A new study identified 37 volcanic structures that were recently active in Venus. The study provides some of the best evidence to date that Venus is still a geologically active star. A research paper on the work, conducted by researchers at the University of Maryland and the Institute of Geophysics at ETH Zurich, Switzerland, was published in the journal Nature Geoscience on July 20, 2020.
“This is the first time we can point to specific structures and say, ‘Look, this is not an ancient volcano but one that is active today, perhaps dormant, but not dead,'” said Lauren Montsey, a professor of geology at the University of Maryland and co-author of the research paper. “This study significantly changes the opinion of Venus from a star that is mostly inactive to one whose face is still noisy and can feed many active volcanoes.”
Scientists have long known that Venus has a younger surface than stars like Mars and a hot star, whose faces are cold. Evidence of a hot face and geological activity dot the star’s surface in the form of ring-like structures called crowns, which are formed when strands of hot matter in the depths of the star rise through the crustal layer and crust. This is similar to how shell transformations formed the volcanic islands of Hawaii.
But it was thought that the crowns in Venus were probably signs of ancient activity, and Venus had cooled enough to slow down the geological activity inside the star and harden the crust to such an extent that any hot matter from the depths could not pierce out. In addition, the exact processes by which shell transformations created crowns in Venus and the reason for the differences between the crowns were a matter of debate.
In the new study, the researchers used numerical models of thermo-mechanical activity below Venus’ surface to create high-resolution three-dimensional simulations of crown formation. Their simulations provide a more detailed look than ever at the process.
The results helped Montsey and colleagues identify surface shapes that are only found in crowns that have been active recently. The team was able to match these shapes to the shapes observed on Venus’ surface, and discovered that some of the variability in the crowns on the planet represents different stages of geological development. The study provides the first proof that Venus crowns are still developing, an indication that the star’s face is still noisy.
“The improvement in the degree of realism in these models compared to previous studies makes it possible to identify several stages in the development of crowns and to define diagnostic geological forms that are found only in crowns that are currently active,” Montsey said. “We can say that at least 37 crowns have been very active recently.”
The active crowns in Venus are grouped in a few places, indicating areas where the star is most active, suggesting the mode of action of the star’s interior. These results may help identify target areas where geological instruments will be placed on future missions to Venus, such as the European EnVision whose launch is planned for 2032.
To the scientific paper
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