Venus might seem like a terrible place for life, but some kinds of life might still be possible there. A recent study from MIT discovered that the basic ingredients for life can survive in the thick sulfuric acid clouds of Venus.
In the past, people thought Venus could be a nice place, especially in science fiction stories. But as we learned more, it turned out to be a harsh environment. It’s extremely hot, with temperatures that can melt lead, and the air pressure is like being deep underwater. Plus, the thick clouds are made of sulfuric acid, and the air is mostly carbon dioxide. So, living on Venus doesn’t seem like a good idea.
While many people are interested in planets like Mars, or moons such as Europa, Enceladus, and Titan, Venus has become more important in recent years. Scientists think that conditions might be better for life at altitudes between about 48 and 60 km (30 and 37 miles) above the surface. There, the temperature and pressure drop, and there’s more water. Interestingly, this is where strange dark patches have been seen in the Venusian clouds. These patches look like they could be made by a bacteria species found on Earth.
But there’s a big problem for life in those clouds—sulfuric acid. Previous studies suggested that other particles in the air might protect microbes, but a new study found that they might not need protection. They could be okay floating around in sulfuric acid.
Researchers at MIT put all 20 “biogenic” amino acids – chemicals essential for life – into vials of sulfuric acid at concentrations of 81-98%, levels found in Venusian clouds. Surprisingly, 19 of them stayed stable even at the highest concentrations. Their molecular structures remained intact for the entire four weeks of the study, so the researchers ended it there because there were no further signs of change.
“We’re discovering that the basic building blocks of life on Earth can survive in sulfuric acid, which is interesting for the idea of life on Venus,” said Sara Seager, one of the study’s authors. “It doesn’t mean that life on Venus would be the same as on Earth. We know it can’t be. But this research suggests that Venus’ clouds might have the complex chemicals necessary for life.”
Amino acids aren’t the only life ingredients that can survive in sulfuric acid: The team has also shown that some fatty acids and nucleic acids can withstand it. However, the scientists are careful to note that just because these complex organic chemicals can survive there, it doesn’t mean life actually exists on Venus. It’s uncertain whether these ingredients are present and, if they are, whether they’ve formed into lifeforms through evolution. Additionally, the researchers acknowledge that the actual chemistry of Venus’ atmosphere is much more complicated than what they recreated in the lab.
This study adds some support to the idea that there might be life on Venus, but right now, it seems like the skeptics are still in the lead. One exciting discovery in 2020 was the detection of phosphine in Venus’ atmosphere, a chemical usually linked to microbes on Earth. However, later research suggested it was likely just sulfur dioxide. Some scientists argue that Venus doesn’t have enough water or other signs of life.
But we might get a clearer answer soon. The upcoming Venus Life Finder mission will send a spacecraft to investigate those acidic clouds for any signs of life. It’s set to launch by the end of 2024.
