By Michelle Starr
Venus, but for some quirk of planetary evolution, could have been Earth or vice versa.
The two planets share many similarities, but where Earth is moist and temperate, Venus has a scorching hot surface shrouded with a thick atmosphere of toxic and acidic fumes.
Nevertheless, that atmosphere is not entirely inhospitable, according to new research. Although the chance microbes might thrive in such an environment is slim, it’s plausible enough to warrant considering.
“The clouds can support a biomass that could readily be detectable by future astrobiology-focused space missions from its impact on the atmosphere,” write a team led by molecular biologist William Bains of Cardiff University in the UK and MIT in the US in a paper published in Astrobiology.
“Although we consider the prospects for finding life on Venus to be speculative, they are not absent. The scientific reward from finding life in such an un-Earthlike environment justifies considering how observations and missions should be designed to be capable of detecting life if it is there.”
The prospect of life on Venus has loomed large in the collective imagination of Earth since the discovery of traces of phosphine gas in the planet’s atmosphere in 2020.
Phosphine can be produced by biological and geological processes, and its detection has been hotly debated. The debate did ignite a keen scientific interest in re-examining our presuppositions about Venus’s habitability, or lack thereof.
The surface itself is unlikely to be habitable to life as we know it: Temperatures on the Venusian ground average around 464 degrees Celsius (867 Fahrenheit). Life’s chemistry requires a solvent (here on Earth, that’s water), and those temperatures are incompatible with any liquid. But Venus’s skies, although much more temperate, are laced with clouds of sulfuric acid and were not thought to be much better.