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Venus and Earth are often called sister planets due to similarities in size, mass, density and volume. A study looking into decades-old radar images has presented new evidence to indicate they have another feature in common: Active volcanoes.
A 2.2 square kilometre volcanic vent on Venus changed shape in eight months, indicating volcanic activity, the new study published in journal Science highlighted. A volcanic vent is a spot through which molten rock erupts. Comparison showed the vent almost doubled to a 4 sq km blob.
“After about 200 hours of manually comparing the images of different Magellan orbits, I saw two images of the same region taken eight months apart exhibiting telltale geological changes caused by an eruption,” Robert Herrick, a research professor at the University of Alaska Fairbanks, said in a statement.
Though Venus has over 1,600 major volcanoes, none were assumed to be active. Previous studies have found evidence of possible ongoing volcanic activities, which are still being debated.
Research from the University of Alaska Fairbanks, and Jet Propulsion Laboratory, California Institute of Technology analysed radar images generated by United States National Aeronautics and Space Administration’s Magellan mission to Venus. The spacecraft operated from May 4, 1989, to October 13, 1994.
Radar imaging uses radio wavelengths to take images of the surface. Magellan used radar to image Venus’ surface from different orbits. A few locations, including those suspected to have volcanic activity, were observed two or three times over two years.
Altitude data for the Maat and Ozza Mons region on the Venus surface is shown at left, with the area of study indicated by the black box. At right are the before (A) and after (B) Magellan observations of the expanded vent on Maat Mons, with possible new lava flows after an eruptive event. Credit: Robert Herrick/UAF
Overall, roughly 42 per cent of the global surface area was imaged two or more times, according to the researchers. They analysed images from 1990-1992 for changes in geologic features between two imaging cycles.
In the first image, the vent appeared nearly circular. It showed signs of drained lava, hinting at activity, the study noted. Eight months later, radar images indicated that the same vent had doubled in size and the lava lake seemed to have reached the rim.
The vent is associated with Maat Mons, the planet’s second-highest volcano. It sits in the Atla Regio, a vast highland region near Venus’ equator. These changes were likely due to lava flow escaping the vent, hinting at a possible volcanic activity.
“The changed vent is located in a region where volcanic activity was thought to be most likely,” the researchers wrote in their study.
However, the researchers speculate that Venus is less volcanically active than Jupiter’s moon Io, home to over 100 active spots. A 2021 study found clues to indicate recent volcanic activity in Idunn Mons, a Venusian volcanic peak in southern Venus.
Three missions are being planned to Venus: NASA’s VERITAS and DAVINCI and European Space Agency’s EnVision are expected to observe our neighbour in the 2030s.
“Venus is an enigmatic world and Magellan teased so many possibilities,” Jennifer Whitten, associate deputy principal investigator of VERITAS at Tulane University in New Orleans, said in a statement.
“Now that we’re very sure the planet experienced a volcanic eruption only 30 years ago, this is a small preview for the incredible discoveries VERITAS will make,” Whitten said.
The Indian Space Research Organisation, too, is working on Shukrayaan-1 to study Venus. The orbiter will likely study the planet’s geological and volcanic activity, emissions on the ground, wind speed, cloud cover, and other planetary characteristics from an elliptical orbit, according to the daily The Hindu.