Active lava flows on Venus raise the stakes for future exploration

Recently discovered lava flows on Venus suggest that the planet may be much more geologically active than originally thought, possibly as active as Earth.

First discovered by the Magellan spacecraft in the 1990s, the geological processes that produce these flows are likely still active today, making them a key area to monitor in future Venus missions.

Venus was once thought to be a “dead” planet, with geological activity long since ceasing, but a recent reanalysis of Magellan data has found compelling evidence of ongoing activity, including a volcanic vent that reshaped over the course of eight months. But direct evidence was scarce, and it was unclear how widespread this activity was.

Davide Sulcanese Researchers from D’Annunzio University in Chieti, Italy, reanalyzed Magellan radar data and looked at two different regions on Venus’ surface: the volcano Schif Mons in the north and Niobe Planitia in the east.

The researchers found that the brightness of the reflected radar signal changes over time, suggesting that there are areas where the material has expanded, possibly due to moving lava flows.

To confirm this explanation, Sulcanese and his team had to rule out other possibilities, such as atmospheric interference or the fact that Magellan only photographed the same area once every eight months, meaning the spacecraft inadvertently altered its intended viewing angle.

After confirming that the lava flows were volcanic, the researchers characterized them, including the rate at which lava was produced. The team’s low estimates are 3.78 and 5.67 cubic kilometers per year for Schif Mons and Niobe Planitia, respectively, roughly the same as the average volcano on Earth.

Sulcanese and his team used these numbers to extrapolate Venus’ total volcanic activity, which “infers that volcanism on Venus may be much more active than we expected,” Sulcanese said, and which would be on the same order of magnitude as Earth’s volcanic activity combined.

These areas will be important for Venus exploration missions such as NASA’s VERITAS and the European Space Agency’s EnVision, which aim to launch in the early 2030s. [these areas] “The volcano will remain active until the early 2030s,” Sulcanese said. “In geological terms, 30 years is like a few seconds for volcanic calvary activity.”

“This paper strengthens the case for current volcanic activity,” Philippa Mason Sulcanese, of Imperial College London, is also a member of the EnVision team, and says that known sites of geological activity like those they have identified can be imaged at least three times during an EnVision observation cycle, which would allow geological processes inside and on the surface of Venus to be viewed in much greater detail than the Magellan probe ever could.

“We still don’t know to this day how these processes work,” Sulcanese said. “Do we have some kind of single tectonic plate planet, or do we have things like microplates, or something different than the plates we have on Earth? By studying this volcanism, we can understand it better.”