New study fuels discussion about the habitability of the Venus clouds – Sidereal Messenger

A new study suggests that, despite having sufficient temperature and pressure for life, Venus’ clouds are unlikely to harbor microorganisms. The reason? Lack of water. The new work is led by John Hallsworth of Queen’s University in Belfast, UK and Chris McKay of NASA’s Ames Research Center and is published in the latest edition of Nature Astronomy.

It’s another piece of research that shows how interest in our closest neighbor (and completely inhospitable with temperatures of 460 ° C on the surface) has recently rekindled, especially after the detection of phosphine (a possible but unlikely marker in Venus). Clouds) by Jane Greaves’ Group at Cardiff University, UK, last year. Last month NASA and ESA announced new missions to Venus for the next few years.

Of great interest is the prospect that in the distant past this world might have been fully habitable, with oceans and everything. Life could arise in such an environment. As the planet dried up, microorganisms may have found permanent abode in the clouds of the upper atmosphere, where conditions are more comfortable, albeit extremely acidic and with very little water. This is where the study by the Hallsworth and McKay teams comes in.

Based on basic chemical principles of the composition, temperature and pressure of the atmosphere, the researchers researched an index called “water activity”, which compares the partial pressure of water vapor in a solution with a standard value. The group calculated the activity of water in the sulfuric acid solutions of the Venusian clouds and found it to be 0.004, less than a hundredth of the 0.585 required in this regard by the most extreme forms of life on Earth.

This led the authors to categorically address the topic and describe the Venus clouds as “uninhabitable”. However, other experts urge caution. The problem is not the results, but the assumptions that lead to them. “The work is solid in that the calculations were done correctly,” says David Grinspoon, an astrobiologist at the University of Colorado (USA). “However, the study’s conclusions are overconfident because we know less about the atmosphere of Venus and the nature of life than the authors assume.”

Grinspoon points out that not only is there evidence that Venus clouds are not only made of sulfuric acid with a drop of water, as the work suggests, but that they are not homogeneous and offer environments very different from a simplified average suggests. In short, there is a lack of data.

Considering how can the problem be solved? There’s only one way to go: we really need to make more observations and send new probes over there to collect more data.

This column is published in Folha Corrida on Mondays.

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