Venus has lava tubes, and they’re weird

Recent research has confirmed the existence of enormous lava tubes on Venus, providing startling insights into the planet’s geological characteristics.

On Earth, lava tubes are well-documented, with similar formations found on the Moon and Mars. These tubes typically are more cavernous on smaller planets, largely due to weaker gravity preventing the rock from collapsing. For instance, some lunar tubes are so expansive that they have been proposed as potential habitats for astronauts, offering protection from harmful solar radiation.

While prior observations indicated potential lava tubes on Venus through the detection of surface features like holes and depressions, the true cause remained unknown. Some speculated they could have been due to geological activity, such as fault movements, rather than underground lava formations.

However, Barbara De Toffoli from the University of Padova, Italy, and her research team have now identified clear evidence of lava tubes on Venus. Their findings reveal that these tubes are unexpectedly wide, displaying volumes comparable to those on the Moon, and challenge the traditional understanding of lava tube formation on planets that are more similar to Earth in terms of mass and gravitational strength.

“The trend we’ve observed shows that the lava tubes on Earth are smaller, those on Mars are moderately bigger, and the Moon has the largest tubes. Venus, however, seems to break that trend with its particularly large tube volumes,” De Toffoli explained during the Europlanet Science Congress held in Helsinki, Finland, earlier this month. “This discrepancy suggests that unique factors on Venus must be influencing the development of these structures.”

Using advanced radar and mapping data from earlier missions, De Toffoli and her team investigated the spatial arrangement of these tubes relative to large volcanoes on the planet. They pinpointed four distinct examples that could not be attributed to alternative geological processes like tectonic shifts. The observed alignment of the pits conformed with the steep slopes of the volcanoes, indicating the direction lava would have traversed, and the ratios of depth to width matched known lava tube characteristics.

The notable width of the tubes suggests that the extreme conditions on Venus—characterized by intense heat and high atmospheric pressure—might significantly influence the flow behavior of molten rock beneath the surface. De Toffoli mentions, “The high pressure on Venus leads to a flattening of the tubes, which differs from the intense erosion typically observed on other planets.”