Mysterious missing component in the clouds of Venus revealed

On January 5, 2024 - This piece has been meticulously examined through Science X's stringent editorial procedures and policies. The editors underscored various facets ensuring the article's credibility including fact-checking, peer-reviewing, proofreading by Vanessa Bismuth from the University of Cambridge, and sourcing from trustworthy publications.

The clouds of Venus are primarily composed of sulfuric acid droplets, with small concentrations of water, chlorine, and iron, with their densities fluctuating with height in Venus' inhospitable atmosphere. However, scientists have been grappling to pin down on the missing elements that would shed light on the distinctive patches and streaks of the clouds that are only perceptible in the UV spectrum.

A recent study carried out by researchers from the University of Cambridge and published in Science Advances offered some insights into the mystery. The scientists developed iron-bearing sulfate minerals under laboratory conditions which were capable of surviving the caustic chemical conditions in Venus' atmosphere. Spectroscopic examination highlighted a blend of two minerals - rhomboclase and acid ferric sulfate which could solve the puzzle surrounding the unexpected UV absorption characteristics of our neighboring planet.

Paul Rimmer from the Cavendish Laboratory and co-author of the study noted, "Analyzing the data gathered from probes about the cloud composition indicated unusual properties that have baffled us. Especially, a peculiar UV absorption pattern has been noted in these clouds. The questions arise - which elements, compounds, or minerals are causing such effect?"

The synthesis of the iron-bearing sulfate minerals was based on the atmospheric chemistry of Venus and was conducted in an aqueous geochemistry lab within the Department of Earth Sciences. By observing the mineralogical and chemical changes that occurred while the synthesized substances were placed within varying concentrations of sulfuric acid, the researchers narrowed down the probable minerals to rhomboclase and acid ferric sulfate. Their spectroscopic characteristics were subsequently analyzed using light sources tailored to imitate the solar flare spectrum.

A photochemistry lab at Harvard University also collaborated in the study by furnishing UV absorbance patterns measurements of ferric iron under exceedingly acidic conditions, in an effort to replicate the even harsher environment of Venus' clouds.

Co-author Clancy Zhijian Jiang, from the Department of Earth Sciences, Cambridge, pointed out, "The patterns and absorption levels exhibited by the combination of these two mineral phases conform to the UV patches seen in the Venusian clouds. These experiments have helped us understand the complicated chemical network within the atmosphere and the elemental cycling on its surface.”

Rimmer added that Venus is yet shrouded in mystery despite being our closest neighbor, but hoped that upcoming ESA and NASA missions aimed at exploring its atmosphere, clouds, and surface would reveal more. This study lays the groundwork for these anticipated investigations.

More information can be found in the research paper titled 'Iron sulfur chemistry can explain the ultraviolet absorber in the clouds of Venus' published in Science Advances (2024). DOI: 10.1126/sciadv.adg8826. Journal information: Science Advances. The article information is brought to you by the University of Cambridge.