NASA’s Juno Probe Has Seen Inside The Solar System’s Most Volcanic World, And It's Pretty Hellish In There

NASA’s Juno mission recently provided a clear look at the internal conditions of Io, Jupiter’s most volcanic moon. By using a specialized Microwave Radiometer instrument during two close flybys, scientists mapped temperatures beneath the surface. The data reveals that while the surface remains cold, the interior experiences significant heating, likely caused by intense tidal forces as the moon orbits Jupiter.

These gravitational shifts create a constant stretching and squeezing effect on the moon. This movement generates extreme heat that drives the volcanic activity observed across its landscape. The mission team noted that the temperature gradient under the surface is much steeper than solar heat alone could account for. This suggests that heat is rising steadily through the crust from deep inside.

In addition to the heat maps, the team discovered that large portions of Io’s surface are remarkably smooth, resembling vast plains. The composition appears to consist of low-density materials like volcanic ash or pumice. These findings offer a new way to study planetary geology, as the techniques used at Io might eventually help experts understand the mechanics of volcanoes on Earth.

This research represents the first time scientists have successfully measured temperatures below the surface of a rocky, volcanic moon. It provides a unique opportunity to see how tidal heating functions as a fundamental energy source throughout the solar system. The data is already changing how we interpret the activity on moons like Europa and Ganymede, which also rely on these internal heat sources for their subsurface oceans.