These Scientists Were Shamed for Claiming Signs of Life on Venus, But Now They're Back With More Evidence

This new theory for life on Venus is "not completely crazy."

Venus Sky Trap

In 2020, a team of researchers led by Jane Greaves from Cardiff University in the UK announced the discovery of a significant source of phosphine, a "biosignature" gas that's closely related to life on Earth, in the clouds above Venus.

While plenty of questions remained regarding the habitability of the highly acidic environment, the findings suggested that the clouds just might be home to life.

Perhaps unsurprisingly, the findings proved highly controversial, with other scientists disputing the results.

Earlier this month, however, Greaves and her colleagues presented fresh evidence for an upcoming scientific paper at this year's Royal Astronomical Society meeting in Hull, England.

This time, it's about new evidence for the presence of ammonia, another gas that's overwhelmingly the result of biological activity on Earth. It's not a slam dunk, but Greaves' crew is clearly building the case for an otherworldly ecosystem on the second planet from the Sun.

"The exciting thing behind this would be if it’s some kind of microbial life making the ammonia, because that would be a neat way for it to regulate its own environment," Greaves told CNN. "It would make its environment much less acidic and much more survivable, to the point it’s only as acidic as some of the most extreme places on Earth — so not completely crazy."

Cloud Atlas

But the gulf between "not completely crazy" and compelling evidence for extraterrestrial life is enormous.

"There’s a lot of other processes that could go on, and we just don’t have any ground truth to say whether that process is possible or not," Greaves told CNN.

"We understand why ammonia might be useful to life," added Imperial College London astrophysics reader Dave Clements, who presented separate evidence for the existence of ammonia on Venus at the meeting. "We don’t understand how the ammonia is produced, just like we don’t understand how the phosphine is produced, but if there is ammonia there, it would have a functional purpose that we can understand."

Other experts also expressed the need for caution, despite our understanding of the extraterrestrial environment changing considerably in light of the latest findings.

University of Aberdeen planetary sciences professor Javier Martin-Torres challenged Greaves' findings in a 2021 paper, concluding that the water availability in the planet's atmosphere was far too low to make it a habitable place.

The most recent finding that ammonia may be able to make a dent in the highly acidic environment, however, has him intrigued. Now he tells CNN that it "challenges our understanding and suggests that more complex chemical processes might be at play."

Fortunately, NASA is planning to have a probe dubbed Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) plunge through the Venus atmosphere in the 2030s — a mission that could finally shed more light on the matter.

More on the findings: Scientists Spot Possible Signs of Life in Clouds of Venus