Was Life Discovered on Venus? Nope.

Last September, a new scientific discovery was reported all over the media. You might have seen some of the headlines, such as:

• Astronomers find possible sign of life on Venus (CBS News)
• Life on Venus? Astronomers See a Signal in Its Clouds (New York Times)
• Possible signs of life found on Venus (News release from London’s Natural History Museum)
• Is There Life On Venus? Extra-Terrestrial ‘Aerial’ Organisms May Exist In Its Clouds, Say Scientists (Forbes)
• Our crazy finding suggesting life on Venus (CNN)

I wanted to publish an article on this immediately, but decided to wait instead. Although it was obvious that the initial reports were highly sensationalized, I knew there would be more to talk about once the scientific community had time to digest the initial announcement.

Indeed, now that some time has passed, there’s a lot to learn from this. It’s a good example of what often happens in announcements about scientific research, especially if it is related to origins.

This will be a long article, so here’s a summary of what follows:

• The initial research was flawed, and some of its flaws were obvious from the beginning.
• When the media reported on it, the early stories were both overblown and for the most part, didn’t discuss the problems with the announcement.
• Now that the overall scientific community has had time to examine the research, even more problems have come to light.
• There are not now, nor were there ever, indications of life on Venus.

Now for a discussion of what happened. As events like this often do, this one unfolded in several stages.

Stage One: Scientists Cautiously Report Their Findings

The initial paper published in Nature Astronomy (“Phosphine gas in the cloud decks of Venus“) reported the discovery of phosphine gas (PH₃) in Venus’ atmosphere, and noted:

“The presence of PH₃ is unexplained after exhaustive study of steady-state chemistry and photochemical pathways, with no currently known abiotic production routes… PH₃ could originate from unknown photochemistry or geochemistry, or, by analogy with biological production of PH₃ on Earth, from the presence of life.“

Greaves et al., Phosphine gas in the cloud decks of Venus, Nature Astronomy volume 5, pages 655–664 (2021)

“Abiotic” means “no life.” Thus, the announcement basically said this:

• We detected evidence for phosphine gas in Venus’ clouds.
• We tried to find an explanation for the gas to be produced on its own, and couldn’t find one.
• On Earth, phosphine can be produced by bacteria.
• Perhaps this is the explanation for the phosphine we have found on Venus; it is being produced by life.

As I mentioned earlier, there were immediate problems with this announcement (more about this below). However, to their credit, the researchers were careful to say that life wasn’t the only possible explanation; maybe some unknown chemical process was responsible for their findings.

Stage Two: Reporters Sensationalize The Announcement

When the scientists announced their research, they were (correctly) cautious and avoided making definitive claims. But was this caution included in the media reports? All too often, it was not. Media stories (like the headlines above) tend to focus on the sensational aspects of a story, and that’s what happened here.

The public can be easily misled by this. Someone who only saw one or two of these reports, and wasn’t aware of the details, could easily wind up thinking, “we found life on Venus!”… even though the only thing that was (possibly) found was phosphine gas.

And as subsequent events showed, even this wasn’t necessarily true.

Stage Three: Problems Emerge

After the initial announcement was made, it was clear that there were multiple ways that the “possible life on Venus” idea could be wrong. Here are a few:

1. Maybe the data weren’t being analyzed correctly.
2. Or maybe the data were invalid for some reason.
3. Or maybe some gas was being actually detected, but it was something else that was being misidentified as phosphine.
4. Or maybe the idea that “we don’t know any other source for phosphine on Venus” would be challenged.

So, in the months following the announcement, how many of these problems were confirmed to exist? All of them.

Problem One was clear immediately, although you had to really dig into the details to notice it. In the Venetian data, the phosphine signal is very weak, and it’s dominated by noise. The researchers had to mathematically subtract the noise in order to reveal the signal.

Noise subtraction isn’t unusual. What is unusual is that the researchers used a 12th-order polynomial to do it.

High-order polynomials are powerful mathematical tools. If you aren’t careful, that power can work against you. They can fool you into thinking that a pattern is real, when it really isn’t.

Basically, the researchers constructed a highly customized mathematical process to “cancel out the noise”—but it’s so customized that it removes everything that doesn’t look like a phosphine signal.

In other words, it could take almost any set of data and make it look like evidence for phosphine gas, because that’s basically what it’s designed to do.

Overly-customized mathematics are a common source of error in scientific research. One tongue-in-cheek paper illustrated this danger by using an equation with only four parameters to construct a graph of an elephant:

Problem Two is that even if the data were being analyzed correctly, this wouldn’t matter if the data themselves weren’t valid. Two months after the initial announcement, it was revealed that the telescopes at ALMA (the Atacama Millimeter-submillimeter Array in Chile) were miscalibrated,, so the data that had been published were faulty. After ALMA released corrected data, the researchers re-ran their analysis. They announced that the phosphine signal was much weaker than they had previously thought, although they still believed it was there.

Problem Three is that even if Problems One and Two didn’t exist, and the researchers had actually found a legitimate chemical signal in Venus’ clouds, it might not even be phosphine. Several papers have pointed out that sulfur dioxide might be the correct explanation instead.

Problem Four is that even if the researchers found a legitimate chemical signal, and the signal were being produced by phosphine, this doesn’t say anything about the presence of life. Phosphine is a simple molecule, containing only four atoms, and some researchers believe it could be produced by straightforward chemical reactions, without life being necessary. For example, Lee Cronin at the University of Glasgow commented:

“[it’s] super easy to make in the laboratory… You just combine phosphorus and a base. I’ve made it by mistake.”

Cronin suggested that sulfuric acid (which often falls as rain on Venus) could react with phosphorus on the surface, which would produce phosphine gas.

Stage Four: The Hypothesis is Disproved

Due to all of these problems, the “life on Venus” proposal has been thoroughly discredited. In fact, Problems Two through Four are almost redundant. The first problem alone (overly customized mathematical processing) is enough to falsify the claim.

…But the Public is Still (Mostly) Misinformed

As the scientific community discussed and confirmed the problems with the announcement about Venetian phosphine, relatively few media outlets reported on it. And the stories that were published got far less attention and hype than the original ones did.

Unless you were really paying attention, you probably didn’t even see any media stories on this. So, for the most part, the public has come away from this under the false impression that scientists probably discovered evidence for life on Venus.

Lessons to Learn

The “life on Venus” announcement is an excellent example of a common problem in science reporting:

• When an announcement is made, the media often publish sensational stories about it.
• Later, when the announcement turns out to be false, it receives very little attention.

I’m not accusing any reporters or editors of doing this on purpose. It’s just the nature of how the media cycle operates. Clearly, “we found life on Venus!” is a much more exciting story, and will get much more coverage, than “we might have found some phosphine gas.”

And the most boring story of all is “oops, we were wrong.” Even if it were published, that one will get little attention.

So, when you see a hyped-up claim about a new scientific discovery, wait to see what happens after more information comes to light. You’ll usually find that patience is rewarded.