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Life on Venus?

grmcdorman said:
Clouds (on Earth, and I believe at the specified altitudes on Venus) are liquid water; it's just very fine droplets. Water vapour is largely transparent.
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The clouds on Venus are not water.

Astronomers have detected that the atmosphere of Venus consists of 0.002% water vapor. Compare that to the Earth’s atmosphere, which contains 0.40% water vapor
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https://www.universetoday.com/36291/is-there-water-on-venus/

In other words Venus' atmosphere has 0.5% of the water of Earth's atmosphere.
 
I think if there's life there, it somehow isn't water-based.

I.e. even our extremophile lifeforms wouldn't work there, due to the lack of H2O.
 
rjh01 said:
The clouds on Venus are not water.



https://www.universetoday.com/36291/is-there-water-on-venus/

In other words Venus' atmosphere has 0.5% of the water of Earth's atmosphere.
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The clouds are mostly sulfuric acid, apparently. Water is present; it varies by altitude. Not sure what altitudes they're referring to, but the lower clouds have 30±15 parts per million by volume [https://www.sciencedirect.com/topics/earth-and-planetary-sciences/venus-atmosphere]. Another paper quotes ~15 ppm at 60km altitude [http://www.issibern.ch/teams/venusso2/multimedia/pdf/Krasnopolsky_06.pdf], dropping to ~5 ppm at 63 km.

Whether that is enough, and whether the other compounds are problem, remains to be seen. Extremophiles on Earth can live in very harsh conditions, but as mentioned below arising those conditions is different from adapting to them. (Unless, of course, Venus was more hospitable in the distant past, allowing life to arise then.)
 
rjh01 said:
The clouds on Venus are not water.



https://www.universetoday.com/36291/is-there-water-on-venus/

In other words Venus' atmosphere has 0.5% of the water of Earth's atmosphere.
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Here a few of the things I find interesting about this.

1. The researchers spent some time evaluating any possible natural sources for this phosphene. While volcanic activity can produce it, the problem is that it produces far lower levels of the chemical than has been found. If it was the source, then they would also expect to see massive levels of vulcanism on the planet.

2. The phosphene they have found tends to be in the temperate temperature range of the clouds. If it is from a natural source such as vulcanism, there is no known mechnanisn that would account for that. Volcanically produced phosphene would be evenly or randomly distributed.

If what has been found is actually phosphene, it is really difficult to account for its high levels and specific distribution pattern.
 
Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine

Context: ALMA observations of Venus at 267 GHz have been presented in the literature that show the apparent presence of phosphine (PH3) in its atmosphere. Phosphine has currently no evident production routes on the planet's surface or in its atmosphere.

Aims: The aim of this work is to assess the statistical reliability of the line detection by independent re-analysis of the ALMA data.

Methods: The ALMA data were reduced as in the published study, following the provided scripts. First the spectral analysis presented in the study was reproduced and assessed. Subsequently, the spectrum was statistically evaluated, including its dependence on selected ALMA baselines.

Results: We find that the 12th-order polynomial fit to the spectral passband utilised in the published study leads to spurious results. Following their recipe, five other >10 sigma lines can be produced in absorption or emission within 60 km/s from the PH3 1-0 transition frequency by suppressing the surrounding noise. Our independent analysis shows a feature near the PH3 frequency at a ~2 sigma level, below the common threshold for statistical significance. Since the spectral data have a non-Gaussian distribution, we consider a feature at such level as statistically unreliable that cannot be linked to a false positive probability.

Conclusions: We find that the published 267-GHz ALMA data provide no statistical evidence for phosphine in the atmosphere of Venus.
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So, maybe there's no phosphine there after all, in which case, no need to hypothesize how it might have been produced.
 
Puppycow said:
So, maybe there's no phosphine there after all, in which case, no need to hypothesize how it might have been produced.
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Oh well.

It is good, though, that the original team published the details of their analysis sufficient for others to replicate it and get the same results, even if that analysis wasn't sufficient. They may have been wrong, but at least they were only wrong, if you get my meaning.
 
New article in Nature:

Prospects for life on Venus fade — but aren’t dead yet

In September, an international team of astronomers made headlines when it reported finding phosphine — a potential marker of life — in the planet’s atmosphere1. Several studies questioning the observations and conclusions quickly followed. Now, the same team has reanalysed part of its data, citing a processing error in the original data set. The researchers confirmed the phosphine signal, but say that it’s fainter than before.
. . .

The reanalysis, based on radio-telescope observations at the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, concludes that average phosphine levels across Venus are about one part per billion — approximately one-seventh of the earlier estimate. Unlike in their original report, the scientists now describe their discovery of phosphine on Venus as tentative2.
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New study says that they may have just detected sulphur dioxide:

https://www.nature.com/articles/d41586-021-00249-y

But it's not game over yet:

Still, the case isn’t closed yet. The new studies argue against the presence of phosphine, but can’t entirely rule it out. “There’s enough wiggle room there,” says Meadows.

Ultimately, the debate can be resolved only with fresh observations of Venus, many of which are planned in the coming months and years, says Akins. “Until we see something new, it’s probably just going to keep going back and forth.
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Oh hell just send a damn probe up there. Class 5, preferably.
 
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