(CNN) When scientists recently took a closer look at archival images of the surface of Venus, they discovered something new: evidence of volcanic activity on Earth’s “twin”.
NASA’s Magellan spacecraft took the pictures in the early 1990s when it was orbiting our nearest planet, which is similar to Earth in size and composition.
A new analysis from the orbiter’s perspective of a region near Venus’ equator reveals a volcanic vent that changed shape and increased in size dramatically over eight months.
The researchers say the images from the crater represent the first direct geological evidence of recent volcanic activity on the surface of Venus. A study detailing the findings was published in the journal Wednesday knowledgeIt was presented at the 54th Lunar and Planetary Science Conference in The Woodlands, Texas.
The Magellan mission became the first to image the entire surface of Venus before the spacecraft was deliberately plunged into the planet’s hot, toxic atmosphere in 1994 to collect a final set of data. But a fleet of new missions will be heading to Venus within a decade, including Truth, honestyVenus Mission Emissivity, Radio Science, Insar, Topography, and Spectroscopy Message.
Active volcanic landscape
The orbiter will use its instruments to unlock the secrets of why a planet similar in size to Earth is covered in volcanic plains and has an inhospitable atmosphere.
“NASA’s selection of the Veritas mission to look for recent volcanic activity in the Magellan data inspired me,” said the study’s lead author Robert Herrick, a research professor at the University of Washington. Alaska Fairbanks and a member of the Science Veritas team, in a statement.
“I really didn’t expect to be successful, but after about 200 hours of manually comparing images from different orbits of Magellan, I saw two images of the same area eight months apart showing telltale geological changes caused by a volcanic eruption.”
Herrick detected changes in images of Atla Reggio, a vast mountainous region that includes two of Venus’ largest volcanoes, Ozza Mons and Maat Mons. Both are similar to the largest volcanoes on Earth, Herrick said, but because of their lower slope, the volcanoes on Venus are more extensive.
Note that the vent on the north side of the domed volcano’s portion of Maat Mons changed hands between February and October 1991.
The Magellan image from February showed a circular vent spanning less than 1 square mile (2.2 square kilometers) with steep inner sides and areas of drained lava on the slopes.
Eight months later, the spacecraft took another image showing a completely different hole that appeared distorted, nearly doubled in size, and filled to the brim with a lake of lava.
Although the differences seem obvious, the two images were taken from opposite angles and perspectives and at a much lower resolution than the images taken by cameras on spacecraft today.
3D mapping of Venus
Herrick worked with Scott Hensley, Veritas project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, to create computer models of the vent to determine the likely cause of the changes.
“Only a few simulations match the images, and the most likely scenario is that volcanic activity occurred on the surface of Venus during the Magellan mission,” Hensley said. “Although this is only a data point for an entire planet, it confirms the presence of recent geological activity.”
Researchers believe that the pyroclastic flow Magellan witnessed in 1991 was similar to the one released by the 2018 Kilauea eruption in Hawaii.
“It was looking for a needle in a haystack with no guarantee that the needle was there,” Herrick said. “Finding a change that could be clearly confirmed as real was an absolute surprise. We were sure that Venus was volcanically active, but we didn’t know if eruptions occurred every few months, years, once every 10,000 years or more. All options would have matched the current data. Unless we’re incredibly lucky, we now know that the frequency is every few months or so, similar to the family of large intraplate basaltic volcanoes in Earth like Hawaii, Galapagos Islands, Canary Islands, etc.
Although it is possible that the earthquake caused the walls of the volcanic vent to collapse, the researchers believe that such activity would also have triggered a volcanic eruption.
Volcanoes act as windows into the planet’s interior, allowing scientists to better understand the factors that influence its ability to be a habitable world. Missions like VERITAS will help scientists better understand Venus, just as Magellan did decades ago.
The new mission will be equipped with radar to create 3D global maps of Venus and capture details about its surface composition, gravitational field and what happened in the planet’s past.
“Venus is a mysterious world, and Magellan has raised a lot of possibilities,” said Jennifer Witten, VERITAS co-principal investigator and assistant professor of Earth and Environmental Sciences at Tulane University in New Orleans, in a press release. “Now that we are certain that the planet experienced a volcanic eruption only 30 years ago, here is a small preview of the amazing discoveries Veritas will make.”