An artist's concept shows the internal structure of Jupiter's moon Io. Data from NASA's Juno spacecraft suggests that Io does not have a shallow global magma ocean and is consistent with a mostly solid mantle (represented by green hues), with substantial melt (yellows and oranges), overlying a liquid core (red/black).

More information about Juno is at https://www.nasa.gov/juno and https://missionjuno.swri.edu.