What lurks beneath the volcanoes of Jupiter's moon Io? NASA's Juno probe just took a peek

NASA’s Juno spacecraft recently captured data revealing the internal heat dynamics of Io, Jupiter’s most volcanically active moon. By using its Microwave Radiometer instrument, the probe peered between six and twenty feet beneath the moon’s surface. This marks the first time scientists have directly measured the temperature gradients in the subsurface crust of another world.

The findings show temperatures rising by more than 40 degrees Fahrenheit just a few feet underground. This heat indicates that energy moves from the molten interior through a conductive crust or pools of lava trapped near the surface. Researchers noted that these temperature spikes exceed what sunlight alone could produce. The moon’s surface appears surprisingly smooth, likely due to constant deposits of volcanic ash and sulfur frost.

This study provides a new method for monitoring volcanic activity. By analyzing how heat travels toward the surface before an eruption, experts hope to refine forecasting models for volcanoes here on Earth. Io serves as a natural laboratory because of the extreme tidal flexing caused by Jupiter’s gravity.

Beyond Earth, these techniques offer potential for studying other moons in the outer solar system. Juno has already used similar instruments to examine Europa and Ganymede. Understanding how heat moves through icy crusts remains a primary goal for scientists searching for environments capable of supporting life in the distant reaches of the solar system.