Scientists analyzing old radar data from NASA's Magellan spacecraft have identified evidence of a large underground lava tube beneath Venus's surface near Nyx Mons. The structure, potentially a kilometer wide and extending dozens of kilometers, highlights the planet's volcanic past. This discovery, led by researchers at the University of Trento, was published in Nature Communications.
Volcanic features like lava tubes are known on Earth, Mars, and the Moon, and now evidence suggests they exist on Venus as well. Researchers from the University of Trento, supported by the Italian Space Agency, reexamined radar images from NASA's Magellan mission, which mapped Venus between 1990 and 1992 using synthetic aperture radar to penetrate the planet's thick cloud cover.
The team focused on areas with surface collapses, or skylights, that could indicate underlying voids. Their analysis revealed a subsurface conduit in the Nyx Mons region, interpreted as a possible lava tube with a diameter of about one kilometer, a roof at least 150 meters thick, and a depth of no less than 375 meters. "We analyzed Magellan's radar images where there are signs of localized surface collapses using an imaging technique that we have developed to detect and characterize underground conduits near skylights," said Lorenzo Bruzzone, the study's coordinator and a professor at the University of Trento. "Our analyses revealed the existence of a large subsurface conduit in the region of Nyx Mons... We interpret the structure as a possible lava tube (pyroduct), with an estimated diameter of approximately one kilometer, a roof thickness of at least 150 meters and an empty void deep of no less than 375 meters."
Venus's lower gravity and denser atmosphere may enable the formation of such large tubes by allowing molten lava to develop thick insulating crusts quickly. The identified structure is larger than typical Earth lava tubes and aligns with Venus's extensive volcanic channels. Surrounding terrain suggests the conduit could extend at least 45 kilometers, though confirmation requires higher-resolution data.
This finding aids in understanding Venus's geological evolution. "Our knowledge of Venus is still limited, and until now we have never had the opportunity to directly observe processes occurring beneath the surface of Earth's twin planet," Bruzzone explained. "The identification of a volcanic cavity is therefore of particular importance, as it allows us to validate theories that for many years have only hypothesized their existence."
Future missions, including the European Space Agency's Envision and NASA's Veritas, will carry advanced radar systems to probe deeper and map such features more precisely. The study appears in Nature Communications, authored by Leonardo Carrer, Elena Diana, and Lorenzo Bruzzone.