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Because liquid water is the key to life as we know it, if Venus had water on its surface for billions of years it\u2019s possible that microbial life emerged during that time. We don\u2019t know for sure, though, and looking for evidence of past life on Venus is almost impossible with current technologies.<\/p>\n
Although orbiters can teach us a lot about a planet, to search for signs of past life we need to take a much closer look. On Mars, we look for past microbial life by sending rovers like Curiosity and Perseverance to analyze rock samples. But Venus is a much more difficult place to explore on the surface. Only a handful of landers have successfully operated on the Venusian surface. Many more have tried and failed, but even the successful missions were only able to operate for hours at most before being destroyed by the planet\u2019s extreme conditions. This doesn\u2019t give spacecraft enough time to do things like collect and analyze rock samples to look for microscopic fossils.<\/p>\n
Although life as we know it is almost certainly impossible in the harsh conditions on the surface of Venus, it\u2019s possible that it could survive in the Venusian atmosphere. Although Venus\u2019 lower atmosphere contains toxic clouds of sulfuric acid, at higher levels the conditions are much less deadly.\u00a0<\/p>\n
In 2020 scientists announced they found phosphine gas \u2014 a potential biosignature, i.e. a chemical strongly associated with biological processes \u2014 in Venus’ clouds 50 kilometers (roughly 31 miles) above the surface, where temperatures and pressures are much more Earth-like. Phosphine\u2019s presence has since been disputed, then later reclaimed but with an alternative explanation for its origins, disputed once again, and redetected lower in the atmosphere. The verdict on whether phosphine exists in the clouds of Venus, and whether its presence would mean there were life forms producing it, is still very much undecided.<\/p>\n<\/div>\n