NASA's Juno spacecraft has provided the first measurements of temperatures beneath the surface of Jupiter's volcanic moon Io, revealing significant heating within its shallow subsurface. The findings, announced on August 4, 2026, offer new insights into the internal processes driving Io's intense volcanic activity.
Using data from Juno's Jovian Infrared Auroral Mapper (JIRAM) instrument, scientists detected heat emanating from shallow magma chambers just a few kilometers below Io's crust. This heating is likely caused by tidal flexingβthe gravitational pull from Jupiter and its moons stretching and squeezing Io as it orbits.
The discovery helps explain why Io, the most volcanically active body in the solar system, has more than 400 active volcanoes. The shallow heat sources may fuel the frequent eruptions and lava flows observed on its surface.
Juno, which has been studying Jupiter and its moons since 2016, continues to provide unprecedented data about the Jovian system. The mission's extended phase includes close flybys of Io, enabling detailed measurements of its thermal and geological features.
