by Venus is still alive.
Scientists study data sent home by NASAs Magellan spacecraft early 1990s say they noticed volcanic activity Venus. The discovery, announced in a paper published Wednesday (March 15), is based on changes to a vent near one of the world’s largest volcanoes, Mate Bergen.
“Where we made the discovery is the most likely place there should have been new volcanism,” Robert Herrick, a researcher at the University of Alaska’s Fairbanks Geophysical Institute, said Wednesday (March 15) at the 54th Lunar and Planetary Science Conference (LPSC). ) is held in Texas and virtually.
Related: Planet Venus: 20 interesting facts about the torrid world
Scientists have long known about lava flows on Venus from volcanoes that erupted a few million years ago. Although about 1,600 major volcanoes and nearly a million smaller ones dominate the planet’s surface, it’s debatable whether any of them are still blazing.
The latest finding is the first time scientists have found direct evidence of recent volcanic activity on the surface of Venus, Earth’s closest neighbor. They think such eruptions — less explosive than those on Earth — occur at least a few times a year, adding to growing evidence that volcanoes play an important role in shaping the planet’s youthful surface.
In the latest study, scientists analyzed two Magellan images taken eight months apart in 1991. In those eight months, they noticed that a volcanic vent measuring 0.7 square miles (2 square kilometers) grew “significantly larger,” to about 1.5 square miles (4 square kilometers).
Related: 10 Incredible Volcanoes In Our Solar System (Photos)
They saw that the shape of the vent had also changed: it was round in the first image, while the second showed it to be kidney-shaped with a dark interior, evidence of “a volcano erupting on the surface of Venus ‘. Herrick said during his presentation at LPSC. The dark spot is likely a lava lake filling the gap to the brim, he added.
With the limited data available, the team speculates that Venus’s high pressure and sweltering temperatures make the lava more fluid and keep it flowing longer than on Earth.
Venus is overwhelmingly covered in volcanoes, so there are likely many more active volcanoes waiting to be discovered. Herrick said he stopped searching after making the discovery, but “still a long way from all the potential searching for new things with the Magellan data.”
The latest study covers only 1.5% of the planet, while about 40% has been imaged twice by Magellan, giving scientists plenty of radar images to sift through.
“There are still several Hawaiian volcanoes on Venus that I haven’t been able to search, so there’s a lot more to do there,” Herrick said.
Related: Scientists hail ‘the decade of Venus’ with 3 new missions on the way
A discovery from 30 years old data
The Magellan spacecraft arrived at Venus in 1990 and spent two years taking pictures from orbit. During this time, the spacecraft revisited the same spots once every eight months. Back then, the purpose of each visit wasn’t to look for changes on the surface, as scientists do now, but to perform a variety of other tasks, so the images ended up being at different angles and heights, Herrick said. Both images related to the discovery can be seen as being shot from windows on different sides of an aircraft, he added.
The first image – taken as if the vent was viewed from a window on the left side of the plane – shows that the vent is circular. The second image – clicked from a window on the right – shows a kidney-shaped opening with shorter, collapsed walls likely several hundred feet deep. Herrick also noticed a brighter spot on the ground further downhill, which he believes is a new lava flow that spewed out of the volcano.
Although the Magellan images are 30 years old, Herrick attributed the timing of this discovery to recent improvements in software and hardware for planetary scientists. Like Google Earthscientists can now easily download large data sets and zoom in and out of radar images, which was not possible three decades ago.
Because Magellan’s images were clicked at different angles, Herrick and his team chose points on the surface of Venus that remained the same in both images, and processed them to look like they had been seen from above. The process, called orthorectification, helps scientists convert raw images into a format suitable for modeling.
“We really wanted to make it clear that the difference we saw in the vent couldn’t in any way be a factor of simply looking at the same feature from different angles,” Herrick said during his presentation at LPSC.
Is it really a volcano?
To confirm whether what they saw was really volcanic activity, Herrick teamed up with Scott Hensley, a project scientist for two of NASA’s upcoming Venus missions.
“I was immediately cautiously optimistic and excited, because it looked real,” Hensley said, adding that previous attempts to look for similar changes in the images have yielded no positive results. In addition, many features that didn’t change on Venus looked different in different Magellan images, thanks to variations in lighting and spacecraft angles.
“We wanted to be very careful here that we actually had something,” Hensley said.
So to rule out that the spacecraft angles themselves were responsible for the changes they saw, Hensley used Magellan data on the shape, depth, and other features of the vent to simulate hundreds of volcanic vents, 60 of which are described in the new paper (opens in new tab)which was published online Wednesday in the journal Science.
“None of our simulations could replicate the kidney shape of the vent,” he said, adding that their simulations also failed to show a dark floor in the vent that Magellan noticed. “That’s what led us to believe very strongly that we had a real change on the surface of Venus.”
‘The Decade of Venus’ is likely to reveal more volcanic activity
In the 2030s, a fleet of spacecraft will visit the neighboring planet, including NASA’s VERITAS (or Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy) and DAVINCI (Deep Atmosphere Venus Investigation of Noble gass, Chemistry and Imaging) and Europe’s Imagine.
DAVINCI will send an atmospheric probe into the clouds of Venus, and VERITAS and EnVision will peer through the planet’s thick atmosphere from orbit, looking for tiny, “centimeter-wide changes” on the planet’s surface — far more than what scientists can do only with Magellan’s data.
“Right now, Magellan is the state of the art,” Lori Glaze, director of NASA’s Planetary Science Division, told reporters at the conference. “That’s the highest resolution we have. We really need to get VERITAS and EnVision to Venus within ten years.”
DAVINCI will start in 2029. After a delay that delayed its launch by three years, VERITAS now scheduled to launch between 2032 and 2034, closely followed by EnVision, which will fly between 2035 and 2039. Venus scientists looking for signs of continued volcanic activity are thrilled that these new missions won’t have the one-sided viewing problem that Magellan had, so future data will be a lot easier to work with, Hensley said.
“It’s going to be a really exciting data set and the entire Venus community can’t wait to get their hands on this data,” he said.
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