New Evidence Suggests Tectonic Activity on Venus

Recent research has uncovered evidence indicating tectonic activity on Venus, utilizing data collected over 30 years ago. The findings, derived from the Magellan spacecraft's data, challenge longstanding beliefs about the planet's geological behavior.

Traditionally, Venus was thought to be devoid of tectonic processes; however, a study published in Science Advances reveals that the planet's surface is continuously reshaped, albeit through mechanisms distinct from Earth's plate tectonics.

The research team, led by scientists at the University of Bern, focused on geological formations known as 'coronae.' These circular structures can span from several tens to hundreds of kilometers in diameter, with approximately 740 identified on the planet.

The largest corona examined measures around 2,500 kilometers across. The researchers concentrated on the 75 most significant coronae, which were the only ones providing sufficiently detailed gravitational data for thorough investigation. The findings suggest that these formations arise in regions where the planetary crust is particularly thin, allowing for the upward movement of hot mantle material, which distorts the crust.

In around two-thirds of the coronae studied, researchers detected anomalies in the planet's gravitational field. These anomalies, recorded by Magellan, imply variations in the lithosphere's density and correlate with thermal plumes of hot material rising beneath the crust.

According to the research simulations, the process begins with heating of internal materials within Venus. The heated substance rises through the mantle, creating a plume beneath the coronae, leading to a dynamic tectonic environment that shapes their unique forms.

As the material ascends, it partially melts near the surface, causing the corona to bulge and expand radially. This outward pressure can result in the formation of mountain rings around the corona. Similar to terrestrial plate tectonics, the cooler crust may subduct beneath the warmer mantle, causing faults and depressions that typically encircle a corona.

The implications of these findings extend beyond Venus, offering insights into the early geological history of Earth. While coronae do not exist on Earth today, they may have been present during the planet's formative years before the establishment of modern plate tectonics. This research combines gravitational and topographical data to provide a fresh perspective on the subterranean processes currently shaping Venus's surface.

The Magellan spacecraft, which launched on May 4, 1989, mapped Venus's surface using radar technology capable of penetrating the planet's dense atmosphere. After years of orbiting the planet, Magellan re-entered Venus's atmosphere on October 12, 1994.

To further explore the coronae, researchers require higher-resolution data, which is expected to be available in the coming years. The European Space Agency's EnVision mission and NASA's VERITAS mission are slated to launch in the early 2030s, both of which aim to gather detailed gravitational data about Venus.