Venus is still alive. Scientists studying data sent by NASA‘s Magellan probe in the early 1990s claim to have identified an active volcano on Venus. The discovery, announced in an article published on Wednesday, March 15, is based on changes in the mouth of the planet’s largest volcano, Maat Mons.

“Where we made the discovery is the most likely place where there should have been volcanic activity” said Robert Herrick, a researcher at the University of Alaska’s Fairbanks Geophysical Institute, at the 54th Lunar and Planetary Science Conference (LPSC).

The discovery of the active volcano

Scientists have long known about lava flows on Venus. About 1,600 major volcanoes and nearly a million smaller ones dominate the planet’s surface. But until now there was no definitive evidence of ongoing volcanic activity.

The latest discovery marks the first time that scientists have found direct evidence of an active volcano on the surface of Venus. These eruptions, less explosive than those on Earth, occur at least a couple of times a year. So volcanoes still play a fundamental role in shaping the planet’s surface.

Scientists analyzed two images captured by the Magellan probe taken eight months apart in 1991. In those eight months, the volcanic mouth measuring 2 square kilometers became “notably larger” up to about 4 square kilometers.

In addition, the shape of the crater changed from circular in the first image to kidney-shaped with a dark interior in the second image captured after 8 months. This is evidence that “the volcano on Venus is active and has erupted on the planet’s surface” Herrick said during the LPSC presentation. The dark spot is probably the lava lake that filled the mouth up to the edge.

Magellan probe data

With limited data available, the team hypothesizes that Venus’s high pressure and boiling temperatures make the lava more fluid and therefore flow longer than it does on Earth. Venus is covered in volcanoes, so there are likely many other active ones waiting to be discovered.

The latest study covers only 1.5% of the planet, while about 40% has been surveyed twice by Magellan, giving scientists many radar images to examine. “There are still several volcanoes similar to Hawaii on Venus that I haven’t had a chance to look for, so there is much more to do there” Herrick said.

Although the Magellan images are 30 years old, Herrick attributed the timing of this discovery to recent improvements in software and hardware available to planetary scientists. Just like Google Earth, scientists can now easily download large data sets and zoom in and out of radar images, something they couldn’t do three decades ago.

The role of simulation

To confirm whether what they were seeing was indeed volcanic activity, Herrick collaborated with Scott Hensley, a project scientist for two upcoming NASA missions to the planet Venus.

“I was immediately cautiously optimistic and excited because it looked real,” Hensley said, adding that previous efforts had not yielded positive results. “We wanted to be very careful before confirming the discovery” Hensley said.

So, to rule out photographic artifacts, Hensley used Magellan’s data on the shape, depth, and other characteristics of the mouth to simulate hundreds of volcanic craters after an eruption. Sixty of these simulations are outlined in the paper published online Wednesday in the journal Science (rif.). “None of our simulations could mimic the kidney shape of the mouth. For this reason, we firmly believe that we have found a real change on the surface of Venus”.

Future missions to Venus

After 2030, a fleet of spacecraft will visit Venus. These include NASA’s VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy), the Davinci (Deep Atmosphere Venus Investigation of Noble gas, Chemistry, and Imaging) mission and the European Space Agency‘s (ESA) EnVision.

The DAVINCI mission will send an atmospheric probe into the clouds of Venus. While VERITAS and EnVision will scrutinize the planet’s surface from orbit for tiny centimeter-scale changes. “At this point, Magellan is state-of-the-art” Lori Glaze, director of NASA’s Planetary Science Division, told reporters. “This is the highest resolution we have. We really need VERITAS and EnVision on Venus in the next decade”.

DAVINCI is expected to launch in 2029, while VERIRAS, after a three-year delay, is expected to launch between 2032 and 2034, followed closely by EnVision, which will fly between 2035 and 2039. “Scientists studying Venus are very excited about these new missions. The data they will collect in the future will be more comprehensive and much easier to work with” Hensley said. “It will be a really exciting data set, and the entire Venus community is looking forward to getting their hands on this data”.

Stefano Gallotta
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