On Monday, a team of international scientists announced they had detected a chemical called phosphine in Venus’s atmosphere. Phosphine can be produced by lightning, volcanoes, and even the sun itself. But the levels of the chemical found in the skies around Venus were far more than what those sources typically produce, and in fact were more in line with the levels created by bacteria. The implication — that there might be life on Venus — sent the scientific community into a collective freakout.
The discovery came as a particular surprise to many because Venus hasn’t traditionally been a popular candidate for finding life outside of Earth. As the second planet from the sun, its surface temperature reaches highs of 900 degrees Fahrenheit and its sulfuric atmosphere is too hot and thick for oxygen-reliant organisms to breathe.
“Venus is hell. Venus is kind of Earth’s evil twin,” astrophysicist and study co-author David Clements told Time magazine. “Clearly something has gone wrong, very wrong, with Venus. It’s the victim of a runaway greenhouse effect.”
However, while its surface seems uninhabitable, the planet’s atmosphere holds potential. The temperature in the atmosphere is rather mild, reaching as low as 85 degrees Fahrenheit, and the clouds contain droplets with sulfuric acid and small amounts of water. The late Carl Sagan and Harold Morowitz pondered the possibility of life within the clouds of Venus back in 1967, though they didn’t have the evidence to make any official claims.
Finding phosphine in Venus’s atmosphere came about almost by accident. “This was an experiment made out of pure curiosity, really — taking advantage of [the James Clerk Maxwell Telescope’s] powerful technology, and thinking about future instruments,” team lead and astronomer Jane Greaves stated in a press release. “I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus’ spectrum, it was a shock!”
Planetary scientist and co-author Sara Seager explained to Time that the team “exhaustively went through every possibility and ruled all of them out: volcanoes, lightning strikes, small meteorites falling into the atmosphere. [...] Not a single process we looked at could produce phosphine in high enough quantities to explain our team’s findings.”
Which opened the door to microbial life as a possible source.
Despite their findings, the authors of the study, as well as other researchers, caution against making any definitive claims. Their discovery is but an arrow in the direction of a possible path, not necessarily the path itself.
“It’s not a smoking gun,” Clements said. “It’s not even gunshot residue on the hands of your prime suspect, but there is a distinct whiff of cordite in the air, which may be suggesting something.”
Still, the discovery itself is a thrilling indication that mankind may have been too quick to overlook Earth’s closest planetary neighbors. Venus has been ignored for so long due to its inhospitable surface that it’s difficult for scientists to understand just how significant this new finding will be. It might be time for Mars, the longstanding candidate for supporting extraterrestrial life, to share the spotlight with “Earth’s twin.”
“This is an astonishing and ‘out of the blue’ finding,” Seager told The New York Times. “It will definitely fuel more research into the possibilities for life in Venus’s atmosphere.”
There already appears to be interest in getting that research going. As NASA administrator Jim Bridenstine put it on Twitter: “It’s time to prioritize Venus.”