Since the whole detection of phosphine saga from last year, there has been a renewed interest in Venus, not just an “Earth-Twin gone bad” but also as a world with the potential for life. Life there would have to be quite peculiar for sure and a new study now suggests that it is at least theoretically possible. 

The work, published in Proceedings of the National Academy of Sciences, starts from historical tentative detections of ammonia from the Venera 8 and Pioneer Venus probes, from the Soviet Union and the USA respectively. Ammonia shouldn’t be present on Venus, so if it’s really there we are missing the crucial understanding of the process that is producing it. 

The process this international research team suggests is certainly a bold one. What if there is life in the clouds of Venus and it is actually the source of the ammonia? Then the extreme environment of the clouds of Venus rich in sulfuric acid might be modified into something more livable. The ammonia would neutralize the sulfuric acid and start a chain of chemical reactions that would explain the anomalies scientists have so far found in the atmosphere of the planet. 

“No life that we know of could survive in the Venus droplets,” co-author Sara Seager, from MIT, said in a statement. “But the point is, maybe some life is there, and is modifying its environment so that it is livable.” 

Extraordinary claims require extraordinary evidence and the scientists know what that should be. They have provided a list of things that future exploration of Venus could spot. From confirming the presence of ammonia and oxygen to evidence that sulfur dioxide is being neutralized into ammonium salts, to detecting the presence of organics. 

“This hypothesis predicts that the tentative detection of oxygen and ammonia in Venus’s clouds by probes will be confirmed by future missions, and that both life and ammonium sulphite and sulphate are present in the largest droplets in the lower part of the cloud,” co-author Dr Paul Rimmer, from the University of Cambridge, said in a statement.

“There are also several remaining mysteries: if life is there, how does it propagate in an environment as dry as the clouds of Venus? If it is making water when neutralising the droplets, what happens to that water? If life is not in the clouds of Venus, what alternative abiotic chemistry is taking place to explain this depletion of sulphur dioxide and water? Future lab experiments and missions will be able to test these predictions and may shed light on these outstanding mysteries.” 

There are at least three missions that will visit Venus. NASA’s VERITAS and DAVINCI+ Venus missions are expected to launch between 2028 and 2030. The European Space Agency’s EnVision Venus orbiter first launch window starts in 2031. These missions could test this hypothesis.