Juno's Microwave Radiometer Peeks Below Io's Crust
NASA's Juno spacecraft has gathered Microwave Radiometer (MWR) measurements that detect thermal emissions originating just beneath the surface of Io. The instrument senses microwave wavelengths that respond to heat from shallow subsurface layers, while infrared tools only register the topmost surface temperature.
The MWR's lowest frequency channels at 0.6 and 1.25 GHz are capable of penetrating several kilometers into Io's regolith, revealing warmth that rises from deeper layers. This enables scientists to trace how internal heat is transferred toward the moon's surface.
Such subsurface heat maps are crucial for understanding Io's extreme volcanism, driven by tidal flexing from Jupiter. By comparing MWR data with infrared imagery, researchers can distinguish surface hot spots from deeper heat sources.
The findings enrich our view of Io as a constantly evolving world, where interior processes continually reshape the landscape. Ongoing Juno flybys will provide additional opportunities to monitor temporal changes in subsurface thermal patterns.