Radar images taken more than 30 years ago have just revealed the most conclusive evidence of an erupting volcano on Venus, Earth’s twin planet, which for unknown reasons has become a hellish world whose surface touches 500 degrees, enough to to melt lead.
In 1991, NASA’s Magellan probe — named after the navigator that Spain sent on the first circumnavigation expedition in the 16th century — mapped the planet’s surface with radar. Radio signals penetrated the thick clouds, revealing the orography in three dimensions. Mankind looked upon a planet dotted with volcanoes, though whether they were active or geological relics from the distant past was impossible to tell.
Magellan easily broke the record for information sent to Earth from another planet: 1,200 gigabytes, more than all previous missions combined. Today it seems like a ridiculous amount, but the truth is that some of the radar images were so heavy that it was not possible to analyze them in detail with conventional computers for a long time, explains Scott Hensley, a researcher at NASA’s Jet Propulsion Laboratory. A few years ago, this physicist began comparing images of Magellan taken in February and October 1991 in two consecutive overflights over the same location. The findings, now published in the journal Science, World Science Podium, provide the strongest evidence yet that Earth is not the only planet in the solar system with active volcanoes.
A radar view of Venus taken by the ‘Magellan’ mission.NASA
In the images from the first pass, the probe revealed a volcanic fissure about two square kilometers and 175 meters deep, like a 58-story skyscraper. When the spacecraft passed again eight months later, the rift had doubled in size and appeared to be filled to the brim with what scientists believe can only be lava. The molten rock would have covered an area of nearly 70 square meters, more or less twice the area covered by the 2018 eruption of Hawaii’s Kilauea volcano, the study notes.
Although it’s not “100 percent certain” that it was a volcanic eruption, since the observations were almost at the resolution limit of radar, the volcano is “the most plausible explanation,” says Hensley. The new eruption is taking place on the slopes of Maat Mons, the tallest volcano on Venus that was believed to be extinct.
Robert Herrick is a geophysicist at the University of Alaska at Fairbanks and a co-author of the study. “So far, there has been indirect evidence of volcanism on Venus,” he explains. “There is evidence of chemical reactions that indicate eruptions and other geological activity data, but it could not be known whether they happened thousands of years ago or are happening right now. Our work reveals a new volcanic structure that formed eight months into 1991 and is the most conclusive evidence of an eruption on the planet,” he points out.
With these tests, Venus would be the second planet in the solar system, next to Earth, with active volcanism. Adding to these two is Io, the moon of Jupiter, arguably the most active body in the entire solar system, where there are hundreds of volcanoes spewing lava fountains several kilometers high.
In December, the discovery of an active volcanic area on Mars, the size of all of Europe, which could erupt at any time, was announced. Finding volcanoes is always interesting, as these bodies create habitable environments for living beings, at least on Earth.
The planet Venus. Getty Images
The possibility of life on Venus is slim but not impossible. In September 2020, scientists from Europe and the US announced the discovery of phosphine, a chemical compound in the atmosphere that could be the first evidence of life on the planet. Since then, various teams have tried unsuccessfully to replicate this discovery, and the possibility that the planet is habitable has been discounted.
Iván López, a planetary geologist from the Rey Juan Carlos University in Madrid, is an expert in the geology of Venus and a member of the European Space Agency’s ExoMars mission. “Venus and Earth were born as twins,” he explains. “They’re practically the same size and composition. Venus can even have water. But something happened that created a brutal greenhouse effect. All experts on Venus believe that there are active volcanoes, but the truth is that there is no conclusive evidence for this yet. We know that this planet does not have plate tectonics like Earth. Understanding how plateless volcanism is possible can help us better understand an alternative mechanism of volcanism and even detail how tectonics formed on Earth, which is essential for its habitability,” he explains.
In 2031, the United States and Europe will launch two new missions to Venus to study both its dense atmosphere for life and its searing, orange surface. Working with both missions, Veritas and EnVision, respectively, Hensley and Herrick are developing the new radars that will remap the planet for volcanic activity.
On April 27, 1521, the navigator Ferdinand Magellan died fighting the natives of the island of Mactan (Philippines). Gipuzkoan Juan Sebastián Elcano took command of the expedition until returning it to Spain after completing the first orbit. The Magellan spacecraft was also somehow killed in battle. In October 1994, NASA engineers immersed it in the clouds of Venus until it dissipated. But their data could hide many more surprises, Herrick says: “The probe has covered up to 40 percent of the surface of Venus at least twice, and so far we’ve only analyzed 1.5 percent in detail.”
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