New research challenges the long-held belief that Venus is a geologically dead world, suggesting instead that the planet may still be experiencing active volcanism and tectonic activity. A study led by researchers at ETH Zurich, published in Nature Geoscience, used sophisticated three-dimensional simulations to analyze the formation of rift valleys on Venus, revealing that these features are likely much younger than previously thought.
Venus, the second planet from the Sun, is an extreme and inhospitable world. It has no oceans, is shrouded in a dense carbon dioxide atmosphere with clouds of sulfuric acid, and has surface temperatures reaching several hundred degrees Celsius. For years, scientists assumed that the planet's geological activity had ceased long ago, but the new findings point to a different reality.
The study focuses on the large scars that cross the planet's surface: rift valleys, which are immense systems of fractures and depressions in the Venusian crust. These features are among the main manifestations of tectonic activity on the planet. On Earth, rift valleys form when the lithosphere, the outer rigid layer of the planet, is subjected to extension due to plate tectonics, causing the crust to stretch, thin, and eventually fracture. The most emblematic example of such structures is the East African Rift System.
On Venus, however, there is no global system of moving plates. Instead, these rifts develop within a single rocky shell, likely in response to deep movements in the mantle, giving rise to large linear depressions that can reach up to ten thousand kilometers in length. Until now, the age of these structures has been the subject of intense debate among planetary geologists. The prevailing hypothesis held that the Venusian rifts formed more than a hundred million years ago and represented the vestiges of geological activity that had long since ended.
The research team overturns this interpretation, demonstrating that these structures actually formed recently, with some still evolving. The 3D simulations suggest that the rifts are geologically young, indicating ongoing internal activity. This finding has significant implications for understanding the geological history of Venus and its potential for current volcanic eruptions.
Piero D'Incecco, an expert in planetary geology at the INAF Abruzzo Observatory who was not involved in the study, explained the significance of the research. D'Incecco is the coordinator of the Avengers project, dedicated to analyzing recent volcanism on Venus through the study of terrestrial analogs, and a member of the Steering Committee of NASA's Venus Exploration Analysis Group (VEXAG). He noted that the new simulations provide strong evidence that Venus is far from being a dormant world.
The study adds to a growing body of evidence that challenges the traditional view of Venus as a geologically inactive planet. In recent years, multiple studies have progressively questioned this vision, with data from NASA's Magellan mission and other observations hinting at possible volcanic activity. The new research provides a more detailed mechanism for how this activity might occur, even in the absence of plate tectonics.
Understanding Venus's geological activity is crucial for planetary science. It offers insights into how terrestrial planets evolve and why Earth and Venus, despite similar sizes and compositions, followed such different paths. While Earth has active plate tectonics and a dynamic surface, Venus appears to have a different style of geological activity, one that may involve episodic resurfacing events and ongoing mantle convection.
The findings also have implications for future missions to Venus. NASA and the European Space Agency have several missions planned for the next decade, including NASA's VERITAS and DAVINCI missions, and ESA's EnVision. These missions will carry advanced instruments to map the planet's surface and study its geology in unprecedented detail. The new research provides a compelling target for these missions, as they can look for direct evidence of active volcanism and tectonic processes.
The study's results underscore that Venus remains a dynamic and mysterious world, with much still to be discovered. As scientists continue to analyze data from past missions and prepare for new ones, the picture of Venus as a geologically active planet is becoming increasingly clear, reshaping our understanding of the solar system's inner planets.
