Life on Venus? Astronomers see hint of life in clouds of Venus

• Astronomers spotted the chemical signature of phosphine, a gas that on Earth is only associated with life.
• Venus is a very challenging environment for life of any kind.
• The new discovery was published in a paper in the peer-reviewed British journal Nature Astronomy.

Scientists Monday announced the discovery of a possible sign of life high in the clouds of Venus, according to a new study.

Using telescopes based in Chile and Hawaii, astronomers spotted in Venus' clouds the chemical signature of phosphine, a noxious gas that on Earth is only associated with life.

Based on the many scenarios the astronomers considered, the team concluded that there is no explanation for the phosphine detected in Venus’ clouds, other than the presence of life.

“This means either this is life, or it’s some sort of physical or chemical process that we do not expect to happen on rocky planets,” said study co-author and Massachusetts Institute of Technology research scientist Janusz Petkowski.

Study co-author Sara Seager, an MIT planetary scientist, said researchers “exhaustively went through every possibility and ruled all of them out: volcanoes, lightning strikes, small meteorites falling into the atmosphere. … Not a single process we looked at could produce phosphine in high enough quantities to explain our team’s findings.”

The phosphine could be coming from some kind of microbes, probably single-cell ones, which live their entire lives in the 10-mile-deep clouds. The microbes could be microscopic organisms that float free of the planet’s scorching surface, with access to water and sunlight, but needing to tolerate very high acidity.

Study lead author Jane Greaves of Cardiff University in Wales said that “this was an experiment made out of pure curiosity, really. I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus’ spectrum, it was a shock!”

Venus is a very challenging environment for life of any kind. Life is not possible on its surface, with its boiling hot landscape, where temperatures reach 900 degrees Fahrenheit, and stifling air that is drier than the driest places on Earth.

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There is, however, a narrow, temperate band within Venus’ atmosphere, about 30 miles above the surface, where temperatures range from 30 to 200 degrees Fahrenheit, according to MIT. Scientists have speculated, with much controversy, that if life exists on Venus, this layer of the atmosphere, or cloud deck, is likely the only place where it would survive.

And it just so happens that this cloud deck is where the team observed signals of phosphine.

“This phosphine signal is perfectly positioned where others have conjectured the area could be habitable,” Petkowski said.

Life is definitely a possibility, but more proof is needed. Further observations and modelling are needed to explore the origin of phosphine in Venus’s atmosphere, scientists said.

Seager told CNN that "our hoped-for impact in the planetary science community is to stimulate more research on Venus itself, research on the possibilities of life in Venus' atmosphere, and even space missions focused to find signs of life or even life itself in the Venusian atmosphere."

The new discovery was published in a paper in the peer-reviewed British journal Nature Astronomy.