Juno uncovers Io's buried heat, hinting at lava flows or rapid subsurface conduction

NASA’s Juno spacecraft, using its Microwave Radiometer, measured Io’s subsurface temperatures for the first time and found a sharp, 40+ degree Fahrenheit rise within feet of the surface. The results from two close flybys (2023–2024) suggest heat moving through Io’s crust by conduction or stemming from buried lava flows, offering a new way to study tidal heating and heat transport on rocky worlds and potentially informing heat dynamics on other moons.