For about half a century, scientists could only hope that one day they would see volcanoes erupt on Venus.

This hot neighbor world is shrouded in dangerous clouds, but previous missions have revealed volcanic features on its surface. Now, thanks to data from a defunct spacecraft, scientists have found evidence that there is a physical structure on Venus that is changing shape, expanding and appearing to be overflowing with molten rock.

“I bet it’s a lava lake eruption,” says Robert Herrick, a planetary scientist at the University of Alaska and one of two authors of the new study. According to a study published in the journal Science, Herrick and his colleague identified a volcanic “vent” on the flank of the colossal Maat Mons volcano from radar images taken by NASA’s Magellan spacecraft in 1991.

“This is one of the most compelling evidence we’ve seen,” confirms Steven Cain, a planetary astrophysicist at the University of California, Riverside, who was not involved in the work.

“The results stunned the scientific community,” says National Geographic. Experts expected to detect volcanic eruptions on Venus, but not before sending two spacecraft with advanced radar systems that permeate clouds – NASA VERITAS and Europa EnVision – in the early 2030s.

Keys to current volcanic activity are considered valuable as the second planet from the Sun is very similar to Earth in size and composition. Important water supplies that existed in the past – possible oceans – evaporated long ago “when the planet burned down in a mysterious cataclysm,” writes National Geographic. The most likely cause remains “uncontrolled climate change caused by explosions of apocalyptic proportions.” By understanding Venus’s current volcanic activity, scientists can learn more about the Earth’s diverging paths and the burning world that looks like it.

“If you want to understand the only other Earth-sized world we’ll ever go to, anywhere in the universe, Venus is the only option you have,” says Paul Byrne, a planetary scientist at the University of Washington in St. Luis, who was not involved in the new study.

Hidden “hell”

The opaque atmosphere of Venus hides the planet’s surface from observatories on Earth. Few spacecraft have approached the strange landscape, either by diving into the clouds and surviving no more than an hour or two before crashing into the hot surface, or by orbiting the planet by “looking” under the clouds using technologies such as radar.

A swarm of Soviet spacecraft in the early 1980s showed that Venus was almost completely covered in volcanic structures – some of them were similar to Earth, while others were clearly aliens. Hoping to map the planet’s features in unprecedented detail for the time, NASA’s Magellan spacecraft arrived in 1990 with radar instruments.

Repeatedly flying around the planet and several times exploring the same places, scientists hoped to find signs of volcanic activity. But there were problems. The low resolution of the radar meant that any physical changes had to be large enough to be captured on images. And from the very beginning of the mission, Magellan’s orbit narrowed with each revolution, causing the spacecraft to display less and less surface on each successive flight around the planet.

Despite the difficulties, 43% of the planet has been scanned at least twice. But comparing multiple images of the same volcano to look for changes also proved problematic because the angle of each image varied across multiple regions. In the following decades, no one managed to find an active volcano.

“Funnel” that transforms

Scientists have noted many indirect signs of active volcanic activity on Venus, including high concentrations of gases in the atmosphere associated with volcanic eruptions, new “suspicious” spots, and unusual features in colossal circular structures called coronas, which suggest underlying turbulence on a magmatic planet. .

But the “holy grail”—a lava-spewing volcano or a flowing river of molten rock—remained elusive.