"Earth lava tubes have smaller volumes, Mars tubes have slightly bigger volumes, and then the Moon'stubes have even bigger volumes," said University of Padova researcher Barbara De Toffoli during the Europlanet Science Congress in Finland earlier this month, as quoted by New Scientist. "And then there's Venus, completely disrupting this trend, displaying very, very big tube volumes."
Scott Bolton's first encounter with Io took place in the summer of 1980, right after he graduated from college and started a job at NASA. The Voyager 1 spacecraft had flown past this moon of Jupiter, catching the first glimpse of active volcanism on a world other than Earth. Umbrella-shaped outbursts of magmatic matter rocketed into space from all over Io's surface.