Radar data suggest ancient volcanic tunnel beneath Venus

Scientists studying decades-old radar data from NASA’s Magellan mission say Venus may hide a vast underground tunnel formed by ancient volcanic eruptions, offering new insight into the planet’s interior and geological history.

According to researchers, the structure appears to be a lava tube created when molten material flowed beneath the surface and later drained away, leaving an empty passage.

If confirmed, it would be only the second lava tube ever reported on Venus and would add to evidence that the planet remains geologically active.

The findings are based on an analysis of radar images collected by the Magellan spacecraft between 1990 and 1992. The spacecraft used radio waves to map Venus through its thick cloud cover. A report published in Nature Communications said the radar data revealed long stretches of pitted terrain that scientists interpret as collapsed roofs of underground volcanic tunnels.

One of the clearest features was detected on the western flank of Nyx Mons, a massive volcano that is among thousands found on Venus. Researchers said such roof collapses can create skylight-like openings that expose empty spaces below the surface. The radar signal from the area closely resembles patterns previously identified in lava tubes on the Moon and Mars.

The analysis suggests the underground passage could extend for several dozen kilometres, although only parts of it can be confirmed with existing data. Direct observation of Venus remains difficult due to its dense atmosphere, making radar the primary tool for studying its surface and subsurface features.

Scientists said future radar missions, including the European Space Agency’s EnVision mission, could help confirm the size and structure of the tunnel and provide a clearer picture of Venus’s hidden volcanic network.