A new study throws cold water (vapor?) on an earlier paper that suggested that aerial life forms could exist in Venus’s massive cloud cover:

Researchers from the University of Cambridge used a combination of biochemistry and atmospheric chemistry to test the ‘life in the clouds’ hypothesis, which astronomers have speculated about for decades, and found that life cannot explain the composition of the Venusian atmosphere.

Any life form in sufficient abundance is expected to leave chemical fingerprints on a planet’s atmosphere as it consumes food and expels waste. However, the Cambridge researchers found no evidence of these fingerprints on Venus.

University of Cambridge, “No signs (yet) of life on Venus” at ScienceDaily (June 14, 2022) The paper is open access.

The contention in the earlier paper was that chemicals present in Venus’s clouds are consistent with production by life forms.

Although the authors of the study published last week, Jordan Chortle and P. B. Rimmer, say that the specifics of Venus’s atmospheric chemistry are not a biosignature (evidence of life), they stress that the atmosphere on Venus is nonetheless “strange.”

They hope that their work will assist in identifying other promising sites for extraterrestrial life:

”To understand why some planets are alive, we need to understand why other planets are dead,” said Shorttle. “If life somehow managed to sneak into the Venusian clouds, it would totally change how we search for chemical signs of life on other planets.”

“Even if ‘our’ Venus is dead, it’s possible that Venus-like planets in other systems could host life,” said Rimmer, who is also affiliated with Cambridge’s Cavendish Laboratory. “We can take what we’ve learned here and apply it to exoplanetary systems — this is just the beginning.”

University of Cambridge, “No signs (yet) of life on Venus” at ScienceDaily (June 14, 2022) The paper is open access.

They hope their method of analysis will prove a help later this year when the James Webb Space Telescope starts returning images of planets outside our solar system.

Phosphine gas, known on Earth to be produced only by life forms, has been one of the arguments for life on Venus:

We really won’t know until the probes many are now sending start relaying transmissions.

Actually, Jupiter’s moon Europa has long been considered a better bet than Venus because of known water and organic chemicals. The Europa Clipper (projected launch date of October 2024) will be doing a detailed reconnaissance flyby of the promising moon.

You may also wish to read: Why researchers focus on possible life on Venus. Chemicals that we shouldn’t find unless they are produced by life forms are sparking interest in exploring Venus from both public and private sources. Extremophiles — life forms that live under extreme conditions — are showing that survival of life is a much less severe problem than origin of life.

and

Why scientists think there might be life on Europa. Jupiter’s moon Europa, somewhat smaller than Earth’s moon, may have surface water and organic chemicals, researchers say. Europa, despite being outside the conventional “habitable zone,” may be a better bet for life than Mars. The launch of the Clipper in 2024 will tell us more.