NASA's Juno mission has provided the first measurements of temperature below the surface of Jupiter's moon Io, according to reports. Io is the most volcanically active world in the solar system, with hundreds of active volcanoes that can shoot sulfur plumes more than 500 kilometers above its surface.
The data were collected during two close flybys of Io by Juno, as stated in the mission reports. The Microwave Radiometer (MWR) instrument aboard the spacecraft is said to have been used to collect the data.
Io has hundreds of active volcanoes capable of ejecting sulfur plumes over 500 km high.
Most of Io's surface is remarkably smooth and composed of material with very low density, based on analysis of the MWR data. According to unverified reports, during Perijove 57 on Dec. 30, 2023, Juno primarily mapped the northern hemisphere of Io.