The discovery of a possible sign of life in Venus’ clouds sparked controversy. Now, scientists say they have more proof
Samantha Marquart-Pyatt
9/22/2026
Atmospheric Gases
Media article: https://www.cnn.com/2024/07/29/science/venus-gases-phosphine-ammonia
Paper #1 (2020): https://www.nature.com/articles/s41550-020-1174-4
Paper #2 (2026): https://arxiv.org/pdf/2409.13438
Topic
Detection of possible biomarker gases on Venus.
Abstract View
Phosphine (PH3) is a colorless, flammable gas that is highly toxic. Some believe that phosphine could be a biomarker, as it is of organic origin on Earth from anaerobic microorganisms. The significance of Phosphine detection lies in the fact that it could potentially indicate some form of life (anaerobic microorganisms) producing the gas, or unknown photo/geo chemistry occurring. This, however, is a working theory and not actually proven.
The Paper(s)
Paper #1 - (HERE)
The first paper analyzed was the original 2020 study that was peer-reviewed and published, which the article mentions. They mention in this a “ripple” with the ALMA measurement, which turned out to be a calibration issue. ALMA actually went out and published a statement (https://www.eso.org/public/announcements/ann20030/) because they think it could have had an impact on the phosphine detection. Since other sources had mentioned being unable to replicate the detection results, this ripple could be part of the explanation as to why Greaves’ team (who Clements worked with) got such high detection rates (20 ppb). Later estimates say that if there is any, it is more likely to lie between ~1- 5 ppb instead.
They confirmed phosphine formation was unfavorable on the surface and subsurface by running 75 reactions and 1000s of conditions. Their overall conclusions from the results, as they mention the purpose of the experiment to be a benchmark for future developments, were that there could be unknown photo/geochemistry occurring or maybe a sign of life. Acknowledgement was given that information is lacking, so these were hypotheses.
Paper #2 - (HERE)
This was submitted in September 2024, after the meeting where quotes about the data were published. Strangely, in the abstract, they say that “comprehensive studies rule out all known abiotic sources” – indicating that they think a life form producing phosphine on Venus is unlikely. This is the very same data they were talking about that is referenced in the article, where they do allow a hypothetical life on Venus producing phosphine.
There is considerable interest in the detection of phosphine, even if not an indicator of life, due to the fact that it is a reducing chemical and Venus has an oxidizing atmosphere. This detection, therefore, sparked challenges on many fronts by other researchers, and the authors indicate that each suggestion that the detection was an error has been disproven. A large argument made is that phosphine gets destroyed by solar photolysis during daylight, so higher measurements would occur at night going into day. In 2024, they started a long-term project to investigate how phosphine abundance could vary in relation to other properties, such as time of day or abundance of other chemical species.
They then return to the statement that biological origin cannot be eliminated since there is no established chemical origin. They also have a section in which they say their data has been peer-reviewed, as well as talking about public reception where they speak about data before it being published (and, by extension, peer-reviewed).
The Article (HERE)
This piece of media comes from CNN in July of 2024, where the title already pulls viewers in by mentioning “possible sign of life in Venus’ clouds”. Most significantly, the contents of this article come mostly from quotes from a Royal Astronomical Society meeting that happened on July 17th of 2024. Clements acknowledges his old data from a 2020 paper, and then also mentions his new data, which backs and goes even further now to detect a second gas, ammonia. The original data was brought under scrutiny because numerous other teams tried and could not recreate phosphine detection, and there was a strong belief that Clement's team's data was caused by an error of some sort. This new data is unpublished, so comments will not be made on the accuracy of the article’s depiction of unpublished, non-peer-reviewed data (see aside below for more). The rest of the article describes the timeline and analysis techniques the group used previously. They provide context for the new information, using the old paper and data to lead into what the team is doing now with new data. Clements reported 140 times as much data as their original detections, yet again indicating phosphine. Another team also found evidence of ammonia, which Clements indicates as a likely biomarker, saying, “if there is life on Venus producing ammonia, we do have an idea why it might be wanting to breathe ammonia”. They continue by describing why the presence of ammonia or phosphine is unexpected on rockier planets due to hydrogen escape when the planets originally formed. Coming in with the studies challenging the results is also critical, especially since multiple different teams (including NASA telescope facilities) were unable to replicate these findings. They end with caution rather than optimism since it was being debated by researchers, with a 2021 study’s findings challenging the phosphine findings and taking the stance that life is not possible in Venus’s clouds because of the “harsh and seemingly inhospitable conditions”.
Analysis
It’s pretty difficult to analyze how accurate the media article is, given how messy the situation is with Clements and his papers on phosphine detection on Venus. He is fairly inconsistent with how he interprets his data when presenting it. Even after 6 years, he is still very stuck on not discounting the possibility of life, which is fair, but he also still does not seem to highly value the work of others in the same field. Because the article is also taking statements from said man from unpublished data, which was not submitted until afterwards, I cannot confirm if the contents were changed from the direct quotes given. This really feels like Schrödinger’s article. I think I will give it an 8/10 because they did do a good job reporting on data from the 2020 paper, as well as giving some layman explanations for certain findings and what they can mean. An example of this is when they talk about hydrogen escape on planet formation instead of stating the planet as oxidizing or reducing, since not everyone knows what that means. It would be unfair to analyze the content based on a later publication, and I could not locate these quotes in further context. (From the way this man wrote in his later paper, however, I believe they were in appropriate amounts of context.)
It is still very striking to me that he said in this meeting that they believe life is possible on Venus, then in the abstract of said paper says it is unlikely, and then doubles down again in a section saying it is still possible because nobody has disproven it yet. He is objectively correct in this, but the tone is rather harsh and lacks the specificity that, if it is some form of microorganism, it is nothing we have on Earth, further making it harder to prove existence.
ASIDE FROM ABOVE: (Even though he claims this, all of what he says comes from data that has neither been published nor peer-reviewed at the time. It is also worth noting that the context in which these quotations are taken is at a meeting for the society, which can act somewhat like a research/grant proposal setting where a large overview and long-term promising results may be shared. This, therefore, calls into question the points made in the CNN article, since the analysis is then further exaggerated as the media does to draw our attention in. )
I’m very curious as to what you all think about this scenario, as I think it brings up a good point about scientific communication and collaboration. I also would like to know if you all have more ideas on how the article could be rated given this context.
Fun additional comment at the end of the CNN article:
This is such an interesting article – I'm so glad you picked it because I'd never seen these headlines before! I definitely agree with your analysis and find the label of "Schrodinger's article" to be quite accurate. Are there any other potential biomarkers, besides phosphine and ammonia, that scientists have been interested in? If these have also lead to likely dead-ends, how far do scientists think we need to study before we can say (with somewhat certainty) that there probably isn't life on Venus? Also (a little bit of a non-science question), do you think headlines like these might make the general public less confident in science, since there's so much uncertainty and vocal debate? This is a question I always find myself coming back to when scientific conversations make popular headlines.
ReplyDeleteHi Gabriella, great question! I think this can definitely give people a hesitation on communication, especially when it is about something on another planet. There can already be skepticism on these topics since it doesn't seem tangible to some people. I do, however, think the controversy was not super widespread in mass media for a similar reason: people do not understand the topic, so it's hard to get them to form a solid line of thought on the topic. I could be wrong, though, but I did not hear about this in 2024. It could also be because it was in the UK.
DeleteThis is very interesting, I've never even heard of this topic before. i agree that it makes the CNN article difficult to evaluate because some of the information they reported came from data that had not been peer-reviewed yet. one question is do you think scientists should share preliminary findings with the public before they have been review, especially with this major impact on how we understand the topic?
ReplyDeleteHi Bryanna, great question! I think it places people in a difficult spot because there is a real worry about people "stealing" their research and trying to publish a similar experiment faster. I also do think the defense mechanism to what is mentioned prior is publishing preliminary results, which then causes limitations when they have results since they have to change how they talk about the information since including the same initial information can cause plagiarism flagging.
DeleteThis is a very interesting article. From your description, it sounds like Clements is placing the burden on others in the field to disprove him, rather than accepting the burden of proof himself. I second Bryanna's question about whether unreviewed (disputed) findings ought to be published in mainstream media, especially given Clements' financial incentive to embellish his work. There's a great deal of uncertainty in science that is sometimes overlooked. Did you feel CNN presented his findings critically enough for a general audience, and if not, how do you suggest CNN present them differently?
ReplyDeleteHi Vee, great question! I do think CNN presented the findings critically enough, since I would consider a big point to be about the controversy and the basis of phosphine findings significance. I do think a drawback to this is not addressing the shortcomings of the scientific communication happening when they talk about unpublished, and even unsubmitted, data. There is no guarantee further editing was not done between this talk and when they submitted the paper just over a month later.
DeleteHi Samantha, what a drama-filled situation! I see how this has the potential to upset the general population over confusing claims and seemingly "wasted" time. I saw that the original paper by Greaves et al published an addendum in 2021 claiming that their 20 ppb measurement was sound and not due to a ripple. Do you have any idea why their 2020 measurements were still so far off from other group's estimates of ~1-5 ppb? Thanks for the post.
ReplyDeleteHi Rain, good question! ALMA released a statement also saying their equipment which Greaves' team used had a minor calibration error. It is interesting to me they claim such sound data despite this, but my best guess is it following their argument of nighttime vs daytime measurement; nighttime would have higher phosphine readings and daytime lower. I am not sure of such a high increase, though.
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