Venus Reveals Its Secrets: Ancient Radar Data Hints at Subterranean Lava Tube
A new analysis of radar data from NASA’s Magellan spacecraft indicates the possible existence of a subterranean lava tube on Venus – the first structure of its kind identified on the planet. This discovery reinforces the importance of volcanism in Venus’s geological history.
Illustration of NASA’s Magellan spacecraft performing radar observations on Venus, with data indicating the presence of an underground lava tube.
RSLab, University of Trento
Volcanic Activity Beyond Earth
Volcanic activity isn’t unique to Earth. Evidence of features like lava tubes has been identified on the Moon and Mars and now a new study points to a similar structure deep beneath the surface of Venus, a planet whose surface and geology have been largely shaped by volcanic processes.
The discovery was made by researchers at the University of Trento, Italy, analyzing radar data as part of a project funded by the Italian Space Agency and published in Nature Communications.
Old Data, New Insights
The research is based on a new analysis of data collected by NASA’s Magellan spacecraft, which orbited Venus in the early 1990s. The results indicate the presence of a large subsurface cavity created by lava flow, the first structure of this type ever identified on the planet.
Radar data is consistent with a geological formation known as a lava tube, common in some volcanic regions on Earth and observed on the Moon, and considered likely on Mars.
Seeing Through Venus’s Clouds
Venus’s surface is permanently hidden by dense, toxic clouds, making direct observation difficult. However, radar can penetrate these clouds. The Magellan spacecraft used Synthetic Aperture Radar (SAR) to map the planet’s surface.
“Moving from theory to direct observation represents a major step forward, paving the way for new lines of investigation and providing crucial information for future missions to explore the planet,” emphasizes Lorenzo Bruzzone, a planetary scientist and radar expert at the University of Trento and senior author of the study.
Researchers analyzed data collected between 1990 and 1992, focusing on regions with signs of surface collapses, indicative of potential underground lava tubes. They used a recently developed analysis method capable of identifying cavities below the surface.
Radar image of Venus obtained by the Magellan spacecraft showing several crater chains and a pit, marked A, which potentially provides access to the subsurface.
L. Carrer, E. Diana, L. Bruzzone / Nature Communications
Location of the Lava Tube
The structure believed to be part of a lava tube is located on the western flank of Nyx Mons, a shield volcano approximately 362 kilometers wide, situated in the northern hemisphere of Venus. The region exhibits numerous craters caused by surface collapses.
“Our knowledge of Venus is still limited, and until now, we have never had the opportunity to directly observe the processes that occur beneath its surface,” explains Leonardo Carrer, a radar scientist at the University of Trento and lead author of the study.
Based on available data, scientists estimate the lava tube has an average diameter of about one kilometer, a roof at least 150 meters thick, and an empty cavity with a minimum height of 375 meters. Due to limitations in Magellan’s data, only the initial part of the structure could be observed, but researchers suggest it may extend for several kilometers.
These dimensions make the lava tube larger than those existing on Earth or predicted for Mars, reaching the upper limit of expected sizes and, in one case, already observed – on the Moon.
“Lava tubes are natural underground tunnels created by volcanic activity. They generally form within basaltic lava flows, where low-viscosity lava continues to move under a solidifying surface,” said Bruzzone.
The scientist emphasizes that, by its nature, a lava tube is not necessarily associated with active volcanism. However, he notes that “intense volcanic activity played an important role in shaping the surface and geology of Venus,” with recent studies suggesting some volcanoes on the planet may still be active.
Future Missions to Confirm the Discovery
Venus is the second planet from the Sun and has a diameter slightly smaller than Earth. The Magellan spacecraft mapped approximately 98% of its surface, revealing a planet with more volcanoes than any other in the solar system.
Despite this, Venus has received less scientific attention than Mars. This trend is expected to change with two missions already planned: the Envision mission from the European Space Agency and the Veritas mission from NASA. Both will carry advanced radar systems capable of obtaining high-resolution images.
The Envision mission will include a ground-penetrating radar, capable of probing the Venusian subsurface to depths of several hundred meters.
“The next decade promises to be crucial for Venus research,” concludes Carrer.
Venus captured by the Akatsuki spacecraft of the Japan Aerospace Exploration Agency in May 2016.
J. Greaves/University of Cardiff/JAXA via AP
Frequently Asked Questions
What is a lava tube?
A lava tube is a natural underground tunnel formed by flowing lava. As the outer layer of lava cools and hardens, the molten lava continues to flow beneath, creating a hollow tunnel.
Why is this discovery important?
What we have is the first potential lava tube identified on Venus, providing insights into the planet’s volcanic history and subsurface structure.
How was this lava tube discovered?
Researchers analyzed radar data collected by NASA’s Magellan spacecraft in the early 1990s, using a new analysis method to identify subsurface cavities.
What are the next steps in this research?
Future missions, such as the European Space Agency’s Envision and NASA’s Veritas, will use advanced radar systems to confirm the discovery and further investigate the subsurface of Venus.
