In a first, researchers have directly observed signs of ongoing volcanism on Earth’s twin, setting the scene for the investigational agency’s VERITAS mission.
For the first time, direct geological proof of recent volcano activity has been found on Venus’s surface. After carefully studying old radar images of Venus taken by N.A.S.A’s Magellan mission more than 30 years ago, in the 1990s, scientists made the finding. Images showed a volcanic vent that had grown considerably in size and changed shape in less than a year.
Venus is sometimes called Earth’s “evil twin” because despite being similar in size and composition to Earth, its surface is incredibly hostile, with a thick atmosphere of carbon dioxide and clouds of sulfuric acid. The extreme greenhouse effect on Venus has caused its surface temperature to soar to over 900 degrees Fahrenheit (475 degrees Celsius), hot enough to melt lead. In contrast, Earth has a much milder climate and is much more hospitable to life as we know it. Therefore, Venus is often seen as Earth’s “evil twin” because it presents a stark contrast to our planet’s relatively benign conditions.
To comprehend how a planet’s interior can shape its crust, drive its evolution, and impact its habitability, scientists research active volcanoes. That is what one of N.A.S.A’s newest trips to Venus will do. Within a decade, VERITAS, an acronym for Venus Emissivity, Radio science, InSAR, Topography, and Spectroscopy, will begin under the direction of the N.A.S.A Jet Propulsion Laboratory in Southern California. To comprehend how a rocky planet roughly the size of Earth took a very different path, developing into a world covered in volcanic plains and deformed terrain concealed beneath a thick, hot, toxic atmosphere, the orbiter will study Venus from surface to core.
“N.A.S.A’s selection of the VERITAS mission inspired me to look for recent volcanic activity in Magellan data,” said Robert Herrick, a research professor at the University of Alaska Fairbanks and member of the VERITAS science team, who led the search of the archival data. “I didn’t really expect to be successful, but 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.”
The search and its conclusions are described in a new study published in the journal Science. Herrick also presented the findings at the 54th Lunar and Planetary Science Conference in the Woodlands, Texas, on March 15.
Maat Mons is displayed in this computer-generated, three-dimensional perspective of the surface of Venus. The viewpoint is located 634 kilometers (393 miles) north of Maat Mons at an elevation of 3 kilometers (2 miles) above the terrain. Lava flows extend for hundreds of kilometers across the fractured plains shown in the foreground, to the base of Maat Mons. N.A.S.A Magellan mission synthetic aperture radar data is combined with radar altimetry to develop a three-dimensional map of the surface. The vertical scale in this perspective has been exaggerated 10 times. Credit: N.A.S.A/JPL
Modeling a Volcano
The Atla Regio, a vast highland area near Venus’ equator that is home to two of the planet’s biggest volcanoes, Ozza Mons and Maat Mons, is where Herrick discovered the geological changes. Although there was no concrete evidence of recent activity, the area has long been considered to be volcanically active. Herrick discovered a volcanic vent connected to Maat Mons that underwent a major change between February and October 1991 while examining Magellan radar images.
The vent looked nearly circular and less than one square mile in size in the February image. (2.2 square kilometers). It had lava draining down its exterior slopes and steep inner sides, which suggested activity. The same vent appeared to have doubled in size and changed form in radar images taken eight months later. Additionally, it seemed to be completely surrounded by a lava pool.
But because the two observations were from opposite viewing angles, they had different perspectives, which made them difficult to compare. 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 various configurations to test different geological-event scenarios, such as landslides. From those models, they concluded that only an eruption could have caused the change.
“Only a couple of the simulations matched the imagery, and the most likely scenario is that volcanic activity occurred on Venus’ surface during Magellan’s mission,” said Hensley. “While this is just one data point for an entire planet, it confirms there is modern geological activity.”
Magellan’s Legacy
Herrick, Hensley, and the rest of the VERITAS team are eager to see how the mission’s suite of advanced science instruments and high-resolution data will complement Magellan’s remarkable trove of radar imagery, which transformed humanity’s knowledge of Venus.
“Venus is an enigmatic world, and Magellan teased so many possibilities,” said Jennifer Whitten, associate deputy principal investigator of VERITAS at Tulane University in New Orleans. “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.”
Modern synthetic aperture radar and a near-infrared spectrometer will be used by VERITAS to generate 3D global maps and determine the composition of the surface. To ascertain Venus’ internal structure, the spacecraft will also analyze the planet’s gravitational field. The sensors’ combined findings will provide information about the planet’s recent and historical geologic processes.
The science community will be able to access the data from VERITAS online, unlike Magellan’s data, which was initially difficult to study. According to Herrick, in the 1990s they depended on boxes of CDs of Venus data that were compiled by N.A.S.A and delivered by mail. That will make it possible for researchers to analyze the planet and assist in revealing its deepest mysteries using cutting-edge techniques like machine learning.
Those studies will be complemented by EnVision, an ESA (European Space Agency) mission to Venus slated for launch in the early 2030s. The spacecraft will carry its own synthetic aperture radar (called VenSAR), which is being developed at JPL, as well as a spectrometer similar to the one VERITAS will carry. Both Hensley and Herrick are key members of the VenSAR science team.
Reference: “Surface changes observed on a Venusian volcano during the Magellan mission” by Robert R. Herrick and Scott Hensley, 15 March 2023, Science.DOI: 10.1126/science.abm7735
More About the Mission
In 2021, NASA chose the VERITAS and DAVINCI missions as their next ventures to Venus under the Discovery Program. VERITAS has collaborated with several organizations, including Lockheed Martin Space, the Italian Space Agency, the German Aerospace Center, and France’s Centre National d’Études Spatiales. The Planetary Missions Program Office at N.A.S.A’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for NASA’s Science Mission Directorate’s Planetary Science Division in Washington
Soucre: scitechdaily.com
