online, as noted.
14 Sep 2020
The Venusian Lower Atmosphere Haze as a Depot for Desiccated Microbial Life: A Proposed Life Cycle for Persistence of the Venusian Aerial Biosphere. S. Seager, J. J. Petkowski, P. Gao, W. Bains, N. C. Bryan, S. Ranjan, and J. Greaves (accepted for publication in Astrobiology on 13 Aug 2020).
(One of two preprints released just before Greaves et al. was released on 14 Sep 2020. The article was accepted a full month prior to that date; it is apparently awaiting publication in a special collection of articles about Venusian astrobiology.)
14 Sep 2020
Phosphine on Venus Cannot be Explained by Conventional Processes. W. Bains, J. J. Petkowski, S. Seager, S. Ranjan, C. Sousa-Silva, P. B. Rimmer, Z. Zhan, J. S. Greaves, and A. M. S. Richards (accepted for publication in Astrobiology.)
(The other preprint released just before Greaves et al. was released on 14 Sep 2020. No DOI has been assigned as of 19 Jul 2021. As the authors note: "v2 is in press in Astrobiology, Special Collection: Venus; v2 also expands on the potential of phosphides from the deep mantle volcanism as a source of PH3 (as suggested by Truong and Lunine 2021) and shows the volcanic source of PH3 to be unlikely." (See Truong & Lunine 2021 below.)
14 Sep 2020
Phosphine gas in the cloud decks of Venus. J. S. Greaves, A. M. S. Richards, W. Bains, P. B. Rimmer, H. Sagawa, D. L. Clements, S. Seager, J. J. Petkowski, C. Sousa-Silva, S. Ranjan, E. Drabek-Maunder, H. J. Fraser, A. Cartwright, I. Mueller-Wodarg, Z. Zhan, P. Friberg, I. Coulson, E. Lee, and J. Hoge. Nature Astronomy 5, 655-664 (Jul 2021).
(This is the central publication, Greaves et al. The elapsed time of 10 months between the release of the preprint at arXiv and at Nature Astronomy is extraordinary and reflects the degree to which the initial report was subjected to immediate scrutiny and counterclaims. The July 2021 issue of Nature Astronomy also includes a rebuttal paper by Villanuevo et al., a response by Greaves et al. and an as an addendum to their original manuscript, and also a paper by Hallsworth et al. that is evidently a rebuttal to the claim of a biotic origin for phosphine on Venus. See below.)
27 Sep 2020
Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds. R. Mogul, S. S. Limaye, M. J. Way, and J. A. Cordova. Geophysical Research Letters 48, e2020GL091327 (16 Apr 2021).
(Early version of preprint was entitled "Is Phosphine in the Mass Spectra from Venus's Clouds?")
15 Oct 2020
A stringent upper limit of the PH3 abundance at the cloud top of Venus. T. Encrenaz, T. K. Greathouse, E. Marcq, T. Widemann, B. Bézard, T. Fouchet, R. Giles, H. Sagawa, J. Greaves, and C. Sousa-Silva. Astronomy & Astrophysics 643, L5 (Nov 2020).
19 Oct 2020
Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine. I. A. G. Snellen, L. Guzman-Ramirez, M. R. Hogerheijde, A. P. S. Hygate, and F. F. S. van der Tak. Astronomy & Astrophysics 644, K2 (Dec 2020).
27 Oct 2020
No phosphine in the atmosphere of Venus. G. Villanueva, M. Cordiner, P. Irwin, I. de Pater, B. Butler, M. Gurwell, S. Milam, C. Nixon, S. Luszcz-Cook, C. Wilson, V. Kofman, G. Liuzzi, S. Faggi, T. Fauchez, M. Lippi, R. Cosentino, A. Thelen, A. Moullet, P. Hartogh, E. Molter, S. Charnley, G. Arney, A. Mandell, N. Biver, A. Vandaele, K. de Kleer, and R. Kopparapu. Nature Astronomy 5, 631-635 (Jul 2021)
(Rebuttal published with Greaves et al. along with their response.)
28 Oct 2020
The statistical reliability of 267 GHz JCMT observations of Venus: No significant evidence for phosphine absorption. M. A. Thompson. Monthly Notices of the Royal Astronomical Society: Letters 501, L18-L22 (Feb 2021).
10 Dec 2020
Phosphine in Venus' atmosphere: Detection attempts and upper limits above the cloud top assessed from the SOIR/VEx spectra. L. Trompet, S. Robert, A. Mahieux, F. Schmidt, J. Erwin, and A. C. Vandaele. Astronomy & Astrophysics 645, L4 (Jan 2021).
24 Jan 2021
Complications in the ALMA Detection of Phosphine at Venus. A. B. Akins, A. P. Lincowski, V. S. Meadows, and P. G. Steffes. Astrophysical Journal Letters 907, L27 (1 Feb 2021).
25 Jan 2021
Claimed detection of PH3 in the clouds of Venus is consistent with mesospheric SO2. A. P. Lincowski, V. S. Meadows, D. Crisp, A. B. Akins, E. W. Schwieterman, G. N. Arney, M. L. Wong, P. G. Steffes, M. N. Parenteau, and S. Domagal-Goldman. Astrophysical Journal Letters 908, L44 (20 Feb 2021)
07 May 2021
Water activity in Venus's uninhabitable clouds and other planetary atmospheres. J. E. Hallsworth, T. Koop, T. D. Dallas, M.-P. Zorzano, J. Burkhardt, O. V. Golyshina, J. Martín-Torres, M. K. Dymond, P. Ball, and C. P. McKay. Nature Astronomy 5, 665-675 (Jul 2021).
07 June 2021
Reply to: No evidence of phosphine in the atmosphere of Venus from independent analyses. J. S. Greaves, A. M. S. Richards, W. Bains, P. B. Rimmer, D. L. Clements, S. Seager, J. J. Petkowski, C. Sousa-Silva, S. Ranjan, and H. J. Fraser. Nature Astronomy 5, 636-639 (Jul 2021).
(This response and the addendum below appear to deal competently with several of the proposed problems with Greaves et al. enumerated by Villanueva et al. and other authors. They provide enhanced evidence that the feature attributed to phosphine is detected robustly by both ALMA and the JCMT and that it is inconsistent with SO2.)
12 Jul 2021
published online
Volcanically extruded phosphides as an abiotic source of Venusian phosphine. N. Truong and J. I. Lunine. Proceedings of the National Academy of Sciences of the United States of America 118, e2021689118 (20 Jul 2021).
16 Jul 2021
Addendum: Phosphine gas in the cloud deck of Venus. J. S. Greaves, A. M. S. Richards, W. Bains, P. B. Rimmer, H. Sagawa, D. L. Clements, S. Seager, J. J. Petkowski, C. Sousa-Silva, S. Ranjan, E. Drabek-Maunder, H. J. Fraser, A. Cartwright, I. Mueller-Wodarg, Z. Zhan, P. Friberg, I. Coulson, E.Lee, and J. Hoge. Nature Astronomy 5, 726-728 (Jul 2021).

Venus image adapted from https://en.wikipedia.org/wiki/Venus#/media/File:Venus_-_December_23_2016.png
Maintained by DE Woon
Updated 25 July 2021