Is there life on Venus? Probably not.

We could leave it there, except for the fact that there are several good scientists who do not dismiss the possibility, so there is definitely something to discuss. Also, we have to admit that we do not really understand the conditions under which life can evolve, or at least survive, and accept that there is life on Earth in niches (inside nuclear reactors, for example, or deep down in cold, dark frozen lakes) where no one expected to find it until it was discovered recently. Certainly, if we want to know whether we are alone in the Universe, and most of us do, we should leave no stone unturned.

Possible habitats on Venus

There are two very different environments where we might look for life on Venus: in the clouds and on the surface. Most of the research to date has focused on the former, for the obvious reason that the temperatures and pressures near the cloud tops are close to those at the Earth’s surface where we know that conditions suit life forms of many kinds. There is also a supply of liquid water, widely accepted as a prerequisite for life of any kind. There is also plenty of energy, as solar radiation beats down on the cloud tops with only moderate amounts of attenuation during its passage through the upper atmosphere. The vigorous dynamical activity, providing mixing and a strong diurnal effect, is all to the good. Finally, we already have evidence for chemical activity, for instance that which converts sulphur dioxide to sulphate, and this is no doubt only the tip of the iceberg as far as chemistry is concerned, and in a basicallyCO2 atmosphere some of it will be pre-organic (at least), providing further sources of energy and the compounds that might be the building blocks of life.