The sky of Venus may contain traces of alien life, according to scientists at the Massachusetts Institute of Technology.
In the search for extraterrestrial life, the second planet from our Sun has long been ignored. Why? The surface of Venus reaches temperatures exceeding 426 degrees Celsius, and its dense atmosphere exerts nearly 100 times more pressure on objects than Earth's atmosphere. Venus experiences sulfuric acid rain and corrosive chemicals.
For all these reasons, most scientists have focused on finding signs of ancient alien life on Mars, Saturn's natural satellite Enceladus, or Europa, Jupiter's unique moon. But Earth's closest neighbor may have been worth watching all along, writes Big Think.
A new paper published in Nature Astronomy suggests that Venus's atmosphere may contain significant amounts of phosphine – a chemical known to be a byproduct of life.
This is not definitive proof of life. Phosphine (PH₃) can be produced through inorganic processes, such as interactions involving sunlight, surface minerals, volcanic activity, and lightning.
But the study's authors considered these and other potential sources. They created computer models to test whether they could simulate phosphine production on Venus. During the study, they managed to produce small amounts of the chemical – but nowhere near as much as multiple observatories have detected in Venus's clouds.
So for now, scientists do not know what is producing the phosphine. Alien life remains a compelling explanation.
"Technically, biomolecules have been found in Venus's atmosphere before, but these molecules are also associated with a thousand things other than life," said study co-author Clara Sousa-Silva to MIT News. "The reason phosphine is special is that without life, it is very difficult to make phosphine on rocky planets. Earth was the only terrestrial planet where we had found phosphine – because here, there is life. Until now."
If life is indeed producing the chemical, it is likely anaerobic life – organisms that do not require oxygen. Interestingly, such life forms would probably be "airborne" aliens, floating within a relatively thin, habitable band of the atmosphere, surrounded by otherwise hellish conditions.
How did these life forms get there? Sousa-Silva explained:
"A long time ago, Venus was thought to have oceans and was probably as habitable as Earth. As Venus became less hospitable, life had to adapt, and it may now survive in this narrow envelope of the atmosphere where conditions are still tolerable."
The researchers emphasized that detecting phosphine in Venus's atmosphere is not necessarily proof of life, but rather "an anomalous and unexplained chemistry." Nevertheless, they hope to confirm their findings with additional observations, including a potential probe mission – which would be NASA's first since Pioneer Venus 2 entered the Venusian atmosphere in 1978.
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