The recent flybys of NASA's Juno spacecraft above Io has revealed that the surface of this Jupiter moon is filled with lava lakes. In a new paper published in the journal Nature Communications Earth and Environment, researchers said that they have noted new features of Io's surface thanks to Juno's infrared instrument.

The floor is lava!

No, but really. New findings from @NASA's Juno probe show how widespread lava lakes are on Jupiter’s hottest moon, Io! Scientists have a few theories about these fire-breathing lakes: https://t.co/SQLuT6gC5p pic.twitter.com/jl0r0VkcGo — NASA JPL (@NASAJPL) June 26, 2024

The instrument captures infrared light and reveals features that are not visible beneath the cloud tops. Studying the data gathered by Juno in May and October 2023, scientists found the moon's surface filled with lava in caldera-like features.

"In the region of Io’s surface in which we have the most complete data, we estimate about 3% of it is covered by one of these molten lava lakes," said Alessandro Mura, a Juno co-investigator.

The first volcanic activity was documented by Voyager 1 and astronomers believe the activity is a result of Io being stretched and squeezed by gravitational pull of Jupiter and neighbouring moons. There are many other theories on the types of volcanic eruptions across Io's surface.

Thanks to the infrared data, collected by Juno's Jovian Infrared Auroral Mapper (JIRAM) instrument, scientists also found hints about recycling of melt. It means there is a balance between melt that has erupted into the lava lakes and melt that is circulated back into the subsurface system.

"We now have an idea of what is the most frequent type of volcanism on Io: enormous lakes of lava where magma goes up and down," Mura said.

Discovered in 1610 by Galileo, Io has intrigued astronomers for decades due to its mysterious features. More Juno fly bys which will continue for several years are expected to find more clues into what makes Io the most volcanically active region in the solar system.

Meanwhile, Juno just completed its 62nd flyby of Jupiter on June 13 and it's next close encounter is scheduled for July 16, says NASA.

(Image: NASA)