Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds

Mogul, Rakesh; Limaye, S. S.; Way, Michael; Hodges, R. R.

doi:10.1002/essoar.10504552.1

Cited by 5 publications

(6 citation statements)

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“…A fundamental requirement for life is a source of free energy [ 1 ]. Redox gradients may be available as energy sources in the clouds of Venus [ 110 ], but light to power photosynthesis is the most abundant energy source. We note that CSA is capable of supporting photochemical interconversion of other transition metal complexes (e.g., Re(VIII)/Re(VI) [ 111 , 112 ]).…”

Section: Discussionmentioning

confidence: 99%

Evaluating Alternatives to Water as Solvents for Life: The Example of Sulfuric Acid

Bains

Petkowski

Zhan

et al. 2021

Life

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The chemistry of life requires a solvent, which for life on Earth is water. Several alternative solvents have been suggested, but there is little quantitative analysis of their suitability as solvents for life. To support a novel (non-terrestrial) biochemistry, a solvent must be able to form a stable solution of a diverse set of small molecules and polymers, but must not dissolve all molecules. Here, we analyze the potential of concentrated sulfuric acid (CSA) as a solvent for biochemistry. As CSA is a highly effective solvent but a reactive substance, we focused our analysis on the stability of chemicals in sulfuric acid, using a model built from a database of kinetics of reaction of molecules with CSA. We consider the sulfuric acid clouds of Venus as a test case for this approach. The large majority of terrestrial biochemicals have half-lives of less than a second at any altitude in Venus’s clouds, but three sets of human-synthesized chemicals are more stable, with average half-lives of days to weeks at the conditions around 60 km altitude on Venus. We show that sufficient chemical structural and functional diversity may be available among those stable chemicals for life that uses concentrated sulfuric acid as a solvent to be plausible. However, analysis of meteoritic chemicals and possible abiotic synthetic paths suggests that postulated paths to the origin of life on Earth are unlikely to operate in CSA. We conclude that, contrary to expectation, sulfuric acid is an interesting candidate solvent for life, but further work is needed to identify a plausible route for life to originate in it.

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Section: Discussionmentioning

confidence: 99%

Evaluating Alternatives to Water as Solvents for Life: The Example of Sulfuric Acid

Bains

Petkowski

Zhan

et al. 2021

Life

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“…All the metabolisms required reduced species as input, either hydrogen-containing compounds (H 2 S or H 2 ) or carbon monoxide. Reduced compounds are predicted to be rare in Venus' oxidized atmosphere (e.g., Marcq et al, 2018), and the limited experimental data confirm this (e.g., Mogul et al, 2021b;, so it is not surprising that the chosen metabolisms could not explain the SO 2 depletion. Interestingly, Jordan et al found that the chemical energy available could support a biosphere within the mass ranges summarized in Table 1.…”

Section: Energymentioning

confidence: 99%

“…T he tentative detection of phosphine in the atmosphere of Venus (Bains et al, 2021b(Bains et al, , 2022aGreaves et al, 2021aGreaves et al, , 2021bGreaves et al, , 2021cGreaves et al, , 2022Mogul et al, 2021b) has re-ignited interest in the idea that life might exist in Venus' clouds. With that renewed interest have come a variety of suggestions that what we know about Venus inherently rules out the possibility of life, and consequently that investing effort in modeling or detecting Venusian life is a waste of resources at best, unscientific at worst (Cockell et al, 2021b).…”

Section: Introductionmentioning

confidence: 99%

Venus' Atmospheric Chemistry and Cloud Characteristics Are Compatible with Venusian Life

2024

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Venus is Earth's sister planet, with similar mass and density but an uninhabitably hot surface, an atmosphere with a water activity 50-100 times lower than anywhere on Earths' surface, and clouds believed to be made of concentrated sulfuric acid. These features have been taken to imply that the chances of finding life on Venus are vanishingly small, with several authors describing Venus' clouds as ''uninhabitable,'' and that apparent signs of life there must therefore be abiotic, or artefactual. In this article, we argue that although many features of Venus can rule out the possibility that Earth life could live there, none rule out the possibility of all life based on what we know of the physical principle of life on Earth. Specifically, there is abundant energy, the energy requirements for retaining water and capturing hydrogen atoms to build biomass are not excessive, defenses against sulfuric acid are conceivable and have terrestrial precedent, and the speculative possibility that life uses concentrated sulfuric acid as a solvent instead of water remains. Metals are likely to be available in limited supply, and the radiation environment is benign. The clouds can support a biomass that could readily be detectable by future astrobiology-focused space missions from its impact on the atmosphere. Although we consider the prospects for finding life on Venus to be speculative, they are not absent. The scientific reward from finding life in such an un-Earthlike environment justifies considering how observations and missions should be designed to be capable of detecting life if it is there.

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“…Especially insightful would be if a different methodology could be employed, such as trying to detect phosphine in the infrared range of the spectrum. An independent confirmation could also derive from a re-analysis of the Large Probe Neutral Mass Spectrometer (LNMS) on board of the Pioneer-Venus mission, as done by Mogul et al [ 52 ]. In their recently published paper, they claimed that their analysis is suggestive of PH 3 and H 2 S being present in the middle clouds, based on a peak fitting model that uses data points within the LNMS dataset to estimate the full-width half-maximum and peak heights of chemical reference and target species.…”

Section: The Claimed Detection Of Phosphinementioning

confidence: 99%

The Case (or Not) for Life in the Venusian Clouds

Schulze‐Makuch

2021

Life

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The possible detection of the biomarker of phosphine as reported by Greaves et al. in the Venusian atmosphere stirred much excitement in the astrobiology community. While many in the community are adamant that the environmental conditions in the Venusian atmosphere are too extreme for life to exist, others point to the claimed detection of a convincing biomarker, the conjecture that early Venus was doubtlessly habitable, and any Venusian life might have adapted by natural selection to the harsh conditions in the Venusian clouds after the surface became uninhabitable. Here, I first briefly characterize the environmental conditions in the lower Venusian atmosphere and outline what challenges a biosphere would face to thrive there, and how some of these obstacles for life could possibly have been overcome. Then, I discuss the significance of the possible detection of phosphine and what it means (and does not mean) and provide an assessment on whether life may exist in the temperate cloud layer of the Venusian atmosphere or not.

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Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds

Abstract: Venus' clouds harbor several proposed trace chemical species that suggest the potential for chemistries yet to be discovered. Exemplar trace species include ammonia, oxygen, hydrogen, methane, and ethene, which were detected remotely or in situ (

Cited by 5 publications

References 32 publications

Evaluating Alternatives to Water as Solvents for Life: The Example of Sulfuric Acid

Evaluating Alternatives to Water as Solvents for Life: The Example of Sulfuric Acid

Venus' Atmospheric Chemistry and Cloud Characteristics Are Compatible with Venusian Life

The Case (or Not) for Life in the Venusian Clouds

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