It’s not a large moon compared to some of its neighbors, but Jupiter’s moon Io is very active, with volcanoes spewing hundreds of lava columns. Dozens of miles Above its surface, according to NASA. Infrared technology aboard the space agency’s Juno probe mapped two such eruptions in February, bringing back valuable data about mysterious events beneath Io’s surface. The researchers shared their views on this issue in paper Published last week.
From about 2,400 miles away, the probe’s Jovian Infrared Auroral Mapper (JIRAM) revealed that Io’s entire surface is covered with lava lakes in caldera-like features, explained Alessandro Mora, a Juno co-investigator from the National Institute of Astrophysics in Rome. On Earth, a caldera is a crater formed by the collapse of a volcano. Io is about a quarter the size of Earth in diameter, and slightly larger than Earth’s moon.
“In the area of Io’s surface where we have the most complete data, we estimate that about 3% of it is covered by some kind of molten lava lake,” Mora said. Juno’s JIRAM instrument came via the Italian space agency Agenzia Spaziale Italiana.
According to Mora, lead author of the Io paper, the probe’s flyby reveals the most common type of volcanism on Jupiter’s hottest moon — “enormous lakes of lava where magma rises up and down.”
He added: “The lava crust is forced to break off the lake walls, forming the typical lava ring that appears in lava lakes in Hawaii.” The walls are likely to be hundreds of meters high, which explains why magma spills are generally not observed.
Researchers are still studying data collected by the two Juno missions around Io, which occurred in February 2024 and December 2023.
