Scientists discover an active volcano on Venus for the first time

Earth and Venus have a lot in common. Both are rocky planets of roughly similar size, and Venus likely has an inner core and partially molten mantle. Cone-shaped mountains and solidified basalt flows indicate that there was also widespread volcanic activity on the planet’s surface at some time in the planet’s past.

But unlike Earth, which has over 1,000 active volcanoes, active volcanic processes have never been observed on Venus. Until now.

Scientists made the discovery after poring over archived radar images of Venus (Venus’ dense atmosphere makes direct observation impossible) taken more than 30 years ago, in the 1990s, by NASA’s Magellan mission. The images showed a volcanic vent changing shape and increasing significantly in size in less than a year.

Scientists study active volcanoes to understand how a planet’s interior can shape its crust, fuel its evolution and affect its habitability. One of NASA’s new missions to Venus will do just that. Run by the agency’s Jet Propulsion Laboratory in Southern California, VERITAS – short for Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy – will be on the market within a decade. The orbiter will study Venus from surface to core to understand how the planet evolved from a potentially habitable world to a hellish landscape covered in volcanic plains and deformed terrain buried beneath a thick, hot, toxic atmosphere are hidden.

“NASA’s selection for the VERITAS mission inspired me to look for recent volcanic activity in Magellanic data,” said Robert Herrick, research professor at the University of Alaska Fairbanks and a member of the VERITAS science team leading the search for the Archive data headed. “I didn’t really expect to be successful, but after about 200 hours of manually comparing images from different Magellanic orbits, I saw two images of the same region taken eight months apart, showing telltale geological changes caused by an eruption were caused.”

The geological changes Herrick found occurred in Atla Regio, a vast highland region near Venus’ equator that is home to two of the planet’s largest volcanoes, Ozza Mons and Maat Mons. The region has long been thought to be volcanically active, but there has been no direct evidence of recent activity.

While examining Magellanic radar images, Herrick identified a volcanic vent associated with Maat Mons that changed significantly between February and October 1991.

In the February image, the vent appeared nearly circular, covering an area of ​​less than 2.2 square kilometers. It had steep interiors and showed signs of drained lava on its outer slopes, factors indicative of activity. In radar images taken eight months later, the same aperture had doubled and become misshapen. It also appeared to be filled to the brim with a lava lake.

However, since the two observations were made from opposite vantage points, they had different perspectives, making comparison difficult. The low resolution of the three-decade-old data only made the work more complicated.

Herrick teamed up with JPL’s Scott Hensley, the project scientist for VERITAS and a specialist in analyzing radar data like Magellan’s. The two researchers created computer models of the vent in different configurations to test different geological event scenarios such as landslides. From these models, they concluded that only an eruption could have caused the change.

“Only a few of the simulations matched the images, and the most likely scenario is that volcanic activity took place on the surface of Venus during Magellan’s mission,” Hensley said. “Although this is only one data point for an entire planet, it confirms that there is modern geological activity.”

Scientists compare the size of the lava flow produced by Maat Mons activity to the 2018 Kilauea eruption on the Big Island of Hawaii.

The search and its conclusions are detailed in a new study published in the journal Science. Herrick also presented the findings at the 54th Lunar and Planetary Science Conference in Woodlands, Texas on March 15.

Herrick, Hensley and the rest of the VERITAS team are excited to see how the mission’s suite of advanced scientific instruments and high-resolution data will complement Magellan’s remarkable trove of radar images that have transformed mankind’s knowledge of Venus.

“Venus is an enigmatic world, and Magellan has shown so many possibilities,” said Jennifer Whitten, VERITAS associate deputy principal investigator at Tulane University in New Orleans. “Now that we are very confident that the planet experienced a volcanic eruption just 30 years ago, this is a small preview of the incredible discoveries VERITAS will make.”

VERITAS will use state-of-the-art synthetic aperture radar to create 3D global maps and a near-infrared spectrometer to find out what the surface is made of. The spacecraft will also measure the planet’s gravitational field to determine the structure of Venus’ interior. Together, the instruments will provide clues to the planet’s past and present geological processes.

And while Magellan’s data were initially cumbersome to study — Herrick said they relied in the 1990s on boxes of CDs of Venus data compiled by NASA and shipped in the mail — VERITAS’ data will be available online to the scientific community . This will allow researchers to apply cutting-edge techniques like machine learning to analyze the planet and help unveil its innermost secrets.

These studies will be complemented by EnVision, an ESA (European Space Agency) mission to Venus, scheduled for launch in the early 2030s. The spacecraft will carry its own synthetic aperture radar (called VenSAR), which is being developed at JPL, and a spectrometer similar to the one VERITAS will carry. Both Hensley and Herrick are key members of the VenSAR science team.

Material provided by NASA/JPL-Caltech

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