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Life in Venus Clouds

Could Alien Life Exist in Venus' Mysterious Clouds?

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Most people, when they think of the planet Venus, conjure up images of a hot and steaming planet surrounded by highly acidic clouds that would extinguish or prevent any life from ever existing there.   However, just above the cloud decks of the planet, there exists the most Earth-like conditions in our entire solar system. 

This has prompted some astrobiologists, such as Dirk Schulze-Makuch from Washington State University, to suggest that there is in fact a possibility for life to exist, not on Venus itself, but approximately 50 to 65 kilometers above the surface in its clouds where there is free oxygen and temperature and pressure similar to that on Earth. 

Makuch is particularly interested in the fact that the clouds of Venus seem to absorb more ultraviolet light than they should.  In fact, there is enough ultraviolet (UV) to give lethal sunburn to anything without adequate protection.  However, one hypothesis is that molecular rings of sulphur, which are plentiful in the atmosphere of Venus, could be giving something just that kind of protection.  These molecules absorb harmful UV and radiate it away.

The properties of Venus’ clouds are not just mysterious due to the unusual amounts of UV that they absorb. They also contain two types of molecules that logically should not be found together – sulphur dioxide and hydrogen sulphide (when in the same place, they react with each other).

Another unexpected chemical in Venus’ atmosphere is known as carbonyl sulfide (OCS). On Earth, carbonyl sulfide is so difficult to create through inorganic processes that it’s been used as an “unambiguous indicator of biological activity“.

Finally, Venus’ clouds contain another strange phenomenon – the so-called “mode 3 cloud particles.” The clouds of Venus are a menagerie of tiny droplets and ice crystals made up of the various chemicals found in the atmosphere. These cloud particles are normally fairly easy to identify, but the mode 3 particles are still a mystery.  They’re large, non-spherical, and they contain plenty of sulfuric acid.  David Grinspoon, curator of astrobiology at the Denver Museum of Nature and Science, has suggested that those cloud particles are even the same size as bacteria.  It could be that life already exists in the mysterious clouds of Venus, just waiting to be discovered.

By John Black

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