Overview
- The Juno spacecraft gathered microwave data during close flybys in December 2023 and February 2024 that sampled depths of roughly 2 to 6 meters beneath Io’s surface.
- Researchers measured temperatures rising by more than 40°F just several feet down, a gradient far steeper than solar heating can produce.
- Two main interpretations fit the data: a pervasive conductive heat flow of about 1–3 watts per square meter across much of Io or cooling lava flows capped by roughly 9–11 meters of solid crust covering about 10% of the surface.
- The MWR maps show distinct warm anomalies that line up with volcanic centers, including a large 18–36°F warmer region near the Zal Montes Patera complex, and reveal broad low-density plains of pumice-like or ash-like material.
- Scientists say the result changes how we can study tidal heating and the movement of internal heat on icy and rocky worlds and that further Juno observations and analysis are needed to distinguish the heating mechanisms and measure their global importance.