17.03.2023
In a first, scientists have seen direct evidence of active volcanism on Earth’s twin, setting the stage for the agency’s VERITAS mission to investigate.
Direct geological evidence of recent volcanic activity has been observed on the surface of Venus for the first time. Scientists made the discovery after poring over archival radar images of Venus taken more than 30 years ago, in the 1990s, by NASA’s Magellan mission. The images revealed a volcanic vent changing shape and increasing significantly in size in less than a year.
Scientists study active volcanoes to understand how a planet’s interior can shape its crust, drive its evolution, and affect its habitability. One of NASA’s new missions to Venus will do just that. Led by the agency’s Jet Propulsion Laboratory in Southern California, VERITAS – short for Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy – will launch within a decade. The orbiter will study Venus from surface to core to understand how a rocky planet about the same size as Earth took a very different path, developing into a world covered in volcanic plains and deformed terrain hidden beneath a thick, hot, toxic atmosphere.
“NASA’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.”
This annotated, computer-simulated global map of Venus’ surface is assembled from data from NASA’s Magellan and Pioneer Venus Orbiter missions. Maat Mons, the volcano that has exhibited signs of a recent eruption, is within the black square near the planet’s equator. Credit: NASA/JPL-Caltech Full Image Details
The search and its conclusions are described in a new studypublished in the journal Science. Herrick also presented the findings at the 54th Lunar and Planetary Science Conference in the Woodlands, Texas, on March 15.
Modeling a Volcano
The geological changes Herrick found occurred in Atla Regio, a vast highland region near Venus’ equator that hosts two of the planet’s largest volcanoes, Ozza Mons and Maat Mons. The region has long been thought to be volcanically active, but there was no direct evidence of recent activity. While scrutinizing Magellan radar images, Herrick identified a volcanic vent associated with Maat Mons that changed significantly between February and October 1991.
In the February image, the vent appeared nearly circular, covering an area of less than 1 square mile (2.2 square kilometers). It had steep interior sides and showed signs of drained lava down its exterior slopes, factors that hinted at activity. In radar images captured eight months later, the same vent had doubled in size and become misshapen. It also appeared to be filled to the rim with a lava lake.
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.”
The scientists liken the size of the lava flow generated by the Maat Mons activity to the 2018 Kilauea eruption on the Big Island of Hawaii.
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.”
VERITAS will use state-of-the-art synthetic aperture radar to create 3D global maps and a near-infrared spectrometer to figure out what the surface is made of. The spacecraft will also measure the planet’s gravitational field to determine the structure of Venus’ interior. Together, the instruments will offer clues about the planet’s past and present geologic processes.
And whereas Magellan’s data was originally cumbersome to study – Herrick said that in the 1990s they relied on boxes of CDs of Venus data that were compiled by NASA and delivered in the mail – VERITAS’ data will be available online to the science community. That will enable researchers to apply cutting-edge techniques, such as machine learning, to analyze the planet and help reveal its innermost secrets.
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.
More About the Mission
VERITAS and NASA’s Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission were selected in 2021 under NASA’s Discovery Program as the agency’s next missions to Venus. VERITAS partners include Lockheed Martin Space, the Italian Space Agency, the German Aerospace Center, and Centre National d’Études Spatiales in France. The Discovery Program is managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the Planetary Science Division of NASA’s Science Mission Directorate in Washington.
Quelle: NASA
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Update: 29.05.2024
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Ongoing Venus Volcanic Activity Discovered With NASA’s Magellan Data
This computer-generated 3D model of Venus’ surface shows the volcano Sif Mons, which is exhibiting signs of ongoing activity. Using data from NASA’s Magellan mission, Italian researchers detected evidence of an eruption while the spacecraft orbited the planet in the early 1990s.
Credit: NASA/JPL
An analysis of data from Magellan’s radar finds two volcanoes erupted in the early 1990s. This adds to the 2023 discovery of a different active volcano in Magellan data.
Direct geological evidence of recent volcanic activity on Venus has been observed for a second time. Scientists in Italy analyzed archival data from NASA’s Magellan mission to reveal surface changes indicating the formation of new rock from lava flows linked to volcanoes that erupted while the spacecraft orbited the planet. Managed by NASA’s Jet Propulsion Laboratory in Southern California, Magellan mapped 98% of the planet’s surface from 1990 to 1992, and the images it generated remain the most detailed of Venus to date.
“Using these maps as a guide, our results show that Venus may be far more volcanically active than previously thought,” said Davide Sulcanese of d’Annunzio University in Pescara, Italy, who led the study. “By analyzing the lava flows we observed in two locations on the planet, we have discovered that the volcanic activity on Venus could be comparable to that on Earth.”
This latest discovery builds on the historic 2023 discovery of images from Magellan’s synthetic aperture radar that revealed changes to a vent associated with the volcano Maat Mons near Venus’ equator. The radar images proved to be the first direct evidence of a recent volcanic eruption on the planet. By comparing Magellan radar images over time, the authors of the 2023 study spotted changes caused by the outflow of molten rock from Venus’ subsurface filling the vent’s crater and spilling down the vent’s slopes.
Scientists study active volcanoes to understand how a planet’s interior can shape its crust, drive its evolution, and affect its habitability. The discovery of recent volcanism on Venus provides a valuable insight to the planet’s history and why it took a different evolutionary path than Earth.
Before starting its journey to Venus, NASA’s Magellan spacecraft was released while in Earth orbit by Space Shuttle Atlantis’ STS-30 mission. Captured in this May 4, 1989, photo, Magellan was the first planetary spacecraft to be launched from the shuttle.
Radar Backscatter
For the new study, published in the journal Nature Astronomy, the researchers likewise focused on archival data from Magellan’s synthetic aperture radar. Radio waves sent by the radar traveled through Venus’ thick cloud cover, then bounced off the planet’s surface and back to the spacecraft. Called backscatter, these reflected radar signals carried information about the rocky surface material they encountered.
The two locations studied were the volcano Sif Mons in Eistla Regio and the western part of Niobe Planitia, which is home to numerous volcanic features. By analyzing the backscatter data received from both locations in 1990 and again in 1992, the researchers found that radar signal strength increased along certain paths during the later orbits. These changes suggested the formation of new rock, most likely solidified lava from volcanic activity that occurred during that two-year period. But they also considered other possibilities, such as the presence of micro-dunes (formed from windblown sand) and atmospheric effects that could interfere with the radar signal.
To help confirm new rock, the researchers analyzed Magellan’s altimetry (surface height) data to determine slope of the topography and locate obstacles that lava would flow around.
“We interpret these signals as flows along slopes or volcanic plains that can deviate around obstacles such as shield volcanoes like a fluid,” said study co-author Marco Mastrogiuseppe of Sapienza University of Rome. “After ruling out other possibilities, we confirmed our best interpretation is that these are new lava flows.”
Using flows on Earth as a comparison, the researchers estimate new rock that was emplaced in both locations to be between 10 and 66 feet (3 and 20 meters) deep, on average. They also estimate that the Sif Mons eruption produced about 12 square miles (30 square kilometers) of rock — enough to fill at least 36,000 Olympic-size swimming pools. The Niobe Planitia eruption produced about 17 square miles (45 square kilometers) of rock, which would fill 54,000 Olympic swimming pools. As a comparison, the 2022 eruption of Mauna Loa in Hawaii, Earth’s largest active volcano, produced a lava flow with enough material to fill 100,000 Olympic pools.
“This exciting work provides another example of volcanic change on Venus from new lava flows that augments the vent change Dr. Robert Herrick and I reported last year,” said Scott Hensley, senior research scientist at JPL and co-author of the 2023 study. “This result, in tandem with the earlier discovery of present-day geologic activity, increases the excitement in the planetary science community for future missions to Venus.”
Figuring Out Volcanoes
Hensley is the project scientist for NASA’s upcoming VERITAS mission, and Mastrogiuseppe is a member of its science team. Short for Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy, VERITAS is slated to launch early next decade, using a state-of-the-art synthetic aperture radar to create 3D global maps and a near-infrared spectrometer to figure out what Venus’ surface is made of while also tracking volcanic activity. In addition, the spacecraft will measure the planet’s gravitational field to determine its internal structure.
“These new discoveries of recent volcanic activity on Venus by our international colleagues provide compelling evidence of the kinds of regions we should target with VERITAS when it arrives at Venus,” said Suzanne Smrekar, a senior scientist at JPL and principal investigator for VERITAS. “Our spacecraft will have a suite of approaches for identifying surface changes that are far more comprehensive and higher resolution than Magellan images. Evidence for activity, even in the lower-resolution Magellan data, supercharges the potential to revolutionize our understanding of this enigmatic world.”
More About the Mission
NASA’s VERITAS mission was selected in 2021 under NASA’s Discovery Program. Mission partners include Lockheed Martin Space, the Italian Space Agency, the German Aerospace Center, and Centre National d’Études Spatiales in France. The Discovery Program is managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the Planetary Science Division of NASA’s Science Mission Directorate in Washington.