Phosphine, a strong biosignature, has been detected in the atmosphere of Venus

[Selfsim]

Earth life has surprised us in this regard before, showing up in places where we thought it couldn't possibly survive. Extremophiles, life that harvests energy in uncommon ways, we didn't know until we found them.

Earth-life has evolved alongside an (evidenced) abundant, ubiquitous water supply, whereas Venus' hypothesised water analogy is purely model dependent.
Water facilitates life's evolvability (and adaption), so the argument that speculated Venusian life evolved and adapted to present-day conditions, is also purely model dependent and lacking in an accurate (objective) Venusian context.

Let's go find out what's really there. Design and send probes that actually examine in detail the atmosphere at the level where phosphene was found.

'Unknown' is the accurate (and honest) basis for initiating such investigatory missions.
Venusian life-searching missions however, are based on pure speculation.

[Noclevername]

Earth-life has evolved alongside an (evidenced) abundant, ubiquitous water supply, whereas Venus' hypothesised water analogy is purely model dependent.
Water facilitates life's evolvability (and adaption), so the argument that speculated Venusian life evolved and adapted to present-day conditions, is also purely model dependent and lacking in an accurate (objective) Venusian context.

'Unknown' is the accurate (and honest) basis for initiating such investigatory missions.
Venusian life-searching missions however, are based on pure speculation.

Tests designed to find out if there is life, are honestly a good basis for a probe. The results of those tests, will give us something to talk about. Until then it's all speculation. Including your conclusions.

[Colin Robinson]

Sigh ..

No need for me withdraw anything, as what I said was: there is (now) evidence of its implausibility .. not the least of which is:

(i) the decreased levels of phosphine subsequently announced by Greaves etal, due to the original errored (uncalibrated?) raw data (now down to only several ppb),
(ii) the exothermic nature of the 2SO₃ + 4H₂O → 2H₂SO₄+ H₂O. reaction and its effect on any active biochemistry and;
(iii) the known highly corrosive effects of H₂SO₄ on organic matter.

H₂SO₄ is destructive to some organic compounds, but by no means to all of them. As the eminent chemist Ronald J. Gillespie observed back in 1959: "anhydrous sulfuric acid... is a good solvent for a wide variety of organic compounds, very many of which give stable solutions, from which they may be recovered unchanged".

[Selfsim]

Tests designed to find out if there is life, are honestly a good basis for a probe.

In the case of Venus, please cite the specific probe tests which would permit constraining a conclusion to 'life' or 'no life'.

Until then it's all speculation. Including your conclusions.

Which conclusions do you refer to there, specifically?

[Selfsim]

H₂SO₄ is destructive to some organic compounds, but by no means to all of them. As the eminent chemist Ronald J. Gillespie observed back in 1959: "anhydrous sulfuric acid... is a good solvent for a wide variety of organic compounds, very many of which give stable solutions, from which they may be recovered unchanged".

Can you please list the plausible bio-active organic compounds?

[Colin Robinson]

Can you please list the plausible bio-active organic compounds?

I won't attempt to list all of them, but here are three categories for a start:

1. Compounds containing oxidised sulfur

Carbon chains linked to the sulfate (SO₄) functional group, a fragment of the sulfuric acid molecule, are known as organosulfates or sulfate esters. They are analogous to carbohydrates, which contain fragments of the water molecule. But compared to carbohydrates, organosulfates are weaker bases and stronger acids, and therefore more likely to occur in an acidic environment.

Sulfonic acids and sulfonates are a related class of compounds with one less oxygen atom in each functional group. Organosulfates and sulfonates are found in soils here on Earth, and play a part in sulfur cycling. The sulfonic acid taurine is present in the bodies of all living things with complex cells (eukaryotes), including us humans.

2. Compounds with alkene bonds

The alkene group consists of two carbon atoms with a double bond (C=C). In sulfuric acid solution, the alkene group behaves similarly to the carbonyl (C=O) group in water solution, enabling synthesis of long chains of carbon atoms out of shorter chains. (See The Limits of Organic Life in Planetary Systems, National Research Council, Washington 2007. Chapter 6, Section 6.2.1.2)

3. Carbon chains which also include silicon atoms

Carbon chain compounds which incorporate silicon atoms in the chain are well known to chemists. However, they are unstable in water, and are seldom if ever used by Earth life. As Janusz Petkowski, William Bains and Sara Seager recently found, these compounds are more stable in sulfuric acid, and have properties which could be useful for life, such as enabling movement of electrons along the chain.

[Selfsim]

.. here are three categories for a start

Noted that you shifted to generalised compound categories, rather than the more specific and narrowly focused bio-active compounds in my original query.

1. Compounds containing oxidised sulfur
..
The sulfonic acid taurine is present in the bodies of all living things with complex cells

Taurine is biosynthesized by the enzymatic modification of proteins following protein biosynthesis. It is also a product of the transsulfuration metabolic pathway.

So, how can the protein biosynthesis and metabolic bio-active precursor processes, needed by life to produce such sulfonic acids, plausibly function in Venus’ concentrated atmospheric sulfuric acid (given that such precursor processes rely on the presence of water -ie: cytoplasm’s key constituent)?

2. Compounds with alkene bonds

These are more generalised classes of organic molecules and not the more specific bio-active compounds specified in my original query.
This is akin to an organic chemistry ‘algebra error’ to me, unfortunately(?)

3. Carbon chains which also include silicon atoms

It seems you are attempting to manufacture a life-as-we-don’t-know-it (LAWDKI) solution .. which is ok .. but when discussing the evidence of plausibility, LAWDKI explanations tend to produce a major plausibility nose-dive in comparison with non-life explanations for Venus’ reported trace levels of atmospheric phosphine.

[Colin Robinson]

Noted that you shifted to generalised compound categories, rather than the more specific and narrowly focused bio-active compounds in my original query.

You want me to list every individual compound which could be "bio-active"?

Why aren't generalised compound categories enough to back up the general idea that something may be growing and reproducing in Venus' clouds?

Taurine is biosynthesized by the enzymatic modification of proteins following protein biosynthesis. It is also a product of the transsulfuration metabolic pathway.

So, how can the protein biosynthesis and metabolic bio-active precursor processes, needed by life to produce such sulfonic acids, plausibly function in Venus’ concentrated atmospheric sulfuric acid (given that such precursor processes rely on the presence of water -ie: cytoplasm’s key constituent)?

Sounds like you don't just want a list of specific compounds, you also want a complete metabolic path to get to each compound...

It seems you are attempting to manufacture a life-as-we-don’t-know-it (LAWDKI) solution ..

The clouds of Venus contain H₂SO₄ at concentrations which occur on Earth only in artificial situations, e.g. chemical laboratories. If something is growing and reproducing there, I'd expect it to be chemically somewhat different from life on Earth.

which is ok .. but when discussing the evidence of plausibility, LAWDKI explanations tend to produce a major plausibility nose-dive in comparison with non-life explanations for Venus’ reported trace levels of atmospheric phosphine.

What are your non-life explanations for Venus' reported phosphine?

[Noclevername]

In the case of Venus, please cite the specific probe tests which would permit constraining a conclusion to 'life' or 'no life'.

Which conclusions do you refer to there, specifically?

As already addressed, I cannot design tests. It's a strawman to put the burden of doing so on an amateur.

And you always draw the same conclusion in these LIS threads, so if you don't know what that is, it may entail some self-reflection.

[Van Rijn]

As already addressed, I cannot design tests. It's a strawman to put the burden of doing so on an amateur.

And in years past we have discussed the limitations of present technology life tests on probes, like those on, for instance, the Viking Mars landers. Given mass limits and complexity, it is possible to do certain specific tests, but it isn’t like a general laboratory where many things can be tested as different research routes are suggested. That’s why sample return becomes important. Alternatively, there could be a series of experiments on different probes done over a period of years, depending on prior experimental results. In either case, it is unreasonable to ask for a specific probe test. I wouldn’t expect subject matter experts to answer such a leading question.

And you always draw the same conclusion in these LIS threads, so if you don't know what that is, it may entail some self-reflection.

Yes, and absolute negativity when discussing questions like these is as unscientific as absolute positivity. Whether there is life or not in the Venusian atmosphere, it isn’t going to be determined on a discussion board.

[Roger E. Moore]

Two papers stating that it was not phosphine that was detected in Venus's atmosphere, but sulfur dioxide. Read on.

---

Claimed detection of PH3 in the clouds of Venus is consistent with mesospheric SO2

Andrew P. Lincowski, Victoria S. Meadows, David Crisp, Alex B. Akins, Edward W. Schwieterman, Giada N. Arney, Michael L. Wong, Paul G. Steffes, M. Niki Parenteau, Shawn Domagal-Goldman

The observation of a 266.94 GHz feature in the Venus spectrum has been attributed to PH3 in the Venus clouds, suggesting unexpected geological, chemical or even biological processes. Since both PH3 and SO2 are spectrally active near 266.94 GHz, the contribution to this line from SO2 must be determined before it can be attributed, in whole or part, to PH3. An undetected SO2 reference line, interpreted as an unexpectedly low SO2 abundance, suggested that the 266.94 GHz feature could be attributed primarily to PH3. However, the low SO2 and the inference that PH3 was in the cloud deck posed an apparent contradiction. Here we use a radiative transfer model to analyze the PH3 discovery, and explore the detectability of different vertical distributions of PH3 and SO2. We find that the 266.94 GHz line does not originate in the clouds, but above 80 km in the Venus mesosphere. This level of line formation is inconsistent with chemical modeling that assumes generation of PH3 in the Venus clouds. Given the extremely short chemical lifetime of PH3 in the Venus mesosphere, an implausibly high source flux would be needed to maintain the observed value of 20±10 ppb. We find that typical Venus SO2 vertical distributions and abundances fit the JCMT 266.94 GHz feature, and the resulting SO2 reference line at 267.54 GHz would have remained undetectable in the ALMA data due to line dilution. We conclude that nominal mesospheric SO2 is a more plausible explanation for the JCMT and ALMA data than PH3.

https://arxiv.org/abs/2101.09837

========

Complications in the ALMA Detection of Phosphine at Venus

Alex B. Akins, Andrew P. Lincowski, Victoria S. Meadows, Paul G. Steffes

Recently published ALMA observations suggest the presence of 20 ppb PH3 in the upper clouds of Venus. This is an unexpected result, as PH3 does not have a readily apparent source and should be rapidly photochemically destroyed according to our current understanding of Venus atmospheric chemistry. While the reported PH3 spectral line at 266.94 GHz is nearly co-located with an SO2 spectral line, the non-detection of stronger SO2 lines in the wideband ALMA data is used to rule out SO2 as the origin of the feature. We present a reassessment of wideband and narrowband datasets derived from these ALMA observations. The ALMA observations are re-reduced following both the initial and revised calibration procedures discussed by the authors of the original study. We also investigate the phenomenon of apparent spectral line dilution over varying spatial scales resulting from the ALMA antenna configuration. A 266.94 GHz spectral feature is apparent in the narrowband data using the initial calibration procedures, but this same feature can not be identified following calibration revisions. The feature is also not reproduced in the wideband data. While the SO2 spectral line is not observed at 257.54 GHz in the ALMA wideband data, our dilution simulations suggest that SO2 abundances greater than the previously suggested 10 ppb limit would also not be detected by ALMA. Additional millimeter, sub-millimeter, and infrared observations of Venus should be undertaken to further investigate the possibility of PH3 in the Venus atmosphere.

https://arxiv.org/abs/2101.09831

[cannongray]

The discovered substance - phosphine (phosphorus hydride, PH₃) - is a colorless poisonous gas that is extremely rare in natural conditions. On Earth, it is mainly obtained artificially - as a result of a chemical reaction in production. Phosphine is also released during lightning strikes and as a result of volcanic activity, but only in very small quantities, and significant reserves of this gas have been found on Venus. So I don't believe it means there could be similar life on Venus as on the Earth.

[Roger E. Moore]

Purported phosphine on Venus more likely to be ordinary sulfur dioxide, new study shows (as previously reported here). "Instead of phosphine in the clouds of Venus, the data are consistent with an alternative hypothesis: They were detecting sulfur dioxide," said co-author Victoria Meadows, a UW professor of astronomy. "Sulfur dioxide is the third-most-common chemical compound in Venus' atmosphere, and it is not considered a sign of life."

https://phys.org/news/2021-01-purpor...ry-sulfur.html

[Selfsim]

So we can put to rest (due to a lack of evidence): the 'likelihood' of both life-as-we-do and life-as-we-don't know it .. in Venus' mesosphere?

[Noclevername]

So we can put to rest (due to a lack of evidence): the 'likelihood' of both life-as-we-do and life-as-we-don't know it .. in Venus' mesosphere?

Life as we know it, yes.

The point of life as we don't know it is that we don't know it. It seems unlikely as things stand; there's nothing we've seen that can't be accounted for by nonbiological processes.

I am however, a bit sad that the lack of phosphine means that Venus probes will probably not happen anytime soon.

[Colin Robinson]

Life as we know it, yes.

The point of life as we don't know it is that we don't know it. It seems unlikely as things stand; there's nothing we've seen that can't be accounted for by nonbiological processes.

I am however, a bit sad that the lack of phosphine means that Venus probes will probably not happen anytime soon.

Perhaps there’s a risk of jumping to negative conclusions here. One of the just-quoted papers actually calls for further research to determine whether Venus has phosphine or not.

Two papers stating that it was not phosphine that was detected in Venus's atmosphere, but sulfur dioxide. Read on.

Complications in the ALMA Detection of Phosphine at Venus

Alex B. Akins, Andrew P. Lincowski, Victoria S. Meadows, Paul G. Steffes

Recently published ALMA observations suggest the presence of 20 ppb PH3 in the upper clouds of Venus. This is an unexpected result, as PH3 does not have a readily apparent source and should be rapidly photochemically destroyed according to our current understanding of Venus atmospheric chemistry. While the reported PH3 spectral line at 266.94 GHz is nearly co-located with an SO2 spectral line, the non-detection of stronger SO2 lines in the wideband ALMA data is used to rule out SO2 as the origin of the feature. We present a reassessment of wideband and narrowband datasets derived from these ALMA observations... While the SO2 spectral line is not observed at 257.54 GHz in the ALMA wideband data, our dilution simulations suggest that SO2 abundances greater than the previously suggested 10 ppb limit would also not be detected by ALMA. Additional millimeter, sub-millimeter, and infrared observations of Venus should be undertaken to further investigate the possibility of PH3 in the Venus atmosphere. [emphasis added]

https://arxiv.org/abs/2101.09831

In any case, the report about phosphine is not the only reason for suspecting presence of life in the atmosphere of Venus...

A comment by planetary scientist and astrobiologist David Grinspoon, in October last year…

“It’s important to realize that, before this discovery, there was already renewed momentum for Venus and for good reasons. Possible biology in the clouds was already one of those reasons being considered.
There are many other reasons in terms of just trying to understand the history of a nearby Earthlike planet and the relevance for exoplanets. That momentum is deeper and longer-lived than just this discovery … which is a good thing because this discovery could go away.”

[Colin Robinson]

The discovered substance - phosphine (phosphorus hydride, PH₃) - is a colorless poisonous gas that is extremely rare in natural conditions. On Earth, it is mainly obtained artificially - as a result of a chemical reaction in production. Phosphine is also released during lightning strikes and as a result of volcanic activity, but only in very small quantities, and significant reserves of this gas have been found on Venus. So I don't believe it means there could be similar life on Venus as on the Earth.

Phosphine is also produced on Earth by microbial activity in environments with little free oxygen (O₂). That's why scientists have started a project looking for signs of the compound on other rocky planets. Venus was the first planet they looked at, basically because it is close to Earth and therefore easy to study, but the plan was to look for it in the atmospheres of exoplanets as well.

[Selfsim]

Phosphine is also produced on Earth by microbial activity in environments with little free oxygen (O₂)Venus was the first planet they looked at, basically because it is close to Earth and therefore easy to study, but the plan was to look for it in the atmospheres of exoplanets as well.

I cannot see where a plan (or method) which specifically seeks finding 'a something', which exhibits no evidence of its presence, within observational constraints, differs from the method used in the Hunt for the Holy Grail.

Such 'hunts' are known to lead to pseudoscience and sometimes even conspiracy theories.

The case of the hunt for atmospheric Venusian phosphine, now demonstrates the flaws in this method.

[Selfsim]

There are many other reasons in terms of just trying to understand the history of a nearby Earthlike planet and the relevance for exoplanets. That momentum is deeper and longer-lived than just this discovery … which is a good thing because this discovery could go away.”

What 'discovery'?

[Colin Robinson]

There are many other reasons in terms of just trying to understand the history of a nearby Earthlike planet and the relevance for exoplanets. That momentum is deeper and longer-lived than just this discovery … which is a good thing because this discovery could go away.”

The words you've quoted are actually by David Grinspoon.

What 'discovery'?

If you're not sure what he meant, I suggest you read the interview with him in SpaceNews. There's a link to it in my earlier message (#106).

[Noclevername]

I cannot see where a plan (or method) which specifically seeks finding 'a something', which exhibits no evidence of its presence, within observational constraints, differs from the method used in the Hunt for the Holy Grail.

Such 'hunts' are known to lead to pseudoscience and sometimes even conspiracy theories.

The case of the hunt for atmospheric Venusian phosphine, now demonstrates the flaws in this method.

It's not a "hunt" for phosphine, it's testing to find out IF there's any. It's a crucial, vital distinction.

[Selfsim]

The words you've quoted are actually by David Grinspoon.

And so? ..(That makes zero difference).

If you're not sure what he meant, I suggest you read the interview with him in SpaceNews. There's a link to it in my earlier message (#106).

The 'discovery' you quoted, which Grinspoon was referring to, was no 'discovery' at all. That's what I meant.

The context of, (and hence 'plausibility' of), Grinspoon's 'possible biology in the clouds' shifted with the sulphur dioxide explanation:

We conclude that nominal mesospheric SO2 is a more plausible explanation for the JCMT and ALMA data than PH3.

[Selfsim]

It's not a "hunt" for phosphine, it's testing to find out IF there's any.

That's not what Greaves said was the goal in the original paper:

Measurements of trace gases in planetary atmospheres help us explore chemical conditions different to those on Earth.

It's a crucial, vital distinction.

Not at all .. especially as that distinction made zero impact on the outcome.
In fact, if anything, it was a huge and completely irrelevant distraction.

[Colin Robinson]

The context of, (and hence 'plausibility' of), Grinspoon's 'possible biology in the clouds' shifted with the sulphur dioxide explanation:

We conclude that nominal mesospheric SO2 is a more plausible explanation for the JCMT and ALMA data than PH3.

And how do you know this sulphur dioxide explanation is right?

You're quoting from a paper which was "submitted on 25 Jan 2021". That means it has been presented for peer review, but the peer review process hasn't happened yet.

Why do you assume that this paper has got it right, and that the paper which presented the finding about phosphine has got it wrong?

[Noclevername]

Not at all .. especially as that distinction made zero impact on the outcome.
In fact, if anything, it was a huge and completely irrelevant distraction.

Sorry to hear you feel that way.

[Roger E. Moore]

UPDATES: Phosphineless Venus and dustless Betelgeuse? The <tl;dr> versions of both are: Venusian phosphine may have actually been sulfur dioxide, and Betelgeuse dimming may have been from it getting cooler.

https://www.syfy.com/syfywire/update...ess-betelgeuse