Chemical hints of life are found in old data from Venus probes and landers. Could microbes exist in Venusian clouds? | fr584's Blog

Life in Venus' clouds may be the best way to explain some curious anomalies in the composition of its atmosphere, claimed University of Texas astrobiologists in 2002. They scoured data from NASA's Pioneer and Magellan space probes and from Russia's Venera Venus-lander missions of the 1970s.

Solar radiation and lightning should be generating masses of carbon monoxide on Venus, yet it is rare, as though something is removing it. Hydrogen sulphide and sulphur dioxide are both present too. These readily react together, and are not usually found co-existing, unless some process constantly is churning them out. Most mysterious is the presence of carbonyl sulphide. This is only produced by microbes or catalysts on Earth, and not by any other known inorganic process.

The researchers' suggested solution to this conundrum is that microbes live in the Venusian atmosphere. Venus's searing hot, acidic surface may be prohibitive to life, but conditions 50 kilometres up in the atmosphere are more hospitable and moist, with a temperature of 70°C and a pressure similar to Earth.